University of Illinois Extension

2013: Another Dry Gardening Season?

Gardeners were really glad to see the cooler weather and some rainfall at the end of the 2012 gardening season. The question is whether or not 2013 will be any better, said a University of Illinois Extension horticulture educator.

“For a lot of areas in Illinois, the usual fall rain did not materialize and through mid-January snow has been scarce,” said Richard Hentschel. “In a more normal year, plants start the season off by using the soil moisture available from the melted snow and spring rains. Later those plants will rely on the soil moisture farther down in the soil profile. This is why after a landscape plant is established gardeners tend not to worry about watering.

“As we approach spring not only is the deep soil moisture lacking, but any upper soil profile moisture available will be quickly used unless there is adequate rainfall. If this weather pattern continues, it will mean another gardening season requiring lots of water and close attention to the condition of all landscape plants.”

Gardeners can do some things out in the yard that are beneficial to our landscape even if we do get adequate snow and rain from late winter through spring.

“If you have a compost bin or pile adding organic matter does more than just feeding your plants,” he said. “Organic matter can hold soil moisture for later use by the plants. How important is organic matter? A garden soil that contains 1% organic matter holds 1/3 gallon of plant available water per cubic foot. A soil that contains 3% organic matter will provide 1 gallon of available water.

“Composts can be incorporated easily into an annual bed of flowers or vegetables, either in the fall or early spring before you plant. In perennial beds adding composts between plants and letting it decompose working itself into the soil profile is the way to go. On more permanent landscape plantings, the composts can be applied as if it was a mulch layer much like using bark mulch. Just like the bark mulches the composts will break down and again finds its way into the soil profile.”

The third advantage that composts provide is the beneficial change in soil structure. This change allows root systems to grow deeper into the soil, finding more soil moisture as they do. When you combine the availability of nutrients, the water holding capacity of organic matter and the change in soil structure, it is easy to see how this will help plants, drought or not.

“Plant selection will also be an important part of redoing a planting or bed that lost plants from the drought, disease or insects,” he said. “If there is a location that has historically been dry in your landscape, plants that have a strong drought tolerance will perform much better than a high water use plant. Dry sites typically have a western or southern exposure or those parts of the yard that are on a slope or in soils having a high percentage of sand. Sand is just a very small rock and does not have any nutrient or water holding capacity and promotes very rapid drainage after a rain”

Many of our native plants have root systems that can take advantage of soil moisture several feet into the soil profile. Our lawn grasses have roots that in a good soil go down eight to ten inches, native grasses will have roots 6 feet or more into the soil.

“How we water will likely be different in 2013,” Hentschel said. “Watering restrictions are almost certain and for many gardeners something that has been in place already for a number of years. By respecting those restrictions, a ban on watering all together can be avoided or at least postponed.

“Water properly as to not waste water, placing it to the best advantage of the plants is preferred. Watering at the base of a plant or using drip hose rather than using a sprinkler prevents water loss into the air or off target areas. Allowing the water time to soak in deeply will encourage plants to send roots deeper into to the soil, making them more drought-tolerant. This may mean watering once, letting it soak in and coming back a second time to thoroughly moisten the soil.”

If you have watering restrictions to even or odd days does not mean you have to water on your appointed day if the soil is moist enough, he added. Frequent shallow watering will not promote the root system you want your plants to have.

“Always water deeply when you do water and then wait until soil begins to dry out before watering again,” he said. “Do not use the plants as an indicator and wait until you see wilting.”