Growing under glass: backyard greenhouses let gardeners enjoy their prized plants year-round. (Gardening).

When Rosemary Grantham wanted to expand her hobby of growing beautiful plants inside and outside of her Ridgeland home, she knew it was time to build a greenhouse. So she and her husband Steve had a 9 x 16-foot structure built in their backyard, using the rear wall of the garage as one of the greenhouse's walls. Now, eight years later, Rosemary continues to work diligently in the greenhouse every day, nurturing more than 150 orchids and a variety of other lush tropical plants in a manner that's almost the way nature intended.

The world of hobby greenhouses is an exciting alternative to seasonal gardening. Gardeners or homeowners who are searching for opportunities to extend their growing season, to grow specific plants or vegetables, or who want the ability to garden year-round will find that greenhouses, as well as other related structures, open endless possibilities.

Greenhouses have been in existence for hundreds of years. They were originally built in Europe and America primarily by the wealthy who desired tropical fruits and flowers which could not grow in colder climates except under glass. In Ortho Books' Greenhouses, which is an excellent guide for beginners, the authors state, "The modern concept of the greenhouse is simple and practical. No longer is it the private domain of the monied class but something that anyone can have for relatively little cost." For homeowners who are high on ideas but short on dollars, this statement makes the dream of a greenhouse a reality for most anyone.

For Rosemary Grantham, having a greenhouse is a way to enjoy nature even in inclement weather.

"I like to be out of doors, and when I cannot be out of doors, I can come here now," she says. "So it's been wonderful for me."

Greenhouses and coldframes are built with the specific intention of growing plants. Solariums and sunrooms, while wonderful spaces to houseplants in homes, are generally lower in humidity than the greenhouse climate. These types of rooms generally have temperature and humidity levels set for the comfort of people as opposed to plants. If possible, a homeowner needs to answer the following questions before rushing out to buy the first greenhouse they see: What is the purpose of this greenhouse? Are there specific plants that I want to raise? Is this for profit or fun? Does the greenhouse need to fit the style of the house or neighborhood? How much work am I willing to do myself? While it's not unreasonable to invest in a greenhouse if these questions aren't answered, having a clearer focus may narrow down the available options.

The first step for any homeowner interested in a greenhouse is to research options that might suit their desires or needs. The market today is filled with multiple options for hobby greenhouses. Greenhouses can be purchased in pre-fabricated kits or can be designed and built by industrious homeowners. Greenhouses can be built from a wide range of materials, including steel, wood, aluminum, glass, plastic, PVC, and polyethylene. They can be freestanding structures or attach to a house or outbuilding. They can be outfitted simply or can be as elaborate as a commercial growing operation. They can be used throughout the entire year or only during specific months. Research is necessary, because the homeowner needs to be aware of the decisions that will need to be made regarding the main components of a greenhouse. Some of the main design features that will need to be considered on the front end are heating and cooling systems, ventilation, water or irrigation, misting systems, shading or covering, and accessories such as shelving units.

With so many different manufacturers and greenhouse companies on the market, the task of choosing a greenhouse can be daunting. The benefits of buying a kit are that it generally can be assembled by nonprofessionals and has been designed with the above-mentioned features in mind. Further suggestions are to solicit the advice of nursery employees, attend home and garden shows which often have displays of greenhouses, and seek the experience of other backyard hobbyists. The Internet and bookstores offer a wide range of research material. Some books recommended for the greenhouse hobbyist on AboutGreenhouses.com are Greenhouses by Ortho Books and Greenhouses for Homeowners and Gardeners by John W. Bartok. A search on the Internet for "hobby greenhouses" will provide more information than a homeowner could ever possibly need.

The cost of a greenhouse can range from $500-$5,000, depending largely on the size and the type of materials. Concrete foundations and glass obviously cost more than gravel and plastic. Other factors that will influence the cost are manufacturers, accessories, and style. Methods of cooling and heating need to be considered when weighing long-term costs.

Grantham says that to be successful, greenhouse gardeners must be dedicated to their hobby.

"When I get up in the morning, it's the first thing I do," she says, noting that many of the plants must be tended to and watered by hand despite the greenhouse's automated systems. "And it can be a rather expensive hobby, but it's very rewarding."

