Chapter 12: indoor plants.
forcing interiorscaping understory
The earliest experiences many people have with plants involve indoor plants. Indoor plants have been extremely popular at various stages in history, which has led to the popularity of inventions such as the terrarium and self-watering pots. During Victorian times, large ferns and other potted plants were favorites. With increased urbanization and the advent of modern high-rise buildings serving as homes and offices, people have included plants in their lives by bringing nature indoors where they spend much of their time. The profession of interiorscaping has grown as a result of this trend (Fig. 12-1). Taking care of indoor plants begins with understanding the needs of individual plants and learning how best to provide them (Figs. 12-2 and 12-3). Table 12-1 lists various types of houseplants and some of their basic requirements.
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Foliage plants suitable for indoors perform so well because of the environments they evolved in. Many were initially collected from the understory of rainforests where light levels can be quite low (Fig. 12-4, see page 209). The understory consists of young plants of canopy trees, some shrubs, and herbaceous plants.
People enjoy plants indoors for their aesthetic value, but plants also are good for the environment. They take up carbon dioxide and give off oxygen, of course, but many houseplants do much more: they clean up pollutants in the environment. Chemicals, such as formaldehyde, that are given off by furniture and carpeting are removed from the air by many houseplants. (See Table 12-2 for plants and the pollutants they remove.) One potted plant per 100 square feet of floor space is enough to help clean the air in the average home or office. More plants would increase the rate of pollutant removal. Indoor plants also bring beauty and nature indoors. In this respect, they have a positive impact on people's attitudes and moods.
Growing plants indoors requires special consideration in all areas of plant culture: lighting, soilless media, temperature, and humidity. Pest and disease control methods will also probably vary from those used for outdoor plants, whether in the home environment or on a larger scale in an office, hotel, or shopping center. Fertilization techniques will be similar to those for other container-grown crops, but timing will differ because of the different growth habits inside a home or other building compared with growth in a greenhouse. Finally, it is helpful to consider the origins of the houseplants you wish to grow. The more closely you can replicate the natural conditions in which they evolved, the more successful you will be growing them in your home. Temperate and tropical areas both experience changing seasons. In temperate areas, these seasons are vastly different, with regard to changing temperatures, daylength, and precipitation. However, in the tropics, daylength varies little to not at all, and the seasons change between rainy and dry, and there may be only 10-20[degrees]F differences in temperatures. You may need to replicate these conditions to provide dormancy periods or simply to allow the plant to experience its natural cycles throughout the year.
A major consideration when deciding to grow plants indoors is light. Most homes have very low levels of light, with perhaps only a few percent of the amount of light outside on a sunny day. Even when a plant is placed in a sunny window, the light is often inadequate to support its growth. Sunny windows still generally only receive direct light for a few hours a day, if at all. Therefore, the success of plants that have become familiar houseplants is due precisely to the fact that they can survive and even grow in low light conditions. Thus, plants for the indoor environment should be selected for the light level that is available. Plants and their optimal light levels are listed in Table 12-3.
Rooms in a home provide differing levels of light, depending on their orientation to the sun, which moves throughout the day and throughout the year. East-facing windows provide sun in the morning, which is considered a good time of day for plants to receive light because it has a positive effect on photosynthesis. After the long period of dark, during which existing resources for energy have been used for respiration, the plant requires additional photosynthates for optimal growth. Accumulation of the photosynthates begins as soon as the plant receives the light energy required for photosynthesis.
South-facing windows may provide sunlight throughout the day, if there are no obstructions from outside. Often this light will be direct. In the Northern Hemisphere, north-facing windows will not provide much direct light at all. In summer, some direct light may come in from the north in the early morning or late afternoon because of the angle of the sun. Any overhang on the house will further reduce the amount of light that enters. Plants that are placed near north-facing windows or in locations where they do not receive any direct light must be well-adapted to low light levels. Figure 12-5 illustrates light levels at different windows in the house. West-facing windows receive sunlight late in the day and during the warmest part of the day. If your house or building is air-conditioned, the warmth from windows will not have much effect.
Before placing a plant at any particular window, observe the length of time a window receives light throughout the day and how much direct sunlight enters the window. Be aware of the changing angle of the sun throughout the year, noting that it will be lower in the southern sky in the winter. Take note of outdoor features such as walls, fences, shrubbery, trees, and overhangs that may interfere with the sunlight. These observations will provide some guidance as to the type of plants you can place at various locations inside the house.
Although many houseplants are used primarily for their foliage, some houseplants will also produce flowers. Geraniums, orchids, cyclamen, and camellias are just a few flowering plants that are grown indoors. Many flowering plants require higher light levels to produce flowers. If the plants you wish to grow require higher light levels than are available in your home or building, then you should consider setting up special lighting.
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You can address the lighting problem in a variety of ways. One is to purchase a small grow-lamp and place it in a corner of the room with a single plant. Another is to construct a special room with racks of shelving for plants and banks of lights over each shelf. Other options fall in between these two extremes. All of these options have been used and serve the purpose for which they were intended. Orchid lovers, for example, may construct a special room in their home, convert a basement into a plant-growing room, or install lighting in a bathroom or spare room of the house to provide the conditions required for their plants to thrive. The key to success with artificial lighting is to understand the quality and quantity of light provided by the lamp you intend to use. See chapter 7 for a discussion on artificial light sources.
The temperature inside a home does not fluctuate as much as the outside temperature. As temperatures rise, plants utilize stored foods through respiration at an increasing rate. Therefore, if a plant is in a warm location, it will require a higher light level, as well as more water and fertilizer. Every house has its own temperature conditions, and these often vary from room to room. Temperatures often vary inside the home throughout the year. Therefore, it is important to understand the needs of the plants you are trying to grow and place them in the proper environment in your home. To be most successful, you may not be able to grow certain plants if your home cannot provide the proper temperature ranges.
Sometimes household temperatures are too cool for plants, especially in a cool basement or near windows. If a plant is too cold, you may notice older leaves becoming limp, turning yellow and dropping off. Flower bud blasting and new leaves that are smaller than normal and slightly curled are other symptoms. Revive such plants by moving them to a warmer location.
Some plants may require cool temperatures or even chilling (see chapter 7 for a discussion on chilling) for initiation of flowers. Such plants are normally considered outdoor plants, and these include tulips, daffodils, and hyacinths. However, by providing the chilling requirement for floral buds to complete their development, you may grow these bulbs indoors, providing flowers in the middle of winter. This is a process known as forcing, which refers to providing the proper environmental conditions for flower formation to occur without waiting for natural events to take place. This generally requires providing cool temperatures for a specified period of time. Bulb forcing is a science that was studied by Dr. Gus De Hertogh in the 1960s (see box).
In temperate climates, winter is never over soon enough. This fact helps explain why florist shops are full of spring-blooming bulbs for Valentine's Day. But anyone who knows the secrets of flower development in bulbs can recreate this welcome sight in his or her own home by using the following procedure, which requires very little special technology or equipment. Bulbs that readily respond to this treatment include daffodils, paper whites, narcissus, hyacinth, crocus, and grape hyacinth (Muscari). Tulips are more challenging, usually requiring two or more stages with different temperatures at each stage. Specific tulips have requirements that are maintained as trade secrets by bulb producers.
