The drought-proof garden

Local rain gauges suggest homeowners need strategies to help their gardens get through the dry months ahead.

In The Garden

April 26, 2002|By Marianne Auerweck | Marianne Auerweck,SPECIAL TO THE SUN

Don't let the early spring rains fool you. Maryland is still firmly in the grip of a severe drought.

With watering restrictions already imposed in parts of the state, and even stricter measures almost certain to follow, gardeners are facing some tough decisions as the season gears up.

"We've started to get some rain, but we still have a very serious problem, and the hottest, driest part of the year is yet to come," said Rich McIntyre, spokesman for the Maryland Department of the Environment.

But even under drought conditions, there are ways to create bountiful gardens and still conserve water. We've set out to guide you toward a successful gardening year, offering advice on how to improve your odds in spite of nature's shortcomings.

An inch of rain every week surely is at the top of every gardener's most-wanted list.

It isn't likely to happen, but even if it does, drought conditions will remain, and mandatory limits on outdoor water use will force gardeners to search for ways to satisfy their urge to plant while still conserving precious water.

Gardeners who have put years of time and thousands of dollars into their landscapes can't bear to give up and let nature take its course. And no one likes the idea of carrying bucketfuls of water to parched plants.

Fortunately, there are ways to take advantage of whatever rainwater comes our way, and experts agree that it begins with soil preparation. Neither sand nor clay is capable of providing moisture and nutrients to sustain a healthy, diverse garden.

Clay soil generally lies wet through the winter, then dries rock-hard, unable to absorb and retain water in the heat of summer. Good root development is impossible. Sandy soil drains too quickly and is unable to hold nutrients.

The cure for poor soil - sand or clay - comes from the addition of organic material, such as compost, manures and humus. The goal is to create soil that will retain water long enough for plants to absorb it without being waterlogged.

Organically enriched garden soil helps plants develop deeper root systems and absorb nutrients and water more efficiently. Many municipalities stockpile composted leaves at landfills, and it is available free or for minimal cost to residents. For small gardens, bagged humus can be purchased from any garden supply center, and for large jobs you can buy bulk compost from almost any landscaping company.

Working water-absorbing polymers into your soil also will improve its ability to hold onto water. These products, sold under brand names like Soil Moist, TerraSorb, Broadleaf P4, and Hydrosource, are available through several garden supply catalogs and some retailers. When dry, they resemble coarse salt crystals, but they will absorb 200 times their weight in water, swelling into gelatinous globs that gradually release their moisture as the soil around them dries. Polymers remain effective for up to 10 years, gradually breaking down into carbon dioxide, water and ammonia.

One pound of polymer crystals costs less than $20 and will treat 100 square feet of soil, or about 100 plants. They also are useful in container gardens, hanging baskets and window boxes.

Though many landscapers have used polymers for several years to help protect new plantings, they have only recently caught on among home gardeners.

A 3-inch-deep layer of mulch, a top-dressing of compost or a combination of both also will help soil hold moisture.

"The single best thing a gardener can do to preserve moisture is to mulch well," said Jane Callaghan of the Growing Collection, a landscape design firm in Lutherville. "You can amend the soil all you want, but if you don't preserve the moisture, plants are going to die."

Callaghan recommends using shredded hardwood mulch instead of bark nuggets.

"Shredded mulch is denser, and it compacts better," she said. "Nuggets allow more evaporation, so it's less effective."

Besides amending the soil, gardeners can conserve by capturing rain water for their plants. The state Department of Natural Resources reports a marked increase in inquiries about rain barrels.

Though any large receptacle will do, Marylanders must be careful not to provide breeding grounds for mosquitoes. If you collect rainwater in an open-topped container, float mosquito dunks on the surface. They contain Bt, a bacteria that kills developing mosquito larvae.

During a prolonged drought, trees and large shrubs are particularly vulnerable to disease and pests. Any amount of rain will benefit garden plants, but as the water table drops, tree roots are unable to find the moisture they need - as much as 40 gallons a day for a large tree.

"People need to be alert to signs of disease and pest problems on trees, especially this year," said Lawrence Leaf, of Leaf Nursery in Baltimore. "We had a warm winter, and some types of larvae didn't die off as they normally would."

You can provide extra water to trees by attaching flexible drain pipe to downspouts and directing extra rainwater to trees or shrubs.

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