SMartGarden™ - Water Conservation

Watering wisely saves time and natural resources

Given the droughts and higher average temperatures many parts of North America have been experiencing in recent years, water consumption in the garden is a growing concern. By combining conservation and efficiency, both the amount of water used and the time spent delivering it to the garden can be minimized.

Plant selection and placement

While all plants need water to thrive, some need less than others. For instance, succulent plants store water in their fleshy leaves for use when needed and the foliage of plants such as lamb's-ears (Stachys spp.) and wormwoods (Artemisia spp.) are covered with fine white hairs that shade the leaf surface and reduce moisture loss. Many ornamental grasses and prairie natives have deep roots that range far to seek water. Once established in the garden, these and other drought-tolerant plants minimize the need for supplemental watering.

But most gardeners don't want to limit their plant selection to drought-tolerant species. To make watering more efficient, however, group thirsty plants together-ideally close to a water source. By designing your garden with plants' water requirements in mind, it will be easier to develop watering systems tailored to the needs of different sections of the garden.

Supplementing Nature

Water requirements are affected not only by the type of plant, but by a number of environmental variables such as temperature, wind, sunlight, and season. Soils also vary in their capacity to retain water. Thus there is no fixed rule for how often you will need to water; observing your plants and checking your soil regularly will provide the best clues.

All plants should be watered when they are first set out, and regular watering should continue until their roots are well established. When watering plants, be sure to water thoroughly to encourage deep root development. Plants with extensive and deep root systems can obtain more water from the soil and are less subject to injury from temperature or moisture fluctuations.

Early morning or evening-before or after the heat of the day-are the best times to water because less will be lost to evaporation. Because wet leaves are more prone to disease, try to water at the base of plants.

Watering Systems

Hand watering, using a watering can or a hose with a water breaker, allows you to get "up close and personal" with your plants, but this system requires a great deal of time and is impractical for large gardens.

One of the most efficient watering systems is drip or trickle irrigation. It takes effort to set up initially, but in the long run it saves time and reduces water use. It can be designed to accommodate any garden size or style and can also be used for container plants. Water is delivered directly where needed through emitters at the end of water tubes. Little water is lost to evaporation or wasted on areas between plants. The spacing of emitters and rate of flow can be adjusted. If the water in your area is hard, however, the narrow tubes can quickly become clogged with minerals. If a tube is clogged, or becomes displaced, plants can suffer before the problem is noticed.

A soaker hose allows water to seep slowly into the soil along the length of the hose. Soakers are similar to drip systems but are easier to move from place to place. They are particularly useful in vegetable gardens, where they can be stretched along the rows.

For permanent plantings, an underground, automated sprinkler system can be installed, preferably before the garden is planted. These systems must be carefully maintained, and plants must not be allowed to grow over the nozzles to block or divert the spray. These systems can be programmed to run on a timer.

Portable sprinkler systems are relatively inexpensive and versatile but rarely deliver a uniform spray. Hoses connect the water source with a variety of sprinkler attachments-fans, oscillators, pulsating heads. A significant amount of water from sprinklers is lost to evaporation, and use of overhead sprinklers may lead to an increase in foliar disease problems.

Recycling Nature

A rain barrel that collects water from the roof saves water that would otherwise be lost as runoff. Several manufacturers produce plastic barrels with fittings to connect the downspout with the barrel, and a spigot so you can access the water. The barrels can be attached to drip irrigation systems or simply used to fill your watering can.

Mulching

Mulching around plants conserves moisture in a number of ways. By physically covering the soil, less moisture is lost to surface evaporation. Mulches inhibit the growth of weeds that compete with your desired plants for water. And mulches help prevent soil crusting-the formation of a dry surface layer that impedes water penetration into the soil.

Rita Pelczar, Associate Editor