The moist start to summer lulled us into thinking there would be rainfall all season long. Then it stopped, and rain in this region was 32 percent below average for August. During the first three weeks of September, it rained once -- precipitation that measured just one hundredth of an inch at Reagan National Airport.
All of a sudden, we're in drought conditions, which is tough to believe in light of the tremendous amount of moisture the South and the North have received. So, let's not become complacent about following proper water-conservation measures.
Your site conditions will dictate how often attention is necessary. The intervals between watering can change depending on soil type, exposure to sun and temperature. Use common sense to determine the point at which plants need more water. Feel the texture of the soil. Sand requires more water than clay. Soil dries faster in sun than shade, and cool weather greatly reduces water loss.
Scratch a little soil with a cultivator and monitor the moisture. Mud is easy to detect. It will pack together or be sticky. Properly moist soil appears darker, crumbles, and feels cool and wet. Weeds are easy to pull. If soil crumbles and powders, it should be watered.
Newly installed plants need extra monitoring. Soil around them could be moist, but the medium around plant roots could be dry. Check moisture at the root ball.
Take as little water from your public works as possible. Here are some suggestions for collecting water and irrigating with it:
* Collect the water coming from your air conditioner. Condensers are putting out a steady flow of moisture. Most of that water is draining away. Pipe it directly into your garden or collect it in a receptacle and pour it where it's most needed. Use rainwater the same way, if we get any.
* You can collect a gallon or more a day from a dehumidifier.
* To irrigate, always water slowly, almost dripping it into the soil.
* Keep the water source close to the ground.
* If possible, use a soaker hose or drip line and lay the water into the soil just below ground level.
* Early morning watering is the best, but irrigation in the evening has the least amount of evaporation.
* Irrigate with "gray water," or water that would ordinarily be drained away, such as bath, dish and vegetable-cooking water. Pour around the roots of your parched plants. Do not use water that contains bleach, automatic dishwashing detergent or fabric softener.
* Bathe instead of showering, and use the bath water on plants, to wash cars or in other innovative ways.
* Gray water is safe to use on fruits and vegetables. Do not wet the foliage of the plants when watering; soak only the ground around the base.
* To hold moisture, use mulch. You can use dried grass trimmings, not fresh ones. Lay compost over your beds, and when you water, it will be working organic material into the soil at the same time.
* Check for soil moisture at varying depths to make sure you've gotten to the base of the roots of the plants without watering too deeply. You can stick your finger into the soil and feel for wetness. Or, use a screwdriver or quarter-inch-diameter wooden dowel to poke into the soil, and check it for moisture.
* Don't water during hot, windy or rainy weather.
* Repeat watering is especially important on sloped sites and areas where soil percolates quickly. To test your soil for percolation, dig a hole, and before putting in organic material or plants, fill with water and see how fast it drains. It should run out slowly. If it drains quickly, you will need to irrigate the site often.
* Use a rain gauge to keep track of how much natural precipitation your landscape has received. Then you'll have a better idea of when you need to water or not without checking the soil.
* Avoid using a sprinkler that throws a fine mist into the air. You want droplets to drench the soil. A mist into the air loses too much water to evaporation.
* Keep ahead of weeds. Weeds use moisture; getting rid of them helps keep down the competition for moisture.
* Move container plants to sheltered areas, away from excess wind and sun.
* Use one-gallon plastic milk jugs with screw-on caps for a drip system. Using a wood awl, carefully make a 1/16 -inch-diameter hole in the bottom of the jugs, just off center. Fill jugs with water and place them next to plants. They will saturate the root zone without runoff. When the weather is dry, loosen the caps. When there is good soil moisture, keep the caps snug. With this system, plus compost, there is little evaporation.
* A commercial watering product called the Treegator has been valuable for slowly watering trees. It's a green, fabric-reinforced plastic bag that zips around newly planted trees and holds 14 to 20 gallons of water. There are two small holes that drip water slowly. It percolates into the soil over six to 10 hours, and all of the water stays in the immediate vicinity of the tree's roots. Treegator is available in many garden centers. For more information, go to www.treegator.com or call 800-800-7391.
The most stressed plants I've seen this week are the flowering woodland shrubs of the heath family because they felt the rain shortage first. These flowering broadleaf shrubs, many of them evergreen, are the sweethearts of the woods in our region and include azaleas, rhododendrons, Japanese pieris and mountain laurels. They have shallow root systems. However, you will see wilting and yellow leaves on almost all of your ornamental and woodland plants now.
When water is this scarce, the plants I worry about least are annual flowers and turf grass. The main impact of annuals is aesthetic; if you lose them to drought, you lose them for only one year. As for grass, you need a great amount of overhead water to keep a lawn green, which means you should use sprinklers rather than drip irrigation -- and sprinkling is an inefficient way of using water. But healthy turf can often renew itself from its roots, even after six to eight months without rain. Trees won't.
Even if some woody plants will grow leaves again in spring, the choice between replanting trees and shrubs versus seeding grass is an easy one. You can't sprinkle seeds and get a forest in one or two growing seasons. But seed and the addition of water can grow grass in a matter of days and give you your lawn back in a season or two.
Lawns are best watered from above. There are varying theories on the intervals. Some schools of thought call for a quarter- to half-inch every other day for lawns in summer. Other, more common guidelines are one inch on the surface once a week; however, it depends on the site you are irrigating.
Joel M. Lerner is president of Environmental Design in Capitol View Park, Md. E-mail or contact him through his Web site, www.gardenlerner.com.