News Release Distributed 06/11/10

By LSU AgCenter Horticulturists Dan Gill and Allen Owings

June is the peak month for harvesting early-summer vegetables. People grow their own vegetables because of the outstanding quality of freshly harvested produce, and growing your own vegetables is a part of sustainable landscaping. Harvesting at the right stage, however, is essential to getting the best quality vegetables from your garden.

Some vegetables are harvested while they’re still immature. These include eggplants, summer squash, cucumbers, okra and snap beans. Don’t leave these vegetables on the plant too long or quality will quickly decline.

Other crops, such as tomatoes, winter squash, bulbing onions, garlic and sweet corn, are harvested when they’re ripe. For best quality, they must be left on the plant until they’re fully mature – or fully developed in the case of onion and garlic bulbs.

Peppers are unique because they can be harvested in the immature, green stage, which is typical for bell peppers and jalapeno peppers; when they’re fully ripe, which is generally red, or at any stage in between.

You can maintain the best quality if the vegetables are eaten soon after harvest. When harvesting, you are removing a plant part that becomes a separate living entity. As a separate entity, the vegetable uses energy from its stored food reserves and loses moisture through transpiration, which gradually reduces quality. Vitamin content also decreases during storage.

If you can’t consume them immediately, you can preserve the quality of most vegetables by refrigerating them as soon as possible to slow down respiration and water loss. The faster you cool them down, the longer you can store them successfully. To do this, you can place recently harvested vegetables in ice water for quick cooling. Remove them from the water when they’re cold, and then store them in your refrigerator. Exceptions are Irish potato, tomato, melons, garlic and onion, which should be stored at room temperature, although tomatoes and melons can be chilled prior to serving.

All refrigerated vegetables should be used within five days for best quality and nutritional content.

Tips on harvesting

Snap beans should be harvested when pods are about the diameter of a pencil and seeds are very small. If beans are allowed to mature on the plants, they can be shelled and cooked as dry beans.

Harvest sweet corn when the silks turn light brown or darker. You can peel back the shuck to see how well the kernels have developed before removing the ear. The juice of the kernel should be milky when you puncture it with your thumbnail. Sweet corn should be eaten as soon as possible after harvesting for maximum sweetness.

Cucumbers can be harvested at your desired size; however, harvesting should be done before the cucumber begins to lose its green color. When old cucumbers begin to yellow, they’ll have well-developed seeds and become bitter. If the fruit is allowed to mature and turn yellow on the plant, the plant will stop producing new fruit.

Eggplants should be harvested when they are one-third to two-thirds of their full, mature size. The skin should be glossy. If the skin is dull, this indicates over-maturity, and the fruit will be seedy and often bitter. Harvest eggplants using pruning shears because the stem is tough.

Peppers, both sweet and hot, can be harvested at any size or color. Most peppers will turn red at maturity, but some may be green, purple, yellow or orange along the way.

Tomatoes can be harvested any time after green fruit begin to turn pink. Best quality, however, is obtained when fruit fully ripen on the plant. If you harvest early, often to get the fruit out of harm’s way from birds and insects, you can ripen the fruit at room temperature and still expect excellent quality. Tomatoes don’t need light for ripening, so there’s no need to put them in a window.

Okra should be harvested every two to three days. Most types should be harvested when they are young, tender and less than 3 inches long. The pod snaps easily from the plant when it’s harvested at the proper stage.

Summer squash, including zucchini, should be harvested small (one-half to two-thirds the mature size) and immature while the skin is still tender. The more frequent the harvesting, the more fruit the plant will produce. Use a knife to remove the fruit and leave 1 inch of stem attached.

Harvest the pods of Southern peas – purple hull, black-eyed and others – when they’re well-filled and have changed to a light straw, silver or purple color, depending on the variety. They shell easiest at this stage.

Visit LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is near the intersection of Burbank Drive and Nicholson Drive (Louisiana Highway 30) in Baton Rouge, across the street from the LSU baseball stadium. For more information, go to www.louisianahouse.org and www.lsuagcenter.com/lyn.