If you want to force bulbs, begin by attaining high-quality bulbs of the desired species. Check to make sure they are not dry or shriveled and do not have pest or disease damage. Plant the bulbs in pots containing potting soil, with their noses pointed upward and emerging a bit from the soil. They should be planted fairly close to each other or even touching. Water them in and do not allow the soil to dry out throughout this entire process.
Place the potted bulbs in a cold place, such as refrigerator, unheated attic, garage, or cellar, about 35 to 45[degrees]F. Do not allow them to freeze or they will be destroyed. Allow them to remain in these cool conditions for 12 to 13 weeks (see Table 12-4 for specific requirements). Once the shoots begin to emerge you will know it is time to remove the potted bulbs from the cool conditions and begin providing warm conditions. You can achieve this by simply placing the pots at room temperatures indoors. Water as you normally would. Room temperatures above 55[degrees]F are adequate to encourage leaf and flower emergence. The cooler the temperature is, the longer lasting the flowers will be. If plants stretch too much, they are not receiving enough light and should be moved to a lighter or sunnier location.
To have blooming plants when you like, time your starting date to the desired bloom time. Bulbs will bloom in about 4 weeks from the time they are removed from the cool conditions. Bulbs cannot be forced a second year and should be planted outdoors after flowering. Hyacinths and tazetta narcissi will grow in water alone. Purchase special vases designed to hold the bulb above the water level. Amaryllis is a tropical plant and does not require chilling. Under natural conditions it responds to a moist and dry period. Amaryllis bulbs are often sold as a Christmas gift because of the ease with which they bloom indoors.
Many house plants originated in humid tropical climates, whereas others, such as cactus, evolved in arid climates. Houses tend to be dry, especially in winter when they are heated, but also in summer, when air conditioning is used. Air conditioners remove moisture as they cool the air. Special efforts may be required to create conditions for plants that thrive in humid environments. Some plants may be placed in a bathroom, where humidity is high at some times. But not all bathrooms have ample space or lighting for this to be a practical solution. Humidifiers can be a good solution, because there is some evidence that dry air leads to more colds in the winter, and, thus, humidifiers can be beneficial to both plants and humans. Although it is a bad idea to allow a plant to remain in standing water, it is permissible to place a saucer filled with water and a layer of pebbles under the pot. The pot should stand atop the pebbles without touching the water, and this will increase the humidity around the plant (Fig. 12-6). Check the water regularly and refill as needed. Misting plants regularly with a spray bottle is also beneficial.
Houseplants vary in their requirements for moisture. The best way to control the moisture level for plants is to use appropriate soil or soilless media. For plants that prefer dry soil, use a better-draining, less moisture-retentive medium such as a sandy mix or a mix with higher levels of perlite. For moisture-loving plants, include some natural soil with clay in it. Vermiculite can help with moisture retention, too.
Although some houseplants require more water than others, overwatering is the leading cause of houseplant death. The amount of watering required varies by the type of plant, the type and size of the pot, the type of soil or soilless media, temperature and humidity, sun or light exposure, and time of year.
Larger pots will retain more water than small pots, but if the plants in them have a well-developed root system or large leaves, they may still lose water quickly. Shallow pots stay wet longer than deep ones because of the reduced gravitational pull on excess moisture. Thus, it is not a good idea to add rocks to the bottom of a pot to "improve drainage," as some sources suggest. Adding rocks actually reduces soil depth, resulting in slower draining. The best way to improve drainage is to add sand, perlite, or another coarse material to the soil or soilless medium. Shallow containers and poor drainage can be a special challenge in the case of bonsai plants (see box). Use a well-draining medium with small-sized gravel to help alleviate this situation. Unglazed clay pots are porous and lose moisture through their sides. Plastic and glazed clay pots retain water better (Fig. 12-7).
Plants on a sunny windowsill will grow faster than those with less light exposure. They may also heat up, resulting in water loss from the medium by evaporation. The higher humidity in bathrooms will contribute to reduced moisture loss. Plants should be checked daily for moisture status. As they grow and become larger or have more leaves, houseplants will require more water. If plants are drying out faster than usual and it is difficult to keep them adequately watered, it may be time to place them in larger pots.
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Soil has clay in it, whereas most soilless media or potting soil mixes are composed largely of organic matter, such as peat moss or decomposed bark or compost. Clay retains water and to make up for this characteristic in soilless media, vermiculite is used. Perlite is often used to increase porosity and improve drainage so plants do not remain wet too long. Too much soil in a container-grown plant can result in a hard, compacted medium that does not drain well and is not optimal for plant roots. However, as plant size and container size increase, it is more desirable to add soil to the soilless medium. It can provide better moisture-holding ability and also makes the pot heavier and less prone to tipping because of being top-heavy. Plants that are growing outdoors in containers can also benefit from the improved water-holding ability of soil. They have a limited supply of soil moisture compared to plants growing in the ground. Keep the added soil to a minimum, and remember that the larger the container is, the more soil that can be safely used, but for best results do not exceed a 50-50 blend of soil and soilless media.
Yellowing mushy leaves are an early sign of overwatering. These leaves are often mushy because of the excess water in the cells. They will turn brown and drop off or simply drop off while still yellow.
Allow plants to dry somewhat between watering but do not allow them to remain dry for more than 1 or 2 days. When watering, be sure to moisten the entire root ball. This can be difficult to do, as channels develop through the root ball, and often water runs out through the bottom of the pot before the entire root ball is moistened. A good way to avoid this runoff is to submerge the entire pot in a bucket or other container filled with water. Keep the pot submerged until air bubbles no longer escape.
Place saucers or trays under pots to capture excess moisture. However, excess moisture should be promptly removed so the plants are not standing in it. Some plants do not tolerate wet leaves or watering from the top of the soil. Notable among these are the African violet and cyclamen. Water these plants from the saucers or trays placed under the pots. Allow the moisture to wick upward through the soil. Watch the plants closely to prevent them from remaining in standing water too long. Allow 5 to 10 minutes for the water to wick up from the plant tray. Empty the excess water when moisture has reached the surface of the media.
Proper Container Drainage
Containers used for houseplants must allow complete drainage of water out of the base. Avoid ornamental containers that lack drainage holes. There are two solutions if you must use an ornamental container that lacks at least one hole. One is to set the plastic pot containing the plant inside the ornamental pot. Remove the plant when watering, to allow excess water to drain completely away. The other solution is to drill at least one hole in the base of the ornamental container. If the hole in the base of the container is too large and permits soil to escape from the pot, you may place a piece of pottery shard or medium-mesh screen over the hole.
The quality of potting soil purchased at garden centers and nurseries varies greatly. Some media are excellent all-purpose mixes, whereas others are muck-like. The latter may appear dark in color and may even be crumbly when dry, but when wet, they become a clayey mass with small pores that do not drain well. They may lack a variety of particle sizes and thus are poor media for use in container-grown plants.
The ingredients in potting soil, or soilless medium, as it is sometimes called, should be labeled on the bag. The major ingredients used in good-quality potting soil are peat moss and/or compost, perlite, and vermiculite. Peat moss and compost are organic media that provide aeration and a large surface area for moisture and nutrient storage. Perlite is an inorganic medium created by heating a mineral that is of volcanic origin. Perlite particles are relatively large and provide drainage in soilless media. Vermiculite is a layered clay that swells like an accordion when water is available. It has also been heated to high temperatures. It retains water well, while making moisture easily available to plant roots.
