Strategies for summer watering.
* All over the mostly arid West, garden watering is a summer ritual--usually the first chore we tackle in the early morning or after work. On hot days in neighborhood after neighborhood, sprinklers whoosh, hoses gurgle, soaker hoses hiss, and drip systems silently plop their precious cargo into the soil to keep plants lush and green. Gardeners leaving for vacation set automatic controllers or pay a neighbor's kid to handle irrigation.
However diligent we may be about dispensing water, if we don't pay attention to bow we're dispensing it, we waste it. Irrigate plants on windy days, and water can blow away from the intended area before it reaches the ground. Pour the water on faster than soil can absorb it, and rivulets and streams run down driveways and into streets. It's no secret that, in the West, water is liquid gold; in some pay-by-use districts, waste means higher water bills. Here's how to water your garden easily and efficiently.
1. Know your soil
The type of soil you have--sand, clay or loam--influences how fast water penetrates before running off, how of ten plants will need to be watered, and how much water you'll need to apply with each irrigation. Observe what happens to your soil when you wet it.
Clay soils absorb water more slowly than sandy ones do; when water is applied too quickly, it puddles or runs off before being absorbed. Clay soils are slow to dry out; plants that grow in them are particularly at risk of diseases and other problems that result from overwatering. Stretch the time between waterings so plants have a chance to partially dry out. Apply water slowly so it doesn't run off before it can be absorbed.
Sandy soils absorb water quickly without puddling. Compared with plants growing in clay soils, those in sandy soils need water more often but since water penetrates sandy soils faster, you don't need to apply as much. In sandy soils, irrigate more frequently, but don't apply so much water that it will flow through the root zone without stopping.
Loam soils absorb water at an even pace without heavy puddling or runoff. You can recognize loam by picking up a moist handful; when you let go, it holds together but falls apart easily with some gentle prodding.
Most soils are a mixture of clay, sand, and loam. Identify what predominates in your soil and adjust your watering accordingly.
2. Match your irrigation system to your plants
Watering your garden need not be complicated or time-consuming, in fact, easy-to-use hoses or soaker hoses (perforated on one side, or porous overall) may be your best choice for some plants. The list that follows pairs plant groups with the watering methods that work best for each. In-ground sprinklers are certainly best for lawns. Drip-irrigation systems (made of PVC pipe and slender tubing with emitters that deliver water directly to individual plants), managed by automatic controllers can be the most convenient method for irrigating flower beds, rows of vegetables, and even shrubs and trees, especially when you're on vacation. However, both systems must be mapped out and, in most cases, installed before you plant, so the list that follows focuses mainly on manual devices and techniques (building basins and furrows of soil around plants, for instance, to direct water to the roots and help avoid runoff). If you plan to install a larger automated system, it is best to do so before a seasonal planting.
* For a small lawn, hose-end sprinklers can work well.
* Plant in rows with furrows; build basins around large individual plants. Hand-water.
* Use soaker hoses on flat ground.
* Seedlings and vegetables that are flowering or setting fruit need more water than mature ones.
Planning ahead? A drip-irrigation system is the best method. Group plants with similar watering needs.
* Annuals and perennials
* Use soaker hoses or hoses slowly dripping over root zone. Overhead watering may cause flowers to tip or fade; some species are more subject to disease if showered from above.
Planning ahead? For closely spaced beds, choose drip-emitter lines; for widely spaced plants, use individual drip-emitters.
* Ground covers
* Build basins of soil around large, shrubby plants.
Planning ahead? Use in-ground sprinklers; install stationary risers (pop-up types) for plantings more than 1 foot tall, and low-output sprinklers on a slope. Or install a drip-irrigation system for shrubby ground covers.
* Trees and shrubs
* Build basins of soil around shrubs.
* Attach a deep-root irrigator to the end of a hose and inject water into the soil near a tree's roots.
* Soaker hoses work well for occasional deep watering of established trees. Lay them on flat ground; wrap them around the tree several times--starting a few feet out from the trunk and ending just beyond the drip line.
Planning ahead? Low-volume systems with drip-emitters or micro-sprinklers (miniature sprayers) are most efficient, especially on slopes.
* Build basins of soil around the plants to direct hose water to roots.
* On level ground, snake soaker hoses around plants.
Planning ahead? Install in-ground sprinklers with flat-head sprayers (on short risers, these send the spray out straight, rather than up, where it can wet the foliage); run them early so leaves will dry by midday. Or, for closely spaced bushes, install a drip-irrigation system with a drip-emitter line and individual drip-emitters.
* Natives and unestablished drought-adapted plants
Warm, moist soils can be lethal to many native plants and to those of Mediterranean origins, especially in poorly drained soil.
* If plantings are less than a year old, use ooze-type soaker hoses at low pressure, very early or late in the day when soil is cool.
Planning ahead? Use low-flow drip-irrigation with a manual shutoff valve for the first year or so, until plants are established. After that, natives and drought-adapted plants need little to no water beyond rainfall.
