Summer heat, humidity bring vegetable gardening woes
You put forth massive amounts of time and energy to create a garden abundant with vegetables worthy of a few prizes. You expected tomatoes that would be the envy of the neighborhood for your dinner table.
But as days turn warmer and more humid, local Master Gardeners say you might find evidence you’re not the only creature who wants the nutrients found in your home-grown veggies.
Winged visitors, viruses or temperatures may already have begun waging war against you, and you hunger for a victory.
Perhaps, all is not lost.
Some of Clemson University Extension’s Master Gardeners are familiar with the creatures you’re probably seeing and the harm they can cause. They’ve also got tips about what you can do about them. They shared some ideas for a few of the more popular produce picks in Lowcountry.
It can get so hot that tomato plants become dried out, Darren Sheriff says. When they are watered, their cells don’t grow fast enough to absorb the liquid and their skin will rupture. “That splitting exposes the fruit to disease and decay organisms. If nothing is done, mold will appear in a couple of days.”
If a tomato plant is growing in a container, pick the pot up, says Sheriff. If it feels very light, it’s too dry and needs water. If it’s growing in the ground, stick a finger from 1 to 11/2 inches into the soil to see if it feels dry.
Plants in both sandy and clay soil will experience the dryness, but the challenges to those with sandy soil will be much greater. Mulching will help retain moisture.
The tomato horn worm, as big as your thumb and up to four inches long, can be another problem, Sheriff says. It can completely defoliate a tomato plant in a couple of days. Without leaves to produce chlorophyll, the plant won’t produce more fruit.
“If you are lucky, it might start to grow again, but it will be set back,” says Sheriff.
Squash & zucchini
Gardeners growing yellow squash and zucchini will begin to see the squash vine borer very soon, says Ron Coffey.
“The pest looks like a little grub and comes up from Florida starting June or July. Close observation of the plant is required to guard against disaster.”
Those growing squash should check around the main plant stem for a small hole about 1/6-inch in diameter that’s surrounded by frass, excrement or debris that looks like saw dust, Coffey says. Left unchecked, the squash vine borer can cause total plant failure.
“You go out one morning the day after the plant is looking great and it will be wilted,” Coffey says. “Those fortunate enough to find the egg casings or spot the entry hole may be able to make an incision with a single edge razor and pull it out.”
Squash growers should also watch out for powdery mildew when its hot and humid, Coffey says. It’s especially important to watch those in containers because they may need to be watered in the middle of the day. It’s best to use a watering can or soaker hose to keep leaves dry.
Cucumbers may begin to suffer from powdery mildew, downy mildew and pickle worm, says Nancy Limata.
“With all the recent rains, gardeners are going to have problems.”
Powdery mildew usually appears as a grayish white powder on the upper leaf of the plant and may cause the vegetable to be stunted, according to Clemson University Extension.
Downy mildew is a fungus that begins as small yellow areas that expand and become brown.
“The pickle worms are little green worms that bore into the cucumbers and hatch,” Limata says. “Once you have a hole in the cucumber and see something going around inside, the thing to do is to throw the cucumber out. The key to avoiding it is making sure plants get enough water.”
Gardeners who have not trained their climbing beans could be having problems right about now, says Jennifer Schlette. As the beans are watered, tiny pests on the ground or on one plant can be splashed on to others. Others will fly onto the plants.
All will feed on the plant and stunt growth of the vegetable, she says.
They include large numbers of aphids, tiny bugs that come in a range of colors; female Mexican bean beetles, which resemble lady bugs, are coppery brown and will lay a cluster of yellow seeds on the underside of the leaf; the bean vine borer, a worm that attacks the plant at the ground level; and the big black grasshopper with yellow stripes, which can arrive like locusts.
“If you see any of them, the best thing to do is kill them immediately, but that can be a full-time job. You can also use natural and synthetic pesticides, the most common and readily available being (Bacillus thuringiensis).”
Viruses living in the soil, such as the mosaic virus, also may attack the beans and must be treated with an herbicide or fungicide, Schlette says.
Reach Wevonneda Minis at 937-5705.