The ratio of different soilless media ingredients determines how well-draining and how moisture-retentive it will be. Commercial mixes are available for different purposes. Seed-starter medium has higher amounts of vermiculite. Mixes for larger container plants may include larger particles, such as partially composted bark. These provide better drainage and reduce compaction that can occur with smaller particles over time.
Fertilization requirements of houseplants vary, depending on whether or not they bloom, how fast you want them to grow, the media in which they are growing, and the species grown. Fertilizers contain three main ingredients: nitrogen, phosphorus, and potassium. These and other plant nutrients are discussed in detail in chapter 6. Nitrogen contributes to green vegetative growth and is helpful for plants that are grown for their foliage. Phosphorus aids in flower and fruit development and is used to encourage blooms and fruiting. Special bloom-enhancing fertilizers often have an increased level of phosphorus compared with levels of nitrogen and potassium, such as 10-60-10, 3-12-6, and so on. Potassium is useful for root growth, but this is not normally a concern with houseplants as it is for some vegetable root crops.
Houseplants typically do not require a great deal of fertilizer. This is primarily because they are grown under low light levels. If you keep in mind the fact that the main limiting factors for growth are light, temperature, water, C[O.sub.2], and fertilizer, then it makes sense that plants grown under low light conditions are not going to require much fertilizer or water either. Therefore, if you fertilize heavily, the result may be salt buildup and burning of the roots caused by overfertilization. A good rule of thumb for most houseplants is to fertilize during the growing season and allow for a rest period in the off season. However, if conditions inside are fairly constant throughout the year, then occasional weak fertilizing will suffice.
Some exceptions to the rule of fertilizing lightly are flowering plants that may require higher levels of fertilizer for flowers to form, such as geraniums, or plants that flower in response to higher levels of phosphorus, such as African violets. Other plants may flower better when grown under low-fertilization conditions, whereas still others flower in response to higher light levels. The latter plants will flower more often under moderate to high light levels than under low light levels, but the foliage will be fine either way.
Because houseplants tend to remain in the same container for years, there are two common types of fertilizer: water-soluble and time-release capsules. Water-soluble fertilizers may be applied with watering, and the amount can be adjusted depending on the light level. The usual recommendation is to add 1 teaspoon per gallon of water and water with this solution every 2 weeks. Time-release fertilizers are applied at rates determined by the size of the pot. Common rates include 1 teaspoon for a 6-inch pot and 1 tablespoon for an 18-inch pot. Cacti and succulents may require only half the usual rates. Time-release capsules are designed to last for several months, although more fertilizer will be released as watering and temperatures increase.
GREENHOUSES AND OTHER STRUCTURES
Greenhouses provide a sheltered environment that can extend the growing season or allow for year-round enjoyment of foliage plants and flowers. Greenhouse structures range from simple plastic-covered hoop houses, to three-sided home additions, to high-tech automated, integrated, computer-controlled feats of engineering. The options for greenhouse structures are as diverse as one's imagination and ability to adapt the available materials and technology. Of course, predesigned kits are available for many different situations. Although a greenhouse addition can be a costly undertaking for the average homeowner, the resultant ability to grow plants throughout the year and to extend the growing season can provide much pleasure and enjoyment. This section will focus on greenhouses for the typical homeowner rather than state-of-the-art greenhouses available for commercial production.
One important factor in deciding what kind of structure to build onto the home is energy use and cost. It is more efficient to attach a greenhouse to an existing structure than to build a free-standing unit. Whereas the obvious assumption is that heating costs will be high in winter, cooling costs in summer or in warmer climates could also be quite high. The goal of a good design is to minimize these costs. Some ways to do that include using an earth-sheltered design, collecting solar energy in water barrels or containers of rocks, providing heat close to the plant root zone rather than heating the air, and proper orientation of the structure.
A greenhouse can be oriented either east and west or north and south. In general, at latitudes below 40[degrees] the orientation is not crucial to good growing conditions. However, north of this latitude, an east-west orientation is recommended. This orientation maximizes sunlight, particularly during the colder months when the sun is lower in the sky. The angle of the south-facing roof should be designed to maximize sunlight during the shortest day of the year. This angle changes with location (see chapter 7 and Fig. 7-13).
Heating and Cooling
A home greenhouse can be heated with passive solar heat, with a space heater, or with hot water from a dedicated hot water heater. The hot water may be piped into the ground or underneath beds. There are even specially designed mats for running hot water under plants directly on the bench. Solar energy can be collected in water barrels, and home greenhouses can be partially earth-sheltered to reduce heating costs in winter.
Cooling can be active or passive. Passive cooling is accomplished using vents. Active cooling is accomplished either with vents and fans or with evaporative cooling coupled with the use of vents and fans. The evaporative cooling unit is a separate unit that would be installed on the ground outside the greenhouse. It is more effective in dry climates than in humid ones, as it works on the principle of adding moisture to the air to absorb heat.
Because the basic concept at work in greenhouses is the trapping of light energy that becomes heat energy inside them, one effective technique for cooling the greenhouse is to reduce the amount of light coming in. This is done by covering the entire structure with a woven shade-cloth material. Shade-cloth is available in different levels of shading, from 22% to 90%. Instead of placing it over the entire structure, it can be used over individual benches. Cooling can also be achieved using a mist or fog system. This is a type of evaporative cooling, so the lower the humidity, the better it works.
If you are going to start seeds in the greenhouse or grow plants in small pots, you will want benches that can bring the plants to about waist level. The benches should be wide enough to reach across, or about 3 to 4 feet wide. If you are growing woody plants in larger pots, then benches may not be needed. If you wish to grow plants in-ground, then growing beds would be more appropriate. With proper planning, it is possible to design the greenhouse for a combination of plant sizes, having benches for some and ground beds for others.
People often have dreams of growing tomatoes or other favorite foods in their greenhouse on a year-round basis. This is possible if there is ample light in your region. However, tomatoes, in particular, are a high-light plant and will probably require supplemental lighting in winter in low-light regions. Although the plants may grow throughout the winter, they probably will not produce flowers or fruit without supplemental lighting. Other plants also have high light requirements. Many flowering plants, including geraniums, bougainvillea, roses, and others require supplemental lighting to flower out of their usual season. See chapter 7 for a discussion of lighting. Supplemental lighting for plants is provided with specially designed, high-intensity discharge (HID) lamps. Incandescent lamps may be useful for photoperiodic plants but are not adequate to provide supplemental lighting for plant growth. Fluorescent lamps can be quite useful as supplemental lighting, although they do not provide as great a range of wavelengths as HID lamps do.
Although many people prefer to water their plants manually because they can watch for changes or problems, automatic watering systems are available and fairly easy to set up. They can save time by allowing all the plants on one system to be watered simultaneously. Pots can be individually watered using spaghetti tubing that attaches to a main water hose, or an entire bench or bed can be watered with sprinklers on a mist system. An advantage of watering plants individually is that the water goes directly where it is needed, so less water is used or wasted. If plants require different amounts of water, zones can be created with a separate watering system for each. For example, plants in different sized pots, seedlings and mature plants, or those in ground beds will require a different amount of water. Also, in a very large system in which water pressure is an issue, it may be necessary to water plants in individual zones, one at a time.
