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Drought-Proofing Your Garden—Essential Water-Saving Strategies
Plants & Gardens News Volume 17, Number 2 | Summer 2002
by Janet Marinelli and Niall Dunne
Severe to extreme drought conditions are affecting large portions of North America, including the Atlantic Coast from Maine to Georgia, the Plains states, and significant parts of the Southwest as well. New York City's experience has been typical of many urban and suburban areas. On April 1, the city declared a Stage 1 Drought Emergency, introducing numerous restrictions on industrial, municipal, and domestic water use. Gotham's gardeners are only allowed to water their lawns every other day for two hours in the morning and the evening, and they can only water the rest of their plants using hand-held watering cans or low-flow irrigation equipment.
Don't be fooled by those days of plentiful rain in April and May, because water reservoirs in much of the East are still well below normal capacity. And there has been no easing of water restrictions. We still need an abnormally high amount of rainfall for water supplies to get back on track by next year.
A drought emergency is a time to take steps to substantially reduce water use in the garden. It's also a good time to take stock of our gardening practices and to consider how out of tune they are with normal fluctuations in yearly rainfall and snowfall. Below are some tips on how to conserve water while coaxing your plants through the current drought. These are followed by longer-term solutions that will help make your garden more compatible with natural precipitation patterns.
Drought Facts
First, a couple of basic questions: What's causing the current drought? With icebergs the size of Rhode Island breaking off Antarctica, one might be tempted to link the drought to human-influenced global warming. But experts say it's premature to characterize what is probably a normal fluctuation in the weather (the short-term state of the atmosphere) as a climatological event (a long-term trend).
The earth's climate, of course, continuously changes without any help from us, cycling through periods of warming and cooling. It has to do with everything from fluctuations in solar activity to shifts in the planet's orbital tilt. In other words, even if you left humanity out of the picture, drought would be a regular occurrence.
What exactly is a drought? Climatologists have a list of different definitions, reflecting the complexity of the phenomenon. Generally speaking, it is a period of less-than-average rainfall. Predicting when a drought will end, or when a new one will begin, is close to impossible.
"Basically each day is a new slate," says Mark Svoboda, a climatologist with the National Drought Mitigation Center, an advisory institution based at the University of Nebraska-Lincoln. "The drought could be over soon, or it could draw out for years."
Svoboda points out that "because drought is so unpredictable and hard to read, and because it is a natural part of our climate cycle, we need to be conserving water at all times, even when it seems to be in abundance."
Ten Short-Term Tips
Here are ten easy ways you can conserve water in your garden this summer without harming your plants:
Water your plants early in the morning. Mornings are cool, and water doesn't evaporate as readily as it does in the heat of the afternoon. Evenings are cool too, but water sitting on leaves overnight can cause fungal diseases.
Water less frequently but deeply. Frequent, shallow waterings lead to weak, shallow-rooted plants. Less frequent, thorough waterings encourage roots to grow deep, where the soil stays moist longer.
Water the soil, not the plants. Use a watering can, soaker hoses, drip irrigation, or other water-conserving irrigation techniques that saturate the soil while leaving the foliage dry.
Mulch your plantings. A two- to three-inch layer of organic mulch such as shredded leaves or bark or compost slows evaporation by shading the soil, slows water runoff, and as a bonus, enriches the soil as it breaks down.
Don't prune, fertilize, or apply pesticides during a drought emergency. All of these would put additional stress on your plants.
Put off major planting projects until water is more plentiful. All newly established plants require a lot of irrigation. It's best to delay planting trees, shrubs, and large herbaceous borders until the drought is over.
Choose drought-tolerant plants for pots and for filling in existing plantings. Certain characteristics indicate that a plant has low water requirements: Plants with silvery, hairy, or fuzzy leaves (such as woolly thyme, Thymus pseudolanuginosus), succulent leaves (such as rose moss, Portulaca species), or leaves with a waxy coating (such as ivy-leaved geranium, Pelargonium peltatum) are good choices. Plants with long taproots, such as butterfly weed (Asclepias tuberosa), are good choices as well. See "Drought-Tolerant Plants," page 13, for more recommendations.
