Greener Gardening: Watering in The Summer Heat

By Tricia Bennett

As summer heats up, it’s the ideal time to ensure that you’re using good watering techniques in your garden and landscape. Lack of water causes wilting, reduced growth and plant death. Wilting is a condition in which a plant’s roots are unable to provide adequate moisture to the stems and leaves. Plants can tolerate wilting for short amounts of time, but it can cause permanent damage. Water stress also makes plants and trees more susceptible to disease and insect damage. Too much water can result in root rot, root disease and wilting. It also reduces the amount of soil oxygen that is available for a plant.

When watering, Phipps Outdoor Display Manager Jessica Horenstein recommends prioritizing trees and shrubs as they are the foundation for the home landscape. They take years to establish and grow, so it’s worth the time and effort to promote their health. “Mature trees are priceless,” she says. “With more weather extremes, trees are hit in ways that they simply are not used to.” Horenstein also suggests that gardeners move toward using more resilient plants, which may reduce the need for watering. “We want to be good environmental stewards, and using less water is a part of that,” she says.

Check the Phipps list of Top 10 Sustainable Plants for options that require minimal watering and fertilization once they are established. For tips on “Creating a Water-Wise Landscape”, read more from the Virgina Cooperative Extension.

As a general rule, Penn State Extension says one inch of water per week, including rainfall, is sufficient for plants that are in the ground. Experts suggest using a rain gauge to monitor your yard and to help determine whether you need additional water. Weather conditions vary widely throughout Western Pennsylvania, so an accurate measurement for your yard is essential. Read more on PSU's advice on how to beat the summer heat. Water in the morning because air temperatures are lower. Avoid watering in the middle of the day, as water will evaporate before it can be absorbed by plants. “Early morning with a thorough soaking is the way to go,” says Horenstein. Water deeply at the roots. Soaking leaves, especially in the evening, can lead to fungal issues. Water thoroughly but allow the soil to become fairly dry before the next watering.

Horenstein says new plantings will initially require more water than established plants, trees and shrubs. New plantings lack extensive root systems and are especially at risk for drying out during heat waves. After a one- to two-year period of targeted watering, many plants, especially natives, will not need additional watering unless there is a drought.

Some gardeners might want to consider drip irrigation. Horenstein said it’s ideal because it puts water close to the soil and is easy to adjust as weather conditions change. Penn State Extension has some options on watering for watering home gardens and landscapes. For more information on installing irrigation systems, you can consult a Phipps Sustainable Landcare Accredited Professional.

Using containers gives gardeners more options and flexibility, but Horenstein said they must remember that containers dry out faster than beds. She suggests checking the soil with your fingers, and says some containers might need to be checked twice a day. If a plant is dry, water might just run through the container without being absorbed by the soil. “You can do a ‘pre-water’ first,” she says. “Get some water in there and recheck the pot in 15-20 minutes.” Continue to water until drainage comes out of holes in the bottom of the container. Learn more about the dos and don’ts of watering from Penn State Extension.