Vegetables and fruits should be harvested throughout the season, as they reach ideal maturity. Timely, regular harvest not only means better products, but spreads the harvest season and may improve yields of some crops. Whether harvested from your garden or purchased from the grocery store or farmers market, fruits and vegetables need to be stored properly for best quality
Some of our crops can store for extended periods of time. But how can you tell when they are ready to be harvested? What are the best conditions to store our homegrown fruits and vegetables? Choosing fruits and vegetables at the "peak of perfection" eludes many gardeners. Harvesting at the right time is only part of the process – proper storage is vital for keeping garden freshness as long as possible.
Different fruits and vegetables need different storage conditions. Temperature and humidity are the main storage factors to consider; there are three combinations for long-term storage: 1) cool and dry (50-60 degrees F and 60 percent relative humidity), 2) cold and dry (32-40 degrees F and 65 percent relative humidity), and 3) cold and moist (32-40 degrees F and 95 percent relative humidity). For cold conditions, 32 degrees F is the optimal temperature, but it isn't easy to attain in most homes. Expect shortened shelf-lives for your vegetables as storage conditions deviate from the optimal, as much as 25 percent for every 10 degrees F increase in temperature. Some vegetables, such as cucumbers, peppers and tomatoes, require cool (55 degrees F) and moist storage. These conditions are difficult to maintain in a typical home, so expect to keep vegetables requiring cool and moist storage conditions for only a short period of time.
Where can we find the different storage conditions needed in a typical home? Basements are generally cool and dry. If storing vegetables in basements, provide your vegetables with some ventilation. Harvested vegetables are not dead, but still "breathe" and require oxygen to maintain their high quality. Also, be sure they are protected from rodents.
Home refrigerators are generally cold and dry (40 degrees F and 50-60 percent relative humidity). They can be used for storing small quantities of fruits and vegetables. Most often we only store short term in refrigerators but they will work for long-term storage of garlic and onions, but not much else. Putting vegetables in perforated plastic bags in the refrigerator will provide cold and moist conditions, but only for a moderate amount of time.
Unperforated plastic bags often create too humid conditions that lead to condensation and growth of mold or bacteria. Also remember that vegetable or "crisper" drawers provide slightly warmer storage than the main part of the refrigerator, so they are not always the ideal place to store our fruits and vegetables. Sometime gardeners buy old refrigerators for storage; automatic defrost models remove moisture, so manual defrost types are better.
When cool storage is indicated, a root cellar storage area is convenient. It will provide cold and moist conditions. Again make sure to provide ventilation and protection from rodents when storing vegetables in cellars. Materials such as straw, hay, or wood shavings can be used as insulation. If using such insulation, make sure that it is clean and not contaminated with pesticides.
Several vegetables benefit from post-harvest curing. Curing allows the skins to thicken, reducing moisture loss and affording better protection against insect and microbial invasion. Curing is usually accomplished at an elevated storage temperature and high humidity. An enclosed home storage area with a space heater can provide the conditions effective for curing some crops.
When harvesting vegetables, be careful not to break, nick, or bruise them. Remember the less you're vegetables are handled, the longer they will last in storage. Also only harvest vegetables of high quality. Rotting produce cannot be stored for very long, and could spread disease to other stored vegetables.
Following are some recommendations for handling some specific fruits and vegetables:
Potatoes: Late crop potatoes are best for long-term storage. Harvest your potatoes when tops have yellowed or died. Do not leave in ground exposed to high soil temperatures. After harvest, cure potatoes about one week in a shaded, well-ventilated place (open barn, shed, or garage) or by holding them in moist air for one to two weeks at 60 to 75 degreees F. Lightly cover during curing to help retain moisture.
Remove diseased or damaged potatoes as bruises encourage rots to develop. After curing, lower the storage temperature to about 40 to 45 degrees F, ideally in a cool, dark basement or cellar. Do not wash potatoes before they are put into storage and avoid chilling below 40 degrees F. Store the potatoes in the dark to prevent greening.
Sweet potatoes: Harvest in fall before frosts and freezing temperatures. Handle carefully to avoid bruising while digging. Cure one week in warm, humid conditions (temperature 80 to 85 degrees F and 85 percent relative humidity), then store in a warmer location, always above 50 degrees F. Storage life is four months.