Improve potting mixes. For your container plants, consider incorporating hydrogels into the potting soil. These water-retaining polymers hold several hundred times their weight in water and release it gradually to the plants' roots. Be careful not to add more than the recommended amount—too much of a good thing and your plants will be pushed out of their containers by the expanding crystals. Presoaking hydrogels until they are fully expanded makes them easier to incorporate with the potting soil in the proper ratio.
Cut down on mowing, fertilizing, and watering, and let your lawn go dormant. Mowing causes water loss. Mow during the coolest part of the day, and leave the clippings, which return small but valuable amounts of moisture to your lawn. Raise the mowing height, because taller grass shades the soil, reducing water loss; the University of Massachusetts Extension recommends settings of two to three inches. Most turfgrasses are adapted to summer drought. They turn a nice buff brown color as they go dormant, sending their water reserves down to the roots for safekeeping. Given a bare minimum of water, your lawn will green up again in fall when temperatures cool.
Consider collecting and recycling water. Depending on where you live, you may be able to connect your downspouts to rain barrels to collect roof runoff. When water used for boiling pasta and vegetables cools, use it to water your plants. Use of other types of "gray water," such as that from showers, baths, washing machines, and dishwashers, is regulated by some municipalities, and the detergents and other chemicals in the water can be harmful to some plants.
Long-Term Solutions
The following additional steps will make your garden much less vulnerable to future droughts as they preserve supplies of fresh water. It's best to save these projects until the current drought is over.
Reduce the size of your lawn. The typical lawn requires regular irrigation and care to maintain its aesthetic appeal. Consider widening your borders and planting beds, and replacing thirsty turfgrass with water-thrifty trees and shrubs. Once established, most trees and shrubs require less water than herbaceous plants. Fill in with drought-tolerant perennials, annuals, bulbs, and groundcovers. See the box below for specific recommendations.
Add organic matter to the soil as you plant. Compost and other organic matter increase the soil's ability to retain moisure.
Switch to low-maintenance grasses in remaining lawn areas. One very attractive alternative is buffalograss (Buchloe dactyloides), a fine-leafed, soft-textured species indigenous to the Great Plains. Because it is adapted to the periodic and prolonged droughts characteristic of that region, it needs minimal water once established and no fertilizer. For profiles of this and other water-efficient grasses, see BBG's handbook Easy Lawns.
Supplier Information
Most good local home-improvement stores and garden centers carry a range of products that can help you conserve water. Another retail source is the Gardener's Supply Company (128 Intervale Road, Burlington, VT 05401; 800-427-3363; www.gardeners.com), which sells soaker hoses, drip-irrigation systems, root-zone watering devices, rain barrels, water-efficient planters, and hydrogel. M.K. Rittenhouse & Sons (1402 Fourth Avenue, St. Catherines, ON L2R6PQ, Canada; 877-488-1914; www.rittenhouse.ca) offers many of the same products plus a rain-sensitive sprinkler system. Home Harvest Garden Supply, Inc. (3807 Bank Street, Baltimore, MD 21224; 800-348-4769; www.homeharvest.com) is an online company that sells drip-irrigation systems, watering cans, and precision hose nozzles. Agrosoke International (1004 N. Bowen, Arlington, TX 76012; 800-880-2476; www.agrosoke.net) manufactures the hydrogel Agrosoke™.
For more drought information, visit BBG's Gardener's Resource Center or the Drought Response section of our web site.
Brooklyn Botanic Garden Director of Publishing Janet Marinelli is editor of BBG's renowned series of quarterly gardening handbooks and the author of Your Natural Home and The Naturally Elegant Home. Janet is a champion of the gardener's role in the preservation of the planet, a philosophy that informs her P&G News column, "Down to Earth." It's a philosophy that also serves as the bedrock for her latest book, Stalking the Wild Amaranth: Gardening in the Age of Extinction. In Stalking the Wild Amaranth, Janet tells of her quest for a landscape art that protects disappearing species, both flora and fauna. It's a gardening journey marked by humor—ecologically sensitive gardening needn't be a dreary affair, Janet insists. "We can do our part," she says, "and still have flair and fun."
Niall Dunne is associate editior of Plants & Gardens News.