Strategies for summer watering - gardening

Sunset, August, 2000 by Lance Walheim

Six easy steps you can take now to give your garden the amount of water it needs, without waste

* 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.

* Lawn

* For a small lawn, hose-end sprinklers can work well.

* Vegetables

* 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.