UNIVERSITY PARK, Pa. -- Successful vegetable storage depends on proper temperature and humidity, gentle handling and starting with high-quality vegetables, says a vegetable specialist in Penn State's College of Agricultural Sciences.

"For best results, harvest vegetables at peak maturity," says Peter Ferretti, professor of vegetable crops. "Select vegetables that are free of disease, insect injury and frost or mechanical damage.

"Vegetables grown in the soil, like potatoes and carrots, will look better if you wash them," he says. "But wash gently so you don't bruise or skin them. If you want to use a small amount immediately, just wash them under a trickle of running water -- the way a surgeon scrubs."

Ferretti describes a simple method for washing large amounts of produce at home:

Place one-bushel of vegetables at a time in a slatted hamper. Submerge the hamper in a tub or container full of water, and soak for 10 to 20 minutes to soften the soil. Lift the hamper and tip it slightly, gently rolling to tumble the vegetables. Spray any remaining soil away with water, then dump the vegetables -- gently, gently -- into clean hampers to drain and dry. After an hour or so, your vegetables will be ready to store.

For best results, store each vegetable according to its special requirements. "Most produce stores best at 32 degrees Fahrenheit, but some -- such as pumpkins, squash, sweet potatoes and green tomatoes -- can be injured below 50 degrees," Ferretti says. "If you have to store crops together, use the higher temperature. But you may reduce the storage life of the lower-temperature crop."

Ferretti suggests some rules of thumb for storing common garden vegetables. These vegetables all store best in darkness or very subdued light.

Store onions in a dry, well-ventilated place around 32 degrees F. Store cabbage, cauliflower, celery, endive and kohlrabi in a moderately moist place at 32 to 34 degrees. "It won't hurt if they're subject to a light freeze," Ferretti adds, "as long as you don't handle them while frozen."

Peppers keep well in a dry place at 45 to 50 degrees, such as an attic, an unheated room or the warmest spot in a refrigerator -- but not in a storage cellar. At or below 40 degrees, peppers can decay in as little as three weeks.

Cure potatoes, winter squash, pumpkins and gourds to keep them from rotting. Curing hardens the skins and heals cuts. Keep them in a moist place for a week or two at 60 to 75 degrees (wounds don't heal at 50 degrees or below). Then, store them in the dark so they don't turn green. As soon as outdoor temperatures permit, lower the temperature to 35 to 40 degrees.

Root crops like beets, carrots, turnips, rutabagas and winter radishes keep best in a humid place, between 32 and 40 degrees. At 45 degrees, they sprout and become woody. The moisture prevents them from shriveling. "For the sweetest root crops, wait until late fall to pick them, so more of the starches can be converted to sugars by the colder weather," Ferretti says.

"Gardeners often end up with a lot of unripe tomatoes just before the first frost," he says. "To ripen them, store them in one layer -- not touching -- in a basement or outbuilding at 55 to 58 degrees. Keep them in a moderately moist place; too much dampness encourages decay."

Choose tomatoes that have already lightened or turned pink. Spread them on a table or in shallow trays. Check regularly to remove ripe or rotting fruits. "It doesn't matter if they're in the light or dark, but avoid direct sunlight." he says. "Don't let temperatures drop below 55, or go higher than 75 degrees. Never store any tomatoes, except cut pieces that should be used in cooking, in the refrigerator where temperatures are always below 55."

Winter squash and pumpkins should be fully mature before going into storage. Cut them from the vine just before the first frost, leaving the stems attached. "Handle them carefully," Ferretti says. "They may look tough, but they bruise easily."

Winter squash and pumpkins (except acorn squash) should be cured at 80 to 85 degrees for 10 days, then stored at 55 to 60 degrees -- the temperature of a typical house basement. At or below 50 degrees, they can get chill damage. Above 60, they dry out and get stringy. Store acorn squash in a dry place at 45 to 50 degrees; they decay quickly at or below 40 degrees.

Dry beans, peas and popcorn store best in a dry place, like an attic, porch or unheated room. Pick popcorn or pods as soon as they mature, then spread them in a warm place to dry. Dry popcorn on the cobs since popping quality depends on moisture content. Once the popcorn pops well by test, store it in plastic bags, tin cans or glass jars to maintain the desired moisture.

Shell dry beans, then use one of the following treatments to protect them from moths, weevils and seed maggots: refrigerate at 0 degrees or below for three or four days, or heat in a 180-degree oven for 15 minutes. After turning off the heat, keep beans in the oven for another hour. Store them in tight containers, such as plastic bags, glass jars or cans.

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EDITORS: Contact Peter Ferretti at 814-863-2313.

Contact:

Kim Dionis kdionis@psu.edu 814-863-2703 814-865-1068 fax