Time to water the garden
Plan ahead to avoid stressing plants
After we’ve shivered and sloshed through a cold, wet spring, this may be hard to imagine — but it’s time to think about watering the garden.
“Trees and other plants in the Midwest go through a sort of minidrought every July and August,” said Sharon Yiesla, plant knowledge specialist at The Morton Arboretum in Lisle. “That’s just a couple of months away, so homeowners would be wise to prepare for it now.”
By thinking ahead, you can help your plants avoid water stress that can weaken them and make them more vulnerable to pests and diseases. The mass of a mature tree is roughly 35% water, and a tomato plant is at least 90% water.
“All kinds of plants need sufficient water to stay healthy through the summer,” Yiesla said. By July, they will have long since used up the water added to the soil by the rains of April and May.
Yet if we don’t pay attention, it’s also easy to overwater. “That’s not just wasteful, it’s harmful,” Yiesla said. “Watering too much can distort plants’ growth and lead to some kinds of disease and pest problems.”
For example, overwatered lawns provide a perfect habitat for grubs, many of which hatch into Japanese beetles.
Here are some suggestions from Yiesla for preparing to water this summer.
Turn off the sprinkler system’s automatic timer
“Watering on a set schedule is a recipe for overwatering or underwatering,” Yiesla said. “If the system turns on when there’s already moisture in the soil, it will encourage grubs and root rot. If it turns on briefly two or three times a week, it will barely dampen the soil surface. That will leave the grass and other plants underwatered while still running up the water bill.”
Instead, shut off the timer. Turn on the sprinklers manually to water deeply only when you’ve determined that the soil is actually dry.
Garden according to the real weather, not the calendar
“We need to pay more attention nowadays, because our climate has changed and made the weather more volatile and unpredictable,” she said. “We can’t go by assumptions from 20 or 30 years ago.”
Form a routine of regular checking, not regular watering
Many gardeners have a habit of watering every morning or every Saturday. Instead, make a habit of checking the soil to see whether or not it needs watering. The easy way is to dig down a couple of inches with a trowel, touch the soil to see if it’s moist, and consider the plants that are growing in the spot.
“For lettuce seedlings, you need moisture in the top inch of soil, but for established trees, shrubs, perennials and lawns, it’s sufficient if the soil is moist 2 inches down,” Yiesla said.
Water slowly and deeply, but not too often
Your goal should be to moisten the top 6 inches of soil. Then allow enough time — more time in cool weather, less time in hot weather — for the water to trickle down deeper and the top few inches of soil to dry out. Water again after you’ve checked the soil for moisture.
Try soaker hoses
When these hoses are laid on the soil in garden beds, their tiny perforations allow water to ooze out slowly all along their length. Soaker hoses deliver water right to the soil, where the roots are.
“They reduce the chance of plant diseases because they don’t get the foliage wet,” Yiesla said.
Since the water soaks in so gradually, roots have time to absorb it. Soaker hoses are less wasteful than sprinklers because they don’t fling water through the air to be lost to evaporation. Place the hoses early, then cover them with mulch and leave them in place for the whole season.
Plan for watering new trees and other plants
Because their root systems are immature, trees and shrubs need extra watering for their first two to three years.
You can water them with a soaker hose, a sprinkler, special watering bags that zip around the trunk of a tree or even a bucket.
“Water deeply, right near the base of the trunk where the roots are,” Yiesla said. “As a rough rule of thumb, plan on 10 to 15 gallons each time at intervals of a week or 10 days, depending on the weather.”
Protect all plants with mulch
Among many other benefits, a layer of mulch prevents water from evaporating from the soil. In perennial beds, an even layer 1 or 2 inches deep is enough. Around trees and shrubs, spread mulch evenly in a wide area about 3 to 4 inches deep. “Just be careful not to pile mulch against the trunk,” Yiesla said.