Watering systems can be set up on a timer, but this is only recommended if the plants use a predictable amount of water consistently. Because conditions change daily and throughout the day, it is preferable to turn on the system after checking the plants and determining that they require watering. Proper watering occurs when 10% to 15% of the water applied drains from the bottom of the container. This helps to ensure that the entire root ball is wet. Regardless of whether watering is manual or automatic, it should be done early enough in the day to allow excess moisture to evaporate, especially from the leaves. If plants in a greenhouse environment are watered later in the day, they may remain wet throughout the night, providing optimal conditions for fungal growth. On very hot days and especially with smaller plants, it may be necessary to water more than once each day.
Bottom heat is beneficial for seed germination and for rooting cuttings. Electric mats that plug into an outlet or a thermostat are easily obtained from greenhouse supply companies. Hot water tubing is also available. Mats that allow for circulation of hot water through a series of built-in channels are a low-cost, convenient way to provide bottom heat. These mats are connected to a hot water heater that can be dedicated to this purpose, if desired.
For all the different systems--heating, cooling, moisture, lighting, and bottom heat--sensors and controls will prove to be quite convenient. Thermostats may be used for heating and cooling, and moisture sensors can be used for turning on mist systems. Timers can be set up for watering.
Other Ways of Creating a Greenhouse Environment
If you do not have the space, time, or money to have your own home greenhouse, but you still want to start seeds early or overwinter plants that are not quite hardy in your region, one alternative that many people find practical is the cold frame. The top lid of the cold frame is glass, polycarbonate sheets, plastic film, or other glazing material that is oriented at an angle to face the sun in spring, when the cold frame will be used. The sides can be easily constructed of lumber or another material. Foam insulation board can be useful for lining the inside walls and helping to contain the warmth that enters through the glazing on top. Alternatively, hay bales can be used to form the walls. Hay or straw may also be placed inside the cold frame to provide insulation to the containers the plants are in. Manure and compost, as they decompose, generate a lot of heat. It is possible to harness this heat inside a cold frame to provide the necessary bottom heat for starting seeds or rooting cuttings. Something as simple as an old window placed on top of hay bales that have been arranged to form a square or rectangle, can provide an inexpensive and practical cold frame.
PLACING PLANTS OUTDOORS AND BRINGING THEM BACK IN
The types of plants that people place outside in summer but must bring indoors for the winter include tropical foliage plants, orchids, and other tender flowering plants. One should be aware of certain factors when bringing plants indoors after they have been outdoors for several months. One crucial factor is light intensity. Outdoors in summer, plants receive high light intensity. Even plants that have been placed in a shady location may receive more light outside than they will when they are moved indoors. Thus, many plants will stop growing or will grow much more slowly after being moved inside. If the plant is a high light-requiring plant, it is best to provide the highest amount of light available indoors. This may mean placing the plants in a sunny window or providing supplemental lighting. If the plants have a dormant season, during which they should not be watered, this is a good time to begin reducing the amount of water applied each week.
Plants that have been outside may have insect infestations. Be sure to check thoroughly for mites, aphids, snails, and other pests before bringing the plants indoors. Spray plants with a mild soap solution to clean them and remove any pests. If you actually see pests or signs of pest damage, treat the plants with a pesticide before bringing them indoors.
When plants are outside, they are subjected to fluctuating day and night temperatures, whereas the temperatures in a home fluctuate much less. It is not necessarily desirable to provide widely fluctuating temperatures for plants. The best practice for growing plants indoors is to learn the optimal conditions for a particular plant and provide the conditions as closely as one is able. After having been outside, many plants have developed a lot of good growth and have been able to store excess carbohydrates that will help them get through the less than optimal conditions indoors during the winter months. Temperatures indoors that fluctuate less can be a helpful factor for plants because the relatively cooler day temperatures will benefit photosynthesis as well as allowing stomates to remain open, and respiration will be slower at the cooler night temperatures. In summary, the winter months are more or less a resting time when plants will maintain the status quo or perhaps use some of their reserve carbohydrates but will not grow.
REPOTTING A HOUSEPLANT
When a plant has outgrown its container, there are several signs. First, it becomes increasingly difficult to keep it well watered. Because the roots fill the pot and may be encircling it, they quickly absorb any water provided. Second, because the plant is probably drying out often and staying dry too long, the leaves begin to turn brown or leaf margins turn brown because they are necrotic. Finally, roots may be seen emerging from drainage holes in the bottom of the pot.
When you attempt to remove the plant from the pot, a root-bound plant will come out with its entire root ball intact. If the roots have begun encircling the pot, it is very important to prune them or slice through the outer ring of roots to stop this habit. Otherwise, after repotting the new plant, the roots will still follow their circular habit and will girdle the plant or stunt its growth. If the roots are not too tightly bound, it is not necessary to disturb them, but simply place the entire root ball into the next size container. If the roots have grown to a tight mass, then gently tease them out with your fingers, massaging them free from the mass so that they will grow in a downward direction once they are in the new container.
When repotting plants, it is common to place them in the next size container rather than jump to a much larger pot. Another possibility with plants that can be divided is to divide the plant and grow each new plant in the same size of container as the original. As is usual for container-grown plants, be sure the containers you use have one or more drainage holes. Do not add rocks or gravel to the bottom of the pot, unless you wish to create a shallower root environment than the container provides.
To plant in the new container, place some potting soil into the center of the pot. Set the new plant into place, and fill in around the edges with potting soil. Allow room for about 1 inch at the top of the pot for watering. This will prevent soil spillage during successive watering. Set the pot on a tray to catch excess water. Place the plant in the desired location.
Indoor plants can be easy or challenging to grow. Many have adapted to a shady environment with little temperature fluctuation, so they are well-suited to indoor culture. However, flowering plants and other more demanding plants can also be grown indoors. It is necessary to understand where plants originated to provide an optimal environment and to be successful in growing them indoors. Indoor plants provide benefits beyond aesthetics; in addition to generating oxygen, some of them remove common indoor pollutants from the air.
Lighting is a crucial factor in providing the proper environment for indoor plants. Some of them only require a low level of lighting and may not do well with direct sunlight; others require some direct sunlight during the day. Humidity can affect indoor plants. Humidity inside a home is usually low because of heating and cooling systems.
Plant containers must provide drainage, and they should be appropriately sized. Shallow containers tend to stay moist longer than deeper ones. Small plants should be grown in small containers, and large ones should not be allowed to become root-bound. A well-draining medium is desirable for most container-grown plants. Overwatering and underwatering are the two main reasons for death of indoor plants, and this is often directly related to container size and media type.
Fertilizer is usually provided at a low level, unless a lot of growth is desired, and the proper environmental conditions can be provided to support it. Greenhouses provide a space in which to grow plants while maintaining better control over environmental factors such as light, humidity, and temperature. They can be quite expensive, but provide the serious hobbyist a rewarding place to pursue their horticultural interests.
* Force bulbs and grow them indoors.
* Grow a plant in the classroom. Select a plant on the basis of available lighting in the room. i.e., fluorescent lights, windows, and so on. Also take into consideration the high and low temperatures. Is it humid in your room or dry?
* Grow a plant at home or in your dormitory room. Select the plant on the basis of the available light level and space. How can you provide adequate nutrition and water to the plant?
* Write a research paper comparing the differing requirements for three different types of plants that can be grown indoors. Select from cactus, succulent, fern, foliage plant, or indoor flowering plant. Include information on temperatures, humidity, soil/soilless media, fertilizer recommendations, level of watering, and light requirements.
