Gardens, gardeners feel the heat as summer winds down

Beloved raspberry patch, much improved after days of watering by hand. Unfortunately, the birds noticed the improvement, too.

Beloved raspberry patch, much improved after days of watering by hand. Unfortunately, the birds noticed the improvement, too.

Is it just me or did the last part of summer feel excessively hot and rainless in Dorchester County this year until we finally got a downpour on Monday? My electric utility, which prints on its invoice the average temperature for the billing period compared with the same time the year before, agrees.

Delmarva Power tells me the daily average temperature from mid-July to mid-August and from mid-August to mid-September rose three degrees from the same months in 2015.
But long before the electric bill arrived, my beloved raspberry patch indicated, by means of drooping leaves and ever smaller berries, that something was amiss. The sad spectacle galvanized me into action. Judging I could no longer “let Nature take its course” on days when the heat and humidity hit the unbearable 90s, I began a daily early-morning slog between rain barrel and raspberry patch, watering can in hand. (Yes, I realize it’s time to install an irrigation system.)

A few days of that brought a miraculous change. The canes stood up straighter, the leaves plumped out and regained their deep green color, and little white flowers appeared, along with a host of pollinators – bees, wasps, moths, hummingbirds and the occasional butterfly. Not to mention the return of juicy, much larger berries, reward enough to keep any gardener on the job.

Although the Maryland Department of the Environment describes rainfall as normal in southeastern Maryland this year, a study of the state’s potential weather problems by Oxfam (a charity known better for trying to halt starvation around the world) found “Baltimore and Dorchester Counties have elevated risk levels associated with drought.”
Not only that, “more than half the state experienced extreme drought conditions between 1978 and 2007,” according to Oxfam’s “Fact Sheet/Maryland, The Social Effects of Global Warming,” which appears online.

Commercial growers encounter fewer problems with hot, dry spells than do home gardeners because they have irrigation in place and, in some cases, use shade cloth to protect their plants, according to Michael J. Newell, senior faculty specialist and horticultural crops manager at the University of Maryland’s Wye Research and Education Center in Queenstown. Even at the Wye Center, which conducts research on plants and crop growing techniques at a bucolic site covering many acres, “In late July and August, up to the present, the rain shut off, it’s been rather dry,” Mike Newell said.

For home gardeners, keeping their gardens watered at such times is crucial. Extreme heat can cause the flowers on tomato plants to abort, he said. On sweet peppers, it can cause flowers to drop, reducing the plants’ production.

An informative article on the Center’s website notes peppers need lots of sun, but afternoon shade, and “will not produce well in extreme heat for extended periods.” Peppers need “consistently wet soil” and can be cooled “with a mist of water.”

Unusually hot spells can also make fruit and vegetables ripen faster than normal. This year, at the Wye Center, “sweet corn advanced by about three weeks,” Mike Newell noted. Plants can get heat scald from the sunshine and sunburn on their fruit, as well. “In our orchard here, sunburn is an issue. It can cause softness of the fruit and uneven ripening.”

On red fruit, “the sun side shows color faster than the shade side, it gives the fruit an off color.” On apples, for instance, “it seems like it [sunburn] cooks the tree, and the flesh is a lot softer. Dryness stresses the plant overall and can cause premature fruit drop,” he added. This is particularly true for apples and pears.

As for how today’s weather can influence your plants’ future production, if brambles – raspberries and blackberries – don’t get enough water now, their canes will be shorter and their fruit smaller next year. On perennial strawberry plants, “Flower buds are forming now, they start initiating flowers now for next year. If they don’t have enough water now, next spring the berries will be smaller, although they will still have plenty of berries,” Mike Newell said.

If, like me, you thought fruit plants and trees waited until spring to produce flowers, it’s a revelation to hear that the long, involved process begins as early as Fall. “Most of our deciduous [losing leaves in Fall] fruit trees produce flower buds now. If there’s too little water, it could reduce fruit set next year, because the trees need water to get nutrients.”

Too little water can also cause “physiological problems, particularly in peaches: You can get double, or even triple peaches. They’re not marketable, but they’re still edible.”

Using the d-word for the first time, the specialist warned, “With a late-season drought like now, you might see premature leaf drop which may, or may not, affect winter hardiness. If the leaves drop when they’re still green, it’s a signal there’s a pretty severe deficit [of water]. Normally, green leaves help move nutrients back into the tree for winter. If they drop, the tree’s not getting the proper nutrients that help the tree survive winter. A 30-, 40-, 50 percent leaf drop now could cause possible winter injury if we get into severe cold.”

As for annual and perennial vegetables you may have in your garden now, the key is to keep them watered. They may start flowering sooner than usual. Broccoli crowns may be smaller and the quality not as good. Asparagus spears may be fewer and not as plump. It’s important to keep asparagus crowns moist.

Also remember that anything you plan to direct seed this fall, like spinach and lettuce, may not germinate if there’s insufficient rain, so keep the seeds well watered. “I’m watering every day,” Mike Newell said. “One thing we can control is when it’s not raining, make sure things are watered. Too much rain is something we cannot control.”

There’s a happy thought: A situation we can control. Now, when is this deluge coming down from the heavens as I write this on Monday going to stop? When it finally does, happy gardening, Dorchester gardeners!

Editor’s Note: Laetitia Sands is a master gardener in Dorchester County and a regulara contributor to this newspaper.

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