University of Vermont Extension 
Department of Plant and Soil Science

Summer News Article

 HARVESTING THE GARDEN AND OTHER AUGUST TIPS   By Dr. Leonard Perry, Extension Professor

Dr. Vern Grubinger, Extension Associate Professor
University of Vermont

If you polled gardeners as to their favorite month, many would vote for August. Not only is the weather pleasant, but almost everything in the garden is ready to harvest, and most of the gardening chores are now behind you. And it's not too late to put in second plantings of some crops like lettuce, peas, and kale, provided you do it in early August and keep the planting well watered.

Although the gardening season is drawing to a close, you will need to continue to keep an eye out for insect pests such as the squash bug and the striped cucumber beetle, which can feed on and damage young cucurbit fruits. A few new pests may arrive this time of year, including the corn earworm and the tomato hornworm.

The hornworm is a three-inch long, green or brown caterpillar with eight curved stripes and a characteristic "horn" sticking up from its backside. It's a voracious eater, being partial to the leaves and fruit of tomatoes, eggplants, and peppers, and has been known to strip a plant virtually overnight if left uncontrolled. Its coloring provides good camouflage, so you will have to be diligent in your search for this pest. Hand pick and drown in soapy water or snip in half. Control the smaller worms with B.t. (Bacillus thuringiensis), a biological control. You may find hornworms that have been attacked by a tiny parasitic wasp, which attaches its white cocoons to the outside of the worms.

Late July and August are prime picking times for sweet corn, but be prepared for the arrival of corn earworm, which migrates on storm fronts from the South. It is also called tomato fruitworm or cotton bollworm, depending on what crop it's eating.

Soon after arrival, the adult moths lay eggs on fresh corn silks, then the larvae feed in the tips of the ears. Corn varieties with poor husk cover of the ear tips are especially prone to damage. To prevent earworm damage, apply three to five drops of vegetable oil directly to silk channel at the tip of the ear.

The best time to apply oil is four days after the silk starts to grow, when the tips of the silk are just starting to wilt and turn brown. Applying sooner may interfere with pollination, applying later will not provide good control.

For best flavor, harvest corn early in the morning and keep the ears in a cool place until it's time to steam them. To check for ripeness, don't pull back the husks to peek at the kernels. Instead, after the silks turn brown, feel the tips of the ears for fullness. Although you can store corn in the refrigerator for up to one week if husked and placed in tightly sealed plastic bags, it's best cooked on the day of picking. Harvest onions as soon as most of the tops have fallen over. Leaving them in the ground too long only increases the chance of disease in storage. Allow onions to dry on top of the ground for five to seven days or until the "necks" have dried down before storing. Trim the tops to one inch, and store in a cool location in mesh or nylon bags.

In August, raspberry bushes, with the exception of the ever-bearing varieties, can be pruned after the harvest is over. Removing old canes that have just fruited can reduce the chance of getting cane diseases in new growth. However, do not fertilize plantings at this time as that would encourage new growth to become succulent and more susceptible to winter injury. Fall is a good time to apply a thick layer of straw or leaf mulch around raspberries to suppress weeds next spring.

In the flower garden, powdery mildew, a fungus disease that gives leaves a dusty or powdery appearance, is prevalent this month on lilacs, phlox, roses, and many other perennials. Although basically an aesthetic problem that causes little damage to plants, you can apply fungicide now to prevent the disease from spreading. But bear in mind that this will not eliminate the problem.

Next winter, when this summer is but a distant memory, you can bring back the smells of the season by making pot pourri from your roses, pinks, mint, and other fragrant garden herbs and flowers. To make pot pourri, pick the flowers in the early morning soon after the dew has evaporated. Dry petals and flower heads until crisp on a screen or newspaper in a warm spot out of the direct sun. Or use an oven set at its lowest temperature.

Mix with a fixative such as orris root (one tablespoon per quart of petals) to preserve the flavor, then age in a covered jar in a dark spot for three weeks to allow the rich fragrance to develop. Store in an airtight container to enjoy later this winter.

You may want to pick and dry rose hips, after the flowers on your rugosa roses fade, to make rose hip tea. The hips are the fruit of the flowers and are high in Vitamin C.

Other activities for August: fertilize lawns and reseed bare spots; take cuttings from tender perennials and annuals, such as geraniums and coleus, that you want to overwinter; plant a cover crop, if the garden is done producing for the season.

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