Vegetable gardening Q and A
September 1, 2012
  • /ACES News
  • /Crop Sciences

URBANA – University of Illinois Extension horticulture educator Ron Wolford says that there are some questions about maintaining a vegetable garden that seem to come up every year. He answers them below.

When can I pick my cucumbers?
Cucumbers can be picked at any development stage. If they will be used for pickles, pick them when they are about 2 inches long; for dill pickles, pick them when they are 4 to 6 inches long. If they are going to be used as slicing cucumbers, wait until they are 6 to 8 inches long. Pick cucumbers every other day, preferably in the early morning. Do not allow them to turn yellow. Store them in the refrigerator.

My cucumber vines wilted almost overnight. What’s going on?
Cucumber beetles, which often overwinter in garden debris or weeds around the garden, may have infected the plants with bacterial wilt disease. The symptoms can take weeks to appear and may become noticeable only after there a few small cucumbers on the vines. Nothing can be done to save the vine at this point. Remove all dead plants from the garden at the end of the growing season and cut down weeds around the garden to reduce early-season infestation by cucumber beetles.

How do I know when my onions are ready to harvest?
Onions are ready to harvest when their tops have flopped over and turned yellow. This usually occurs in late August to early September. Dig up the bulbs and let them air-dry for a few days in the sun. Store the onions in a cool, dry place.

My tomato plants are full of flowers, but they keep dropping off. I have just a few tomatoes on the plant. What is wrong?
Very high temperatures, such as those of this summer, can cause tomato plants to drop flowers and not set fruit. The problem usually ends when temperatures drop.

What are the large green caterpillars eating my tomato leaves?
They are tomato hornworms. This is a large, green caterpillar with white stripes and a black horn on the last abdominal segment. They can grow to be almost 4 inches long. Hornworms feed on tomato leaves and fruit. They blend in so well that they often are not noticed until the damage is done. Control them by picking them off by hand.

I have big cracks in my tomatoes. How can I prevent this?
Tomatoes tend to crack when a heavy rainfall follows a dry spell. Mulching the tomatoes will keep the soil moisture uniform, helping to prevent this problem. Try planting tomato varieties that are resistant to cracking, such as ‘Supersonic.’

Why aren’t my sweet corn ears filling out?
Poor pollination can prevent a sweet corn ear from filling out completely. Heavy rains or hot, dry weather when pollen is shedding can have a negative effect on pollination. Corn is wind-pollinated so, for best pollination, plant it in blocks of four short rows.

Why are all the white butterflies flying around my cabbage plants?
The white butterflies are the adult of the imported cabbageworm, a 1-inch-long caterpillar that makes large holes in the leaves as it feeds. The butterflies lay yellow eggs on the upper and lower sides of the cabbage leaves. Cover the cabbage plants with floating row covers while the butterflies are active to prevent them from laying eggs, or pick off the caterpillars by hand when they are small. BT, a safe biological control, can be used. Spray the plant every 7 to 10 days, right up to the day of harvest if necessary.

Are squash blossoms edible?
Squash blossoms can be eaten raw or cooked. Harvest the male blossoms for eating. Female blossoms will have a small swelling just below the petals; the stem of the male blossom has no swelling. Cut the blossoms at midday when they are open, leaving an inch or so of stem. Rinse the blossoms in cool water and store in ice water in the refrigerator. They can be batter-fried.

I am a new gardener. What are some things I can do in my vegetable garden to reduce insect and disease problems?
Following good gardening procedures will reduce the need for pest controls. Choose a location for the garden that gets at least 6 to 8 hours of sun. Water the vegetables without wetting the foliage by using drip or soaker hoses. This keeps the foliage dry and reduces disease. Have the soil tested and add organic matter to it each year. Plants grown on good soil are more likely to be healthy and able to withstand insect and disease problems.

Choose disease-resistant vegetables for next year’s garden. Don’t plant the same vegetable in the same spot year after year. This just invites disease and insect problems. Spacing vegetables properly and caging, staking, and trellising vegetables will provide good air circulation around the plants and help to reduce foliage disease.

To catch problems early, scout the garden a couple times a week for insect and disease problems. At the end of the gardening season, remove all dead and dying plants, especially those that had any insect and disease problems. Removing the plants will reduce overwintering sites for insects and disease.

For more information, check out the University of Illinois Extension website, Watch Your Garden Grow, at: