Cool it down in the garden

By Kym Pokorny

The forecast promises high temperatures this summer, so take care to protect plants for the long, hot haul.

“Already this year, I’ve noticed soils are drying out more and sooner than I’ve seen since I moved to Portland eight years ago,” said Weston Miller, a horticulturist with Oregon State University’s Extension Service. “It’s critical to be proactive about watering.”

Once soils dry out, plants get stressed and struggle to recover, he explained. So water deeply and regularly. Especially vulnerable are plants put in this year, but all need attention.

“Get water down to where the roots are,” Miller said. “After watering, dig a small hole to see how far the water has penetrated.”

Irrigate for 45 minutes and then measure. For trees and shrubs, look for water to penetrate the soil to at least eight to 10 inches. For perennials, annuals and vegetables, shoot for moisture to reach 6-8 inches depth.

Soaker hoses or drip systems are best for irrigating because they are more efficient at delivering water and cut down on evaporation, Miller said. As a last resort, use an overhead sprinkler to cover a lot of space. If possible, don’t water in the middle of the day as it will speed up evaporation and can burn foliage on particularly hot days.

While you’re out taking care of your plants, he said, don’t forget to take care of yourself, too. Avoid working in the garden during the hottest part of the day, wear a hat, drink plenty of liquids and use sunscreen.

Miller offers these tips to take care of the garden in hot weather

* Check irrigation systems, including soaker hoses and drip systems, for leaks so water doesn’t flood one area and miss another.

* Planting in summer isn’t recommended. However, if it’s necessary, use the “mudding in” technique. Dig a planting hole, fill with water and let it sink in. Fill with water again and put in the plant while there’s still water in the hole. Add soil and water again.

* Put mulch around plants to slow down evaporation and keep soil cool.

* Move potted plants and hanging baskets into the shade and check often for dryness. They may need to be watered at least twice a day.

* Use shade netting (available at garden centers) to protect plants on especially hot days, especially newly planted vegetables and annuals. In a pinch, use old sheets or curtains.  You’ll want to prop netting or cloth on PVC pipe, stakes or heavy-gauge wire molded over plants.

Set lawn mowers to cut at a 3-inch height, which will encourage roots to grow deeper and have access to more water. To keep lawn green, water at least an inch a week. Use a tuna can or rain gauge to measure how much water is applied. In the Portland area, you can check your weekly watering number at the Regional Water Providers Consortium website. The number will tell you how many inches of water to give lawn in the current week.

Observe plants in full sun to see how they perform through the summer. Some may need to be relocated to a site with some afternoon shade.

In the future, when choosing a plant consider drought-tolerant selections and natives. For suggestions, refer to Extension’s guides Gardening with Oregon Native Plants West of the Cascades and Selecting Native Plants for Home Landscapes in Central Oregon.

Photo by Lynn Ketchum. Water plants deeply and regularly to keep them at their best through the hot summer months.