1. Some houseplants can remove these indoor air pollutants:--, --, and --.
2. Compare the amount of light available indoors depending on the orientation of windows: north, south, east, and west.
3. What is forcing of bulbs and how does it work?
4. Discuss ways to increase moisture retention in soilless media.
5. Discuss ways to improve drainage in soilless media.
6. What is a sign of overwatering?
7. Describe the correct method of watering houseplants.
8. Discuss the effect of soil from outdoors in container-grown plants.
9. Discuss the advantages of fertilizing houseplants above a minimal amount.
10. What is glazing on greenhouses?
Bonsai Clubs International. (n.d.) What is Bonsai? Retrieved July 19, 2005, from http://www.bonsai-bci.com/whatis. html.
Clarke, G. (1997). Indoor plants. Pleasantville, NY: Reader's Digest.
De Hertogh, A. A. (1977). Holland bulb forcer's guide (2nd ed.). New York: Netherlands Flower-Bulb Institute.
Lancaster, R., & Biggs, M. (1998). What houseplant where. New York: Dorling-Kindersley.
Prescod, A.W. (1992). More indoor plants as air purifiers. Pappus, 11, 4.
Whiteside, K. (1999). Forcing, etc. the indoor gardener's guide to bringing bulbs, branches and houseplants into bloom. New York: Workman.
Gus De Hertogh: Pioneer of Bulb Forcing
The practice of forcing bulbs to obtain flowering at a specified time is a relatively modern phenomenon, with thanks mainly to Dr. Gus De Hertogh. Dr. De Hertogh was a researcher in Michigan at a time when the Holland bulb industry needed help in learning how to market their product to the United States. The main problem was forcing the bulbs under American conditions. Through his research, he devised protocols for shipping bulbs, handling them after they arrived from Europe, cooling them, and then forcing them for greenhouse production. His results were a great boon for the bulb industry and led to the publication of the information in the Holland Bulb Forcer's Guide, the authority on bulb production and forcing. Dr. De Hertogh has received many awards and commendations for his research. The rest of us have been rewarded with the beauty of all the tulips, narcissus, hyacinths, and other bulbs that we can now force at home ourselves. They are also available in florist shops when the winter cold seems never ending, bringing special and much appreciated liveliness and color into our homes.
The technique of bonsai originated in Asia as a means of imitating plants in nature that have usually grown in adverse conditions that resulted in the plant's growth being stunted and misshapen. Bonsai means tree-in-a-pot in both Japanese and Chinese. The technique involves a great deal of shoot and root pruning, coupled with growing the plants in root-restricted environments. Most often woody plants are used in bonsai. Wiring is used to give the plants artistic, unusual shapes so that they appear gnarled or weeping or to give branches specific shapes.
Some of the classical shapes for bonsai include informal upright, formal upright, broom, slanting, windswept, cascade, twin trunk, multiple trunk, raft and group, clasped to rock, and literati (bunjin) form. Each form has specific rules about trunk shape and size, branch angle, and even root characteristics (Fig. 12-8). Special pruning tools are used to achieve desired shapes and to direct growth. Pruning is not constant but occurs at specific times of year during the growing cycle.
Bonsai plants can be started from seed, from cuttings, and from plants purchased at nurseries or transplanted from the wild. They can also be purchased in a bonsai form already.
The beginning student of bonsai should seek professional guidance and detailed information, as it is necessary to fully understand and appreciate the special needs required by bonsai plants before one can achieve success. Table 12-5 lists some plants that are successfully used as bonsai. The following are some tips and guidelines for growing and caring for bonsai plants.
Bonsai trees are normally grown outdoors, and they may be deciduous or evergreen. Both temperate and tropical plants are used. For tropical plants, it is necessary to bring them indoors during cold weather to protect them from freezing. However, bonsai plants do not otherwise survive well indoors for several reasons. One is that indoor lighting is inadequate for plant growth. Remember that most houseplants have evolved in areas of low light, such as the understory in rainforest areas. Other plants that can be grown indoors require supplemental lighting for normal growth and flowering. Another reason many bonsai trees do not do well as indoor plants is because of their requirements for cool temperatures and the shortening photoperiod in fall that signal dormancy, followed by chilling in winter that is required by the flowering buds of many of these plants.
For tropical bonsai species that will be grown indoors for most of the year, several conditions should be met to maintain optimal growth. One of these is adequate lighting. This includes both high light levels and light of the proper wavelength (see chapter 7 for a discussion of this topic). High-intensity discharge and fluorescent lamps can provide these. Light requirements may be met by a sunny window, but whether light will be adequate depends on the number of hours of sunlight provided as well as the intensity of the light. However, on cloudy, short days light is usually inadequate.
Another adverse condition found with indoor climate control systems is low humidity. Both air conditioning in summer and heating in winter dry the air inside a home to as low as 20% to 30% humidity. Avoid placing plants in drafty locations where moisture will be moved away from the leaves, causing the plant to dry out too fast. Use a pebble tray to keep some water around the vicinity of the plant (see Fig. 12-5). Also, a humidifier can increase the humidity around the vicinity of the plant.
Bonsai plants are trained to grow in small spaces, with restricted root balls. The small, shallow containers commonly used for bonsai tend to be poorly draining. Because plants require moisture and oxygen in the root environment, it is necessary to remedy the drainage situation so that both are available to the plant most of the time. The remedy for poor drainage due to shallow depth is to include gravel, sharp sand or perlite in the root media to increase drainage. Good, rapid drainage then leads to the need to water bonsai plants regularly to ensure adequate moisture availability. Bonsai plants should be checked at least once a day and watered as needed, allowing the roots to dry slightly between watering, but never allowing the root ball to become completely dry. The top one-half inch or so of the medium should be dry before the plant is watered. The length of time required for this to occur will vary depending on temperature, air movement, humidity, and growth of the plant.
[FIGURE 12-8 OMITTED]
In general, the best time of day to water bonsai is in the morning. Watering in the morning ensures that plants have the water they require during the heat of the day and during the main growth period of the day. It also allows plants to dry adequately before night and reduces the incidence of fungal growth that often occurs under cool, moist conditions. Provide enough water so that excess drains from the bottom of the pot. This helps to ensure that the entire root ball has been wetted.
Dr. Marietta Loehrlein currently teaches horticulture classes at Western Illinois University in Macomb, Illinois. She earned both her bachelor's degree in Agronomy and her master's degree in Plant Genetics at The University of Arizona. Her master's research project was concerned with germination problems associated with triploid seeds, from which seedless watermelons grow. Following that she worked for 5 years in a breeding and research program for Sunworld, International near Bakersfield, California. She worked with peaches, nectarines, plums, apricots, and cherries. Then she returned to school to earn her Ph.D. in Horticultural Genetics at The Pennsylvania State University. Her Ph.D. research focused on flowering processes in regal pelargonium (also called Martha Washington geraniums). While at The Pennsylvania State University, she bred a new cultivar of regal pelargonium, "Camelot." At Western Illinois University, Dr. Loehrlein teaches nine courses: Greenhouse and Nursery Management, Introductory Horticulture, Landscape Design, Landscape Management, Home Horticulture, Plant Propagation, Turf Management, and two courses in Plant Identification.
