Water Plants During Hot Summer
A guide to watering in extreme heat
Hot, dry summers are rough on plants, especially on non-native plants and those weak from improper care. Don't wait until the soil is bone-dry and cracked. Find ways to continuously give your plants the water they need to stay healthy. Consistent watering helps plants deal with the stress of high temperatures when there's no rain. It's most efficient to water early in the day. This summer's relentless heat has posed challenges to gardeners and their plants. Everything dries out faster when it's hot: flowers and vegetables, whether in a garden or in containers, young trees and shrubs, and lawns from small urban yards to large suburban spreads.
Repeated wilting and re-hydrating is detrimental to most plants, so one of the biggest challenges is trying to maintain a relatively steady supply of moisture to the soil. This is not just to keep plants looking their best (though it does that) but also to promote continued healthy growth and help plants cope with the stress of summer diseases and insects.
Water your vegetables two to three times a week during really hot weather. Watering the garden deeply is critical. The water must go down, down, down to encourage deep roots and get away from the hot soil surface. Put a little cup or can in the garden soil and don’t stop watering until it has collected at least an inch of water from the sprinkler that you set up. (If your veggies are in containers, they’ll probably need water every day or so during the heat because containers tend to dry out faster than the ground.) If you aren’t using a sprinkler, put the cup under your drip or soaker hose. It won’t be quite as accurate, but it’s better than nothing. To hand-water a small plot, or pots, use a nozzle turned to the “shower” setting for gentle, rain-like watering. If water puddles on the surface at first, move on, but come back several times to be sure the water is soaking in and the soil is thoroughly moist.
Avoid wetting plant leaves when you can. Of course, if you use a sprinkler, it is impossible not to wet the leaves when watering the garden, so in that case, water early in the morning so that the foliage will dry early and quickly to minimize disease risk. You can put the sprinkler on a timer so that it comes on just before daybreak, when the leaves may already be wet with dew. The gardening principle here is to avoid adding to the length of time that the leaves stay wet because many diseases need moisture to thrive.
Mulch, Mulch, Mulch! Do what you can to keep water in the ground. An organic mulch such as wheat straw, finely ground bark, pine needles, or chopped-up leaves spread on the ground around and under plants is a welcome barrier between the moist soil and the hot sun. Mulch becomes an insultation against summer heat and reduces soil moisture evaporation. A 2- to 3-inch layer of mulch makes a huge difference in hot weather, acting as a shade cloth to hold in moisture and cool plant roots. Without mulch, the intense sun bakes the soil — and you end up watering the garden even more.
While some herbs (marjoram, oregano and rosemary, for instance) thrive and develop their most intense flavor when grown under hot, dry conditions, many vegetables are negatively affected by heat coupled with wide moisture swings. Cucumbers may be misshapen and bitter-tasting. Potatoes may be knobby, and can develop green areas that are mildly toxic when sunlight penetrates through the cracks of hard, dry soil. (Peel off those green areas before you cook the potatoes.)
Tomatoes frequently develop blossom end rot, a dark, leathery splotch that begins where the flower was attached, and enlarges as the fruit grows. (You can slice off that part of the tomato and use the rest, but you'll lose a sizable chunk of each fruit, and you'll need to use it right away.) The dark area is caused by a lack of calcium available to the developing fruit, primarily from an interruption in moisture uptake.
Plant location is very important. Shaded locations cut summer stress for heat- and sunlight-sensitive plants. Eastern exposures or open areas are generally preferred for blooming plants. Southern or western exposures are subject to direct, intense sunlight, as well as reflected heat. Because walled areas of these hot exposures build up and hold additional heat, only very heat tolerant plants can survive in these locations. Also, consider draft and wind exposure when positioning plants whose foliage may be particularly subject to burn by hot, drying air movement.
How long and how often to water depends upon how long the soil retains moisture and how fast that moisture is being used. A proper balance of moisture and air in the soil is necessary for roots to breathe and do their job. Irrigate to maintain favorable, not abundant soil moisture. Water long enough during each irrigation to allow moisture to penetrate completely through the plant rooting area, but no more often than necessary to prevent foliage wilt! Following this rule, and you'll automatically adjust to the age and type of plant as well as to the differences in seasonal requirements. Deep, penetrating irrigations
each time also keep soil salts washed downward out of the root area.
A drip irrigation system is THE MOST effective, efficient method of watering.
Fertilizing during hot weather should be done with caution!
*Warm-weather gardening tips for all gardeners. Get out and garden as early in the day as possible. Wear light-colored, loose-fitting clothes. Apply sunscreen 15 minutes before going outdoors. Stay hydrated by taking frequent water breaks. Tackle the "must do" chores, like watering, first. Call it a day before you're too uncomfortable. Most gardening chores will wait for you.
