Beat the Heat Gardening by the Yard : Episode GBY-1303 -- More Projects »
Gardening in extreme heat is no fun, and yet even when the mercury soars, there are still chores to be done. Here, master gardener Paul James offers a few tips to help you minimize your time outdoors, so you can maximize your time indoors:
- Stop fertilizing. Extreme heat brings on a form of dormancy in plants--growth and metabolic processes slow. In fact, when it's really hot, some plants will actually begin dropping their leaves or wilting to slow their growth rates even more.
"Fertilizer causes an increase in growth rates, which is fine throughout much of the growing season, but downright crazy when it's really hot," James says. The exception to this rule is container plants, because each watering flushes nutrients out of the potting mix--nutrients that must be replaced periodically. "Of course," he continues. "I'm partial to all-natural fertilizers--compost tea, fish emulsion, liquid seaweed and the like--which I apply to my container plants every two weeks or so." - Resist the temptation to overwater. "It may seem logical that during periods of extreme heat you should water more and more often--and to some extent that's true--but many people actually wind up overwatering their landscape plants, and that can cause big problems."
Overwatering leads to waterlogged soils, and most landscape plants can't exchange oxygen when their roots are in standing water. As a result, they drown. So it's best to stick with your regular watering routine, although you might increase the frequency. In other words, instead of watering every five or six days, you might water every four days. But don't increase the amount of water you deliver to your plants. If you're gardening on a slope, overwatering can be particularly bad, because the high ground will likely receive very little water, whereas the low ground will quickly become saturated. If that describes your situation, it's best to cycle your sprinkler on and off. Water until you see runoff at the bottom of the slope, then turn it off. Wait for the water to soak in, and water again. Repeat the on/off process until you feel the water is fairly evenly distributed on the slope. And as always, water early in the morning to minimize fungal diseases, try to avoid watering plant leaves for the same reason, and verify the amount of water you're delivering to plants. The simplest, albeit low-tech way of doing that is by setting cups out on the lawn or in garden beds. Ideally, you should provide about an inch of water to the lawn and gardens each time you water. - Stop pruning. Pruning, like fertilizing, increases new growth at a time when plants would just as soon barely grow at all.
And although summertime pruning is perfectly okay, it's best to back off when temperatures are really hot. - Stop planting! The survival rate of newly planted plants drops dramatically as temperatures rise. That's true even of so-called drought-tolerant plants like maiden grass. Of course, that's more of a concern for southern gardeners, but even northern gardeners experience occasional blasts of extreme heat.
- Cut back on mowing. Many turf grasses slow their growth rates in response to heat waves, which means you shouldn't have to mow as often. And when you do mow, cut the grass high, and try to do so early in the morning or in the evening. Mowing during the heat of the day puts a lot of stress on the grass, not to mention the mower.
- Think twice before using certain garden products, especially those that are oil-based such as horticultural oil or neem oil. When temperatures are above 85-degrees F or so, oil-based products can actually burn leaf surfaces. And sadly, the burning can fry a plant to a crisp.
So just what should you be doing in the garden during hot spells? The answer, says James, is as little as possible. "Besides watering--and perhaps adding a fresh layer of mulch to garden beds--it's a good idea to cut back on garden chores during periods of extreme heat, not only for the benefit of your plants but for your benefit as well," says James. "Gardening in extreme heat can be dangerous. And besides, when it's 90 or 95 or 105 degrees outside, what would you rather be doing--gardening outside or relaxing inside?" | |
)