Knowing when to harvest is important


Grapes and vegetables seemed to be on people’s minds this week.

Q: How do I keep birds from eating grapes as they approach maturity?

A: Ninety-five-year-old Ferren Bunker places brown lunch bags over his clusters. He doesn’t vent the bags, as birds will tear the bags open to get the grapes. He uses straight pins to clip bags over the cluster.

Q: What is causing the freckling of my grape leaves? Grape leaf skeletonizers are not the problem.

A: Grape leafhoppers are causing the freckling. I have a problem with this insect despite all the green lacewings (good insects) working my grapes. You’ll find eggs on the underside of the leaves beginning last month.

The hoppers remove the green contents of leaf cells, leaving behind pale yellow spots or freckling. If you allow the populations to increase, leaves become pale white and eventually drop reducing the production of carbohydrates.

Those who make grape juice from severely infested, leafhopper-damaged plants may end up with vinegar-tasting juices. Use insecticidal soap (organic) to control them. Run your hands through the vines. You can hear the hoppers flying into the leaves attempting to get away.

Q: How do you tell when to harvest Armenian cucumbers?

A: These cucumbers are prolific. They are long, curvy cucumbers that are a pale green. To get the most from your crop, harvest them when they are about a foot long and are the most tender. If you let the cucumbers get too long the plant stops producing them. Once cucumbers, squash and zucchinis set seed, the plant then focuses on seed production, something you don’t want.

Q: When do I pick my eggplants?

A: You’ve been fussing with them for a long time so don’t blow it at harvest time. Eggplants have a small window of harvest time. If they are left to grow too long they quickly turn brown and become spongy and bitter to taste. If you pick them too early they don’t have time to develop their best flavor.

Pick them when they still have glossy sheens on them, with a little give when gently pressed but quickly retaining its shape. If there is no give, then the eggplant is still too young, and if they don’t bounce back they are too mature. Size is not always an indicator of maturity. The fruit bruises easily, so be careful.

Q: Why do some of my eggplants have dark brown leathery bottoms similar to blossom-end rot on tomatoes?

A: Eggplants, peppers and tomatoes are closely related, so they all have the same problem. Blossom-end rot also affects many vine crops such as watermelons. It’s brought on by low concentrations of calcium when fruit set on. It takes water to dissolve the calcium off the soil, so you can trace the problem back to poor water habits at the time of fruit set.

These vegetables require large concentrations of calcium at that time and if they can’t get it, the tissues break down, leaving the leathery black spot. Avoid wide fluctuations of soil moisture by using mulches. If it’s still a problem, foliar apply calcium to the leaves for quicker movement to the fruit.

Q: How do I tell when my watermelons are ripe?

A: You want a creamy-yellow spot where your melon rests on the ground. A white or pale green spot tells you to wait a little longer. Remember, watermelons never improve their quality once they’ve been harvested.

Q: How do you tell when to harvest sweet corn?

A: Growing your own sweet corn is one of the true pleasures of gardening. When the silk turns brown is a good indicator. Or peek under the husks and look at the kernels. You want plump, firm kernels. Check closely as the kernels can become quickly tough.

Q: How do you tell when to harvest potatoes?

A: This can be mysterious because the important developments happen underground. New potatoes are ready when plants finish flowering. Dig around the plants’ edges with a garden fork to avoid damaging those you’ll harvest later.

To harvest large potatoes, let the plant continue growing. Keep hilling up the soil around the plants to prevent sunlight from damaging the tubers. Once the foliage dies, dig your tubers and put them in the garage for a couple of days before brushing the dirt off.

Q: When do you harvest okra?

A: For continued production, pick them daily. Never let them reach the hollow, puffy stage.

Linn Mills writes a garden column each Sunday. You can reach him at linnmillslv@gmail.com or call him at 702-526-1495.