Onions: Harvest onions when the tops have fallen over and necks have shriveled and are drying. You may crush or bend necks when about half the crop has fallen over naturally. Cure onions after harvesting by spreading them in a single layer on screens in the shade or in a well ventilated garage or shed for one to two weeks or until the tops are completely dry and shriveled. Dry thoroughly so no "juiciness" remains in neck before storing. Trim tops back to one inch and store onions in shallow boxes, mesh bags or hang in old nylons in a cold, dry well-ventilated room. Storage life is three to four months.
Sweet and hot peppers: Harvest when fruits are firm and full size. Mature, green bell peppers can be kept for two to three weeks if handled properly. Firm, dark green peppers free of blemishes and injury are best for storage. Harvest before frost to avoid damage to the fruit. If red peppers are desired, leave on plant until red color develops.
Hot peppers are easiest to store after they are dry. Peppers can be dried by pulling the whole plant and hanging them upside down in a sunny, warm place or by picking the peppers from the plants and stringing them together. Store dried peppers in dry, cool place (usually basement) for up to one year.
Tomatoes: With care, mature green tomatoes (about normal size, with whitish-green skin color) will keep and ripen for about four to six weeks in the fall. Harvest tomatoes from vigorous vines, tomatoes from nearly spent vines are more subject to decay. Harvest fruit just before the first killing frost. To store, pick tomatoes and remove the stems. Then wrap each tomato in newspaper and pack fruit one or two layers deep in shallow boxes. Check for ripeness each week and remove fruits as they ripen. Ripe tomatoes will keep about one week in refrigerator at 45 to 50 degrees F.
Pumpkins and winter squash: Harvest mature fruit with hard rinds (ones that resist fingernail pressure) just before frost. Leave the stem on when cutting from the plants to prevent decay. Cure for 10 days at 80 to 85 degrees F. Store the squash on shelves in single layers to allow air circulation. Storage life is two to three months. The one exception is acorn squash: store at 45 degrees F after harvest. (Curing acorn squash will lead to stringiness.)
Watermelon: Harvest when the underside of the fruit turns from whitish to yellowish. On some varieties, the tendril and vine usually dies when fruit is mature. Thumping an immature melon gives a ringing, metallic sound, while mature melons give a dull thud. Watermelons will store at room temperature about one week, at 45 to 50 degrees F for two to three weeks.
Muskmelons & Cantaloupe: Harvest when stem slips easily from fruit. Lift melon – if ripe, it should separate easily. You can store ripe melons up to two weeks in plastic bags in refrigerator.
Root crops: Beets, carrots, rutabagas, parsnips and turnips can be left in the ground into late fall and early winter. A heavy mulch of straw will prevent the ground from freezing so the roots can be dug when needed. Many people prefer the taste of these crops after they have been frosted because their flavors become sweeter and milder. But make sure to finish harvesting these crops before the ground freezes solid, or you'll have to wait until spring to dig them out. Once dug, wash roots; trim tops to 1?2 inch, place in perforated plastic bags and store in refrigerator or cold, moist cellar or pit. Root crops will generally store three to five months.
Apples: Late maturing apples are best suited for storage. Store in baskets or boxes lined with plastic or foil to help retain moisture. Always sort apples carefully and avoid bruising them. The saying "one bad apple spoils the barrel" is true because apples give off ethylene gas which speeds ripening. When damaged, ethylene is given off more rapidly and will hasten the ripening of other apples in the container. Apples often pass their odor or flavor to more delicately flavored produce and the ethylene given off by apples can accelerate ripening in other crops. Apples should be stored separately as the ethylene gas will also hasten the ripening of other fruit.
Because of their sugar content, apples can be stored at 30-32 degrees F without freezing the tissue. In general, apples ripen about four times as fast at 50 degrees F as at 32 degrees F, so they should be kept as close to 32 degrees F as possible for long-term storage.
Pears: For good flavor and texture, pears, except for "Seckel" must be ripened after harvest. Pick pears when they are fully mature, and firm in texture. Fruit is ready to harvest while it is quite firm but the color has lightened to a pale green. It should part easily from the branch when you lift up on the fruit and twist. Pears left to ripen on the tree tend to become grainy or stringy. The center also may turn brown before the exterior shows deterioration.
Pears ripen quickly after harvest when held at 60 to 65 degrees F. Ripening will take one to three weeks, depending on the type of pear. After ripening, pears should be canned or preserved. To keep pears longer in storage, sort for defects after picking and place sound fruit into cold storage at 29-31 degrees F and 90 percent humidity. Ripen small amounts as needed, by moving them to a warmer location, 60-65 degrees F. Too high of temperatures (75 degrees F and higher) will cause the fruit to break down without ripening.
I