TABLE 12-1 COMMON NAME GENUS/SPECIES TEMPERATURE Foliage Aluminum plant Pilea cadieri 75-85 Arrowhead plant Syngonium 75-85 Asparagus fern Asparagus 75-85 Baby tears Helxine 45-65 Begonia Begonia 75-85 Bromeliad Aechmea 60-75 Bromeliad Guzmania 60-75 Bromeliad Neoregelia 70-80 Bromeliad Nidularium 65-75 Cabbage palm Cordyline 60-85 Caladium Caladium 70-75 Calathea Calathea 60-64 Cast-iron plant Aspidistra elatior 75-85 Chinese evergreen Aglaonema 75-85 Cleyera Cleyera 55-70 Coffee Coffea arabica 60-70 Coleus Coleus 75-90 Croton Codiaeum 65-85 Date palm Phoenix spp. 65-70 Dracaena Dracaena 60-85 Dumb cane Dieffenbachia 58-64 English ivy Hedera 65-78 European fan palm Chamaerops 50-75 False aralia Dizygotheca 60-75 False castor oil plant Fatsia 50-70 Fig Ficus 55-60 Fittonia Fittonia 65-75 Golden pothos, Epipremnum aureum 60-80 devil's ivy Howe's palm Howeia 55-65 Japanese laurel Aucuba japonica 75-85 Maranta Maranta 60-70 Norfolk Island pine Araucaria 40-50 Palm Chamaedorea 57-70 Peperomia Peperomia 64-68 Philodendron Philodendron 58-64 Purple velvet leaf Gynura 75-85 Screw pine Pandanus 68-72 Spider plant, airplane Chlorophyllum 50-75 plant comosum Spiderwort Tradescantia 50-60 Swiss cheese plant Monstera 58-65 Umbrella plant Cyperus 55-68 Umbrella plant Schefflera 65-80 Wandering Jew Tradescantia zebrina 60-70 Yucca Yucca 45-65 Zebra plant Aphelandra 75-85 Ferns Bird's nest fern Asplenium nidus 65-75 Boston fern Nephrolepis exaltata 60-75 Boston fern Nephrolepis exaltata 60-75 'Bostoniensis' Brake fern Pteris spp. 55-65 Button fern Pellaea rotundifolia 60-75 Climbing bird's nest Polypodium punctatum 60-75 fern Creeping moss Selaginella 55-60 Deer's foot fern Davallia canariensis 60-75 Hart's tongue fern Phyllitis 60-75 scolopendrium Holly fern Cyrtomium falcatum 50-75 Holly fern Poloystichum tsus- 55-65 simense Maidenhair fern Adiantum raddianum 65-75 Maidenhair fern Adiantum tenerum 65-75 Palm-leaf fern Blechnum capense 60-64 Rabbit's foot fern Polypodium aureum 55-60 Stag's horn fern Platycerium 60-75 bifurcatum Tree maidenhair Didymochlaena 60-75 truncatula Flowering Plants Achimenes Achimenes 55-60 African violet Saintapaulia ionantha 65-75 Azalea Rhododendron indicum 50-60 Basket vine Aeschynanthus 65-70 Billbergia Billbergia spp. 70-80 Bird of paradise Strelitzia reginae 60-85 Bottlebrush Callistemon citrinus, 45-65 Callistemon speciosus Bougainvillea Bougainvillea 50-80 Bouvardia Bouvardia x domestica 55-60 Brassia Brassia 65-70 Bromeliad Tillandsia cyanea 75-85 Bromeliad Vriesia splendens 65-70 Browallia Browallia 65-75 Brunsfelsia Brunsfelsia 55-60 Calla lily Zantedeschia 50-65 elliottiana Camellia Camellia japonica, 50 Camellia sinensis Cape primrose Streptocarpus x 65-70 hybridus Chenille plant Acalypha 60-65 Cineraria Cineraria grandiflora 60-70 Coleus Coleus fredericii, 75 Coleus thyrsoideus Crossandra Crossandra 64 infindibuliformis Cyclamen Cyclamen persicum 46-50 Cymbidium orchid Cymbidium spp. 45-54 Dendrobium orchid Dendrobium spp. 75 during growth, 46-50 during dormancy Egyptian star cluster Pentas 60-75 Fibrous rooted begonia Begonia semperflorens 65-70 Flame plant Anthurium scherze- 64-68 ranum, Anthurium andreanum Florist's hydrangea Hydrangea macrophylla 40-46 Flowering maple Abutilon 57-63 Fuchsia Fuchsia hybrids 55-75 Gardenia Gardenia augusta 60-64 Glorybower Clerodendron spp. 55-75 Glory lily Gloriosa 60-66 Gloxinia Sinningia regina, 60-70 Sinningia speciosa, Sinningia hybrids Hoya Hoya carnosa, Hoya 50-54 bella Impatiens, touch-me- Impatiens balsamina 68 not, 'Busy Lizzie' Ivy geranium Pelargonium peltatum 60-75 Jasmine Jasminium 55-75 Kaffir lily Clivia miniata 55-60 Lollipop plant Pachystachys lutea 59 Miniature rose Rosa chinensis var. 50-85 indica Mum Dendranthema 60-70 grandiflorum Odontoglossum Odontoglossum 50-60 Oncidium orchid Oncidium Varies by species Ornamental chili Capsicum 60-70 pepper Pansy orchid Miltonia spp. 50-60 Passion flower Passiflora spp. 45-65 Peace lily Spathiphyllum 60-75 Periwinkle Catharanthus roseus 70-80 Persian violet Exacum affine 55-70 Pocketbook plant Calceolaria 50-54 Poinsettia Euphorbia pulcherrima 64-68 Pomegranate Punica granatum 45-75 Regal geranium Pelargonium 50-75 domesticum Rose mallow Hibiscus rosa- 54-59 sinensis Shrimp plant Drejerella 54-59 Slipper orchid Paphiopedilum 54-59 Tuberous rooted Begonia x 75-85 begonia tuberhynrida Wood sorrel, Oxalis rubra 54-57 shamrock Zonal geranium, Pelargonium x 75-85 garden geranium hybridum Cacti and Succulents Parodia 45-75 Aloe Aloe vera, Aloe 40-70 variegata Barrel cactus Echinocereus spp. 65-85 Bishop's cap cactus Astrophytum ornatum 40-70 Christmas cactus Schlumbergera 55-65 bridgessii Easter cactus Rhipsalidopsis 54-80 Euphorbia Euphorbia 65-85 pseudocactus Gasteria Gasteria liliputana 50-54 Gymnocalycium Gymnocalycium spp. 70-85 Haworthia Haworthia spp. 50-54 Hens and chicks, Sempervivum 35-47 houseleek Jade plant Crassula argentea 50-60 (Crassula portulaca, Crassula arborescens) Kalanchoe Kalanchoe spp. 50-75 Living stones Lithops 40-70 Mesems, living stones Argyroderma 40-70 Moonstones Pachyphytum oviferum 45-65 Neoporteria Neoporteria 45-75 (Eriosyce) spp. Old man cactus Cephalocereus senilis 59-75 Painted lady Echeveria derenbergii 45-65 Peanut cactus Chamaecereus 28-65 sylvestri Pincushion cactus Mammillaria spp. 45-75 Prickly pear Opuntia 45-95 Queen Victoria Agave victoria- 40-70 century plant reginae Snake plant, mother- Sanseveria 59-80 in-law's tongue trifasciata Stonecrop Sedum spp. 46-75 Thanksgiving cactus, Schlumbergera 54-80 false Christmas truncata cactus COMMON NAME LIGHT MOISTURE Aluminum plant Medium low Moist Arrowhead plant Bright, indirect Moderate, humid Asparagus fern Medium Moderate Baby tears Indirect Moderate Begonia Outside in summer Medium to moist Bromeliad Indirect Moist Bromeliad Bright, indirect; Moist outside in summer Bromeliad Bright, indirect Moist Bromeliad Partial shade Moist Cabbage palm Bright, indirect Moist Caladium Bright indirect Moist Calathea Bright indirect Moist, humid Cast-iron plant Low Medium Chinese evergreen Indirect, north Medium window Cleyera Semishady Moist Coffee Semishady Moderate Coleus Bright indirect Moist Croton Bright indirect Moist Date palm Outside in summer Moist Dracaena Bright, indirect Moist Dumb cane Bright, indirect Moist light