The Scoop: Heatwave Gardening

Published 3:15 pm Friday, June 28, 2024

By Susan Jonas

Garden Club of Danville


Hot enough for you? Gardening in the middle of a heatwave is bad enough, without the added pressure of a long dry spell. The only plant thriving in my garden is crabgrass.

This seems to be a new pattern for Kentucky weather, with milder winters, wet springs, and hotter, dryer summers. As the climate changes, some plants will adapt or shift their range. Others will eventually fade away without special care. Gardeners will have to adapt, too.

My preference has always been for plants, mostly natives, that can take care of themselves without coddling. I’m not inclined to fight nature. Tough it out on your own buddy, or you’re history.

Since I don’t want an arid garden with gravel, cactus plants, and succulents, supplemental watering looks to be in my future. Besides, those heat and drought loving plants would not appreciate our wet springs, although they can be useful in pots baking on a paved patio.

Your first defense against this kind of weather is good soil with plenty of organic matter to hold moisture and loose enough for roots to go deep. A layer of mulch protects the soil from hot sun while discouraging weeds.

Your garden’s moisture level is something you need to focus on if you want to garden successfully. Knowing how and when to water your plants for optimal efficiency can keep them happy even in the most insufferable conditions.  An inexpensive moisture meter ordered online tells me when to water. Its eight-inch spike works equally well in containers or in the ground, registering dry, moist, or wet.

Another easy trick is to find a plant that serves as a warning sign that your garden is thirsty. In any garden there will be a few plants that suffer from the moisture-zapping heat of summer more than others. Keep an eye on which plants seem to wilt first.  In my garden it’s the wild ginger and brunnera, or forget-me-not. If you find a plant that shows signs of summer fatigue before others, use that plant or plant group as a visual reminder to break out the watering can or hose and make it rain.

Most gardeners know that the best times to water your garden and lawn are early in the morning and once the sun has gone down in the evening. It is not true that watering in hot sunshine will cause the water droplets to scorch your plants’ leaves. Watering during the middle of the day just wastes water to evaporation.

Short of an irrigation system, the best watering method I have found is soaker hoses winding through the beds under a thin layer of mulch. Laid down in early spring, they are simply connected to a faucet when needed.

These porous hoses seep water slowly, getting down to the roots without wasting a drop. The moisture gauge or a finger stuck in the dirt will tell you when it’s wet enough, usually 30 minutes to an hour. You can even install a timer on the faucet to turn the water on and off automatically on a schedule. Just don’t forget about it overnight like I did recently.

Overwatering can lead to problems, including root rot, and fungal infections. You can minimize wet leaves by watering your plants close to ground level instead of raining down on them from above. When watering, soak the ground around your plants, aiming for the roots.

In the heat it’s important to water deeply. If you are using a hose set to shower, give each plant a good 20-30 second drink before moving on. Watering the lawn by strolling across it with the hose nozzle pointed down won’t cut it.

Remember that plants in containers will need to be watered more frequently, as the soil tends to dry out much quicker than the soil in your garden beds.

During a heat wave, you should postpone any fertilization. When the weather gets too hot, plants go into a kind of survival mode similar to dormancy. They won’t be able to absorb and consume the nutrients in fertilizer if the weather is too hot.

All this heat is tough on the gardener, too, so do your outdoor work in the cooler morning and evening hours. Take a hint from your plants and go into dormancy during the hottest hours of the day.