It's also important to seek advice from experienced growers, Grantham says. The expertise of horticulturist Robert Ferguson of Jackson has been a valuable resource to Grantham since her earliest days as a greenhouse gardener. Ferguson cultivates a number of rare and exquisite orchids and other plants in his growing laboratory, and he often has just the right ideas on how to save a plant when it seems to be struggling, Grantham says.

Other alternatives to extending the growing season are coldframes and hotbeds. Coldframes are an inexpensive alternative to a full-scale greenhouse. A coldframe is a simple, unheated box that is placed directly on the ground. There is no heat source inside the box. It is generally slanted and has some type of transparent or semitransparent material such as glass or plastic to allow as much sunlight and heat as possible to be absorbed. Coldframes are an excellent environment for hardening tender annuals in early spring before transplanting them to the garden. They can be used to protect plants that would normally be susceptible to colder temperatures or to give plants a headstart in spring. Coldframes, on the other hand, are not suitable for tender annuals which will not survive colder, unheated nights. They can be built with relatively little expense, especially if a gardener chooses to use discarded windows or scrap materials. As with a greenhouse, a coldframe does need to be vented on warmer days. One wort hwhile accessory for any coldframe is a temperature-sensitive device that detects when to automatically open the top when the temperature exceeds a certain point. Hotbeds, another good alternative for gardeners, are basically coldframes that contain some source of heat to better protect fragile plants.

So what can be grown in a greenhouse? Almost anything. Homeowners can use greenhouses to grow indoor plants, tropicals like orchids, and fruits and vegetables like tomatoes, as well as for sowing seedlings and cuttings and for propagation. As with any plant grown outdoors, greenhouse plants are also susceptible to pests and disease. Some pests like whiteflies become more of a nuisance within the greenhouse environment. Once the growing operation is underway, homeowners should research what types of disease or pests are especially attractive to their specific plants and implement preventative maintenance.

Whatever choices are made, a greenhouse is especially inviting during winter with its lush, green warmth against the dormant landscape. Homeowners will find greenhouses an experience that continues to teach no matter what the season.

For Grantham, it's a natural extension of the love for plants and flowers she's had all her life.

"I've been interested in growing since I was a little girl," she says. "I used to pick flowers from (a neighbor's) yard...now, I have a 4-year-old granddaughter who picks my flowers, and I think it's wonderful."

RELATED ARTICLE: GREENHOUSE GROWING TIPS

Here are a few of the points that every successful greenhouse gardener should remember, according to Rosemary Grantham:

* Humidity. Gravel in the bottom of trays that hold plants, as well as slate floors upon which larger plants sit, help to retain moisture. Grantham's greenhouse also has an automatic misting system that delivers water to the plants three times each day.

* Heat. Especially for plants like orchids, it is important to keep the greenhouse at a consistently warm temperature.

* Cooling. Other plants may prefer slightly cooler temperatures, especially during the hot summer months, so Grantham's swamp cooler system lowers the temperature without drying out the air. In addition, a motorized vent in the ceiling automatically lets hot air escape when the temperature exceeds a set number--in Grantham's case, 78 degrees.

* Air circulation. Several fans are placed around Grantham's greenhouse to ensure good flow of air around the plants.

* Lighting. The transparent walls and ceilings of Grantham's greenhouse allow natural sunlight to work its magic on her plants, even in winter, but when too much sunlight becomes a problem, special screens and blinds filter the light.

TEAPOT TERRARIUM 

If constructing your own greenhouse seems a tad too ambitious, try creating a simple terrarium that will allow you to grow beautiful plants under glass inside your home. For this teapot terrarium, we placed pansies under an old Victorian dome. To make your own terrarium, use any clear watertight container that is large enough to accommodate your plant. Plants such as miniature African violets, small ferns, coffee plants, boxwood, creeping figs, and mosses thrive in this environment. Caring for a plant inside a terrarium is easy: experts recommend neglecting it! Water lightly only after the plant gets dry, once every few weeks; never overwater. Place the terrarium in a bright area but not in direct sunlight. And there's no need to fertilize!