English ivy Bright, indirect; Moderate outside shade in summer European fan palm Bright Moderate False aralia Bright, indirect Moderate False castor oil plant North window or Moist shade Fig Bright, indirect Moist Fittonia Bright, indirect Moist, humid Golden pothos, Full to partial shade Moderate devil's ivy Howe's palm Shady Moderate dry Japanese laurel Low Medium Maranta Bright, indirect Moderate Norfolk Island pine Shade Moderate to light Palm Bright indirect Moderate Peperomia Bright, indirect Dry, humid Philodendron Bright, indirect Moist Purple velvet leaf Sunny Moderate Screw pine Bright, indirect Moist Spider plant, airplane Low to high Low to moderate plant Spiderwort Indirect Moderate Swiss cheese plant Indirect; outside Moist shade in summer Umbrella plant Well-lit Wet Umbrella plant Sun Moderate Wandering Jew Bright Moderate Yucca Sunny; outside in Moderate dry summer Zebra plant Good, indirect Moist Ferns Bird's nest fern Shady Humid; moderate; dry in winter Boston fern Indirect sunlight Humid; moderate; dry in winter Boston fern Indirect sunlight Humid; moderate; dry in winter Brake fern Shady Humid, moist Button fern Good light Humid; moderate; drier in winter Climbing bird's nest Shady Humid; moderate fern Creeping moss Shady Moist Deer's foot fern Shady Humid; moderate; dry in winter Hart's tongue fern Shady Humid; moderate; dry in winter Holly fern Shady Humid; moderate; dry in winter Holly fern Shady Humid, moist Maidenhair fern Shady Humid; moderate; dry in winter Maidenhair fern Shady Humid; moderate; dry in winter Palm-leaf fern Shady Humid; moderate; dry in winter Rabbit's foot fern Shady Humid; moderate; drier in winter Stag's horn fern Bright, indirect Humid; moderate; sunlight drier in winter; use tepid water Tree maidenhair Shady Humid; moderate; dry in winter Flowering Plants Achimenes Bright, indirect Humid, moist African violet Bright, indirect Moderate: water from below with tepid water Azalea Indirect, partial Moderate, humid shade Basket vine Partial shade Humid, moderate moisture Billbergia Bright, indirect Humid; moderate; drier in winter Bird of paradise Bright, indirect; Moderate outside in summer Bottlebrush Bright light Moderate Bougainvillea Outside in summer; Moderate; drier in bright light in winter winter Bouvardia Bright, indirect Moderate; drier in winter Brassia Bright, indirect Humid; moderate moisture Bromeliad Bright Humid, moist Bromeliad Bright, indirect Humid, moist; lukewarm water Browallia Good Moist Brunsfelsia Half-shady; more Humid; moderate; light in winter drier in winter Calla lily Bright; outside in Moist; dry in summer dormancy (after flowering) Camellia Semi-shady; outdoors Moderate; less in in summer summer; use lukewarm water Cape primrose Bright, indirect Moderate; tepid water Chenille plant Bright, indirect Moderate Cineraria Shade or indirect Moist light; outside in summer Coleus Bright, indirect Moist, drier in summer Crossandra Good, indirect light Humid; moist during growing season, moderately after flowering; use lukewarm water Cyclamen Bright, indirect Moist during growing season, dry while dormant Cymbidium orchid High, indirect light Moist in summer, but allow to dry between waterings; drier in winter Dendrobium orchid Bright, indirect Humid and moist sunlight while growing, drier during dormancy Egyptian star cluster Bright, indirect Moderate; water sparingly after blooming Fibrous rooted begonia Bright, indirect Humid, moderate Flame plant Shady Humid Florist's hydrangea Shady; outside in Moist summer in a shady location Flowering maple Bright, indirect; Moderate outside in summer Fuchsia Bright; outside in Humid; moist; drier summer in winter Gardenia Bright Humid; moderate watering; use tepid water Glorybower Indirect sunlight Humid, moist, drier in winter Glory lily Bright, indirect Moderate Gloxinia Bright, indirect Moist, lukewarm water; do not spray leaves Hoya Bright, indirect Moderate, less in winter Impatiens, touch-me- Bright, indirect; Moist not, 'Busy Lizzie' outside in summer in a shady location Ivy geranium Bright, direct; Moderate outside in summer Jasmine Bright, indirect Moist; drier in winter Kaffir lily Bright, indirect Moist but allow to dry between waterings; drier in winter Lollipop plant Bright, indirect Moist, keep drier in winter; use tepid water Miniature rose Sunny; outside in Moderate dry summer Mum Outside in summer Moist and fall; indirect light in winter Odontoglossum Shady Moist Oncidium orchid Bright, indirect Humid; water sparingly Ornamental chili Outside in summer; Moderate pepper bright, indirect light in winter Pansy orchid Shady Moist Passion flower Good, direct Moist; drier in sunlight; outside summer in summer Peace lily Shady Moderate Periwinkle Outside in summer; Moist; drier in bright, indirect winter light in winter Persian violet Bright, indirect Moist Pocketbook plant Indirect light Moist Poinsettia Good, indirect light; Moist, but allow to outside in summer dry between waterings; use tepid water Pomegranate Sunny; outside in Moderate summer Regal geranium Bright, direct; Moderate outside in summer Rose mallow Bright, indirect; Moist outside in summer Shrimp plant High light; outside Moist in summer, in summer less in winter Slipper orchid Good Moist; drier in winter Tuberous rooted Bright, indirect Moderate begonia Wood sorrel, Sunny Water sparingly shamrock Zonal geranium, Bright, direct; Moderate garden geranium outside in summer Cacti and Succulents Bright light Moist in summer, but allow to dry between waterings, dry in winter Aloe Bright Moist; dry in winter Barrel cactus Bright; outside in Dry between watering summer Bishop's cap cactus Bright Dry in summer, not at all from fall to spring Christmas cactus Semi-shade in Moist in summer and summer, bright autumn, drier in light in winter winter and spring Easter cactus Semishade in summer, Moist in summer and bright light in autumn, drier in winter winter and spring Euphorbia Bright Moderate to dry Gasteria Bright, indirect Moist in spring and summer, dry in winter Gymnocalycium Partial shade Dry between watering, dry in winter Haworthia Bright, indirect Moist in spring and summer, dry in winter Hens and chicks, Bright light Moderate; dry in houseleek winter Jade plant Bright, indirect Allow to dry between watering Kalanchoe Bright, indirect Dry air; water thoroughly in summer, keep fairly dry in winter Living stones Bright Moist; dry in winter Mesems, living stones Bright Moist; dry in winter Moonstones Bright Moist in summer, dry in winter Neoporteria Bright light Moist in summer, but allow to dry between waterings, dry in winter Old man cactus Good light Light watering in summer, dry in winter Painted lady Bright Moist in summer, dry in winter Peanut cactus Moderate Regular watering in summer, dry in winter Pincushion cactus Bright light Moist in summer, but allow to dry between waterings, dry in winter Prickly pear Bright light; Moderate in summer, outdoors in summer dry in winter Queen Victoria Bright Moist; dry in winter century plant Snake plant, mother- Dim to bright Moderate in summer, in-law's tongue drier in winter Stonecrop Bright light Moderate; dry in winter Thanksgiving cactus, Semi-shade in Moist in summer and false Christmas summer, bright autumn, drier in cactus light in winter winter and spring TABLE 12-2 Plants and the Pollutants They Remove COMMON NAME GENUS/SPECIES POLLUTANT Aloe Aloe vera Formaldehyde Arrowhead plant Syngonium podophyllum Good for formaldehyde Azalea Rhododendron indicum Good for formaldehyde Bamboo palm Chamaedorea seifrizii Excellent for benzene and formaldehyde, good for carbon monoxide Banana Musa oriana Excellent for formaldehyde Bromeliad Guzmania 'Cherry' Excellent for formaldehyde and xylene Bromeliad Neoregelia carolinae Good for xylene 'Perfecta Tricolor' Chinese evergreen Aglaonema modestum Formaldehyde, benzene, toluene, carbon monoxide Christmas cactus Schlumbergera x Formaldehyde buckleyi Dendrobium orchid Dendrobium spp. Acetone, ammonia, chloroform, ethyl acetate, methyl alcohol, formaldehyde and xylene Dumbcane Dieffenbachia Good for formaldehyde maculata Elephant ear Philodendron Excellent for philodendron domesticum formaldehyde English ivy Hedera helix Excellent for benzene, good for formaldehyde, trichloroethylene, carbon monoxide Gerbera daisy Gerbera jamesonii Excellent for benzene and trichloroethylene, good for formaldehyde, carbon monoxide Golden pothos Epipremnum aureum Excellent for carbon monoxide and benzene, good for formaldehyde Heart leaf Philodendron Excellent for philodendron oxycardium formaldehyde Janet Craig Dracaena deremensis Excellent for benzene dracaena 'Janet Craig' and trichloroethylene Lacy tree Philodendron selloum Excellent for philodenron formaldehyde Madagascar dragon Dracaena marginata Excellent for benzene, tree good for formaldehyde and trichloroethylene Mass cane Dracaena fragrams Excellent for 'Massangeana' formaldehyde Miniature umbrella Schefflera arboricola Good for benzene, plant formaldehyde and toluene Mother-in-law's Sansevieria trifas- Excellent for benzene tongue, snake ciata 'Laurentii' and formaldehyde, plant good for trichloroethylene Oyster plant Tradescantia Good for formaldehyde sillamontana Peace lily Spathiphyllum 'Mauna Excellent for benzene Loa' and trichloroethylene, good for formaldehyde, carbon monoxide Peperomia Peperomia obtusifolia Good for formaldehyde Phalaenopsis Phalaenopsis spp. Excellent for orchid formaldehyde and xylene Poinsettia Euphorbia pulcherrima Excellent for formaldehyde Pot mum Chrysanthemum Excellent for trichlo- morifolium roethylene, good for benzene, formaldehyde, and carbon monoxide Spider plant Chlorophytum elatum Excellent for carbon monoxide and formaldehyde Variegated lily- Liriope muscari Excellent for turf 'Variegata' formaldehyde Warneckii dracaena Dracaena deremensis Excellent for benzene 'Warneckii' and trichloroethylene, good for formaldehyde Weeping fig Ficus benjamina Good for formaldehyde TABLE 12-3 Plants and Their Optimal Light Levels COMMON NAME LIGHT LEVEL Flowering maple, chenille plant, lipstick vine, agave, High bamboo, wax begonia, cacti, cattleya orchid, citrus, coleus, 'Tricolor' dracaena, fatshedera, poinsettia, purple velvet plant, variegated ivy, geranium, amaryllis, shrimp plant, kalanchoe, oxalis Maidenhair fern, anthurium, begonia, spider plant, Medium fishtail palm, ti plant, dumbcane, weeping fig, fiddleleaf fig, peperomia, Boston fern, staghorn fern, Swedish ivy, baby tears, wandering Jew, ginger Chinese evergreen, Norfolk Island pine, asparagus fern, Low cast iron plant, parlor palm, devil's ivy, rubber plant, fittonia, philodendron, peace lily, snake plant, arrowhead, bromeliads TABLE 12-4 Specific Requirements for Forcing Bulbs Indoors COMMON NAME GENUS AND SPECIES WEEKS OF WEEKS TO CHILLING BLOOM Amaryllis Hippeastrum None 6-8 Crocus Crocus chrysanthus 15 2-3 Crocus Crocus vernus 15 2 Daffodil Narcissus 15-17 2-3 Fritillary Fritillaria meleagris 15 3 Glory of the Chionodoxa lucilae 15 2-3 Snow Grape Muscari armeniacum 13-15 2-3 hyacinth Grape Muscari botryoides 14-15 2-3 hyacinth Hyacinth Hyacinthus 11-14 2-3 Iris Iris danfordiae 15 2-3 Iris Iris reticulata 15 2-3 Paper whites Narcissus tazetta None 3-5 Siberian Scilla siberica 15 2-3 squill Snowdrop Galanthus nivalis 15 2 Tulip Tulipa 14-20 2-3 Winter Erianthus hyemalis 15 2 Aconite Source: The Netherlands Flower Bulb Information Center, Brooklyn, NY. TABLE 12-5 Some Woody Plants That Work Well for Bonsai COMMON NAME BOTANICAL NAME Azalea Rhododendron spp. Black pines Pinus thunbergii Bougainvillea Bougainvillea glabra Chinese juniper Juniperus x media Flowering crab apple Malus spp. Fukien tea Ehretia buxifolia Gardenia Gardenia jasminoides Ginkgo Gingko biloba Hokkaido elm Ulmus parvifolia 'Hokkaido' Japanese maple Acer palmatum Japanese Zelkova, Japanese Zelkova serrata Keaki tree Kurume azaleas Rhododendron hybrids (Rhododendron kaempferi, Rhododendron kiusianum and Rhododendron obtusum) Lantana Lantana camara Littleleaf boxwood Buxus microphylla 'Compacta,' 'Morris Midget' Little-leaf Cotoneaster Cotoneaster microphylla Norfolk Island pine Araucaria excelsa Olive Olea europa Satsuki azaleas Rhododendron indicum and Rhododendron simsii Serissa, yellow-rim Serissa foetida Singleseed hawthorn Craetagus monogyna Willow leaf fig, Mexicana fig Ficus nerifolia (Ficus salicifolia)
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|Author:||Loehrlein, Marietta M.|
|Publication:||Home Horticulture: Principles and Practices|
|Date:||Jan 1, 2008|
|Previous Article:||Chapter 11: pruning.|
|Next Article:||Chapter 13: vegetable and herb gardening.|