* Container plants
* Hand-water gently, using a hose fitted with a wide nozzle.
* Submerse hanging baskets and small pots for half an hour in tubs of water to saturate soil.
* Install drip tubing to water pots for two to five minutes, several times a day. Simple drip-irrigation kits for container plantings are sold at garden centers and nurseries.
3. Irrigate plants to the correct depth
Apply enough water to wet the entire root zone and to encourage deep rooting. Deeper roots are better able to withstand periods of drought; shallow watering, on the other hand, leads to shallow roots and plants that are susceptible to drought and strongly affected by fluctuating temperatures. (Properly irrigated, roots of lawn grasses grow about 6 inches deep, shrub roots about 12 to 18 inches deep. Most tree feeder roots, even of large trees, are within the top 2 feet of soil; they extend well beyond the tree's drip line.) How can you tell how deep water is penetrating? Push a stiff metal rod into the soil after watering. It will move easily through wet soil and will stop or become harder to push when it hits dry soil.
In heavy clay soils, you may have to pulse-irrigate--watering until puddling occurs, stopping until the water is absorbed into the soil, then repeating--to avoid wasteful runoff. Automatic controllers make this easy.
4. Apply water with care
Irrigate early in the morning, when winds are calm and evaporation is at a minimum, so that water goes into the soil and to plant roots.
Water only the target area. There's no need to sprinkle sidewalks, driveways, or the side of the house.
Apply a layer of mulch (such as ground bark or gravel) to the soil to reduce evaporation. Use a 1- to 2-inch-thick layer around annuals, perennials, and vegetables and a 3-inch-thick layer around trees and shrubs.
5. Maintain your irrigation system
To make sure your system operates efficiently, examine it frequently, checking for leaks, clogs, or misdirected sprinklers or drip-emitters. Sprinklers. Look for signs of trouble. If sprinklers are spraying more water on paving or other unintended areas than on lawns, adjust them. Unclog heads, using a knife or a piece of wire. Water-filled valve boxes or leaking sprinklers may be a sign that valves need to be repaired or replaced. Drip-irrigation system. Check for leaks--geysers, puddles, eroded soil. Secure tubing that has come loose. Replace or clean clogged dripemitters and mini-sprinklers. Clean the filter as needed.
6. Adjust watering schedules with weather
Since plants use more water during hot, dry weather, you need to water more often in summer (and on windy days) than in spring or fall. In many regions, plants don't need any supplemental water in winter..
This irrigation schedule illustrates the maximum weekly water needs of lawns in a Northern California water district.The weekly sprinkler run time (the minutes column) is based on an application rate of 2 inches per hour spread out over a week.
Soil texture and Water penetration
Applied to sand, 1 inch of water Penetrates about 12 inches. Applied to loam, 1 inch of water reaches about 7 inches down. Applied to clay, 1 inch of water soaks only 4 to 5 inches.
Irrigating by zone
By grouping plants with similar water needs, savvy Western gardeners can apply water efficiently, make the best use of low-volume irrigation systems, and be sure that no plants are being over-or underwatered. This illustration shows one way to group various plantings; the lawn can be watered by in-ground sprinklers, fruit trees by a drip-emitter line, vegetable and flower beds by a drip-emitter line, shrubs by individual drip-emitters, ground covers by pop-up sprinklers, and shade trees by a deep-root irrigator, as needed.
A hose is enough to handle your watering if you have just a few outdoor plants or even a small lawn.
Hoses vary in quality. Depending on the manufacturer, they may be made of rubber, vinyl, or a combination. The best hoses incorporate multiple layers of reinforcing fabrics such as nylon or rayon, and they have strong couplings made of brass (the thicker the better) and quality swivels (hexagonal-shaped for easy gripping). Also look or a protective collar just below the coupling, which prevents the hose from kinking at the faucet.
Garden hoses vary in length (25, 50, 75, and 100 feet) and inside diameter (1/2, 5/8, and 3/4 inch). The larger the hose, the greater the volume it delivers. To tailor your hose to various water situations, you can choose from these attachments.
HOSE-END NOZZLES turn hose-flow into a variety of sprays, from strong jet to gentle mist. Some have long handles, making them especially helpful for watering hanging baskets. Many have built-in shut-off valves.
PORTABLE SPRINKLERS (impulse, oscillating, rotating, stationary, or traveling) help you water small lawns. Choose a sprinkler with a pattern that matches the shape of the lawn you need to irrigate.
DEEP-ROOT IRRIGATORS attached to hoses can inject water 18 inches down into tree root zones. (See photo on page 70.)
ON-OFF TIMERS, at their simplest, are designed to fit between a faucet and a hose. You set a dial and the timer turns off the water at the designated time. You can also use an egg timer to remind you to turn off the water. HOSE YS turn one faucet into two or more. On some models, each branch of the Y has a shutoff valve, so you can use them separately; this is handy if you are running several drip-irrigation lines or soaker hoses from one faucet.
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|Date:||Aug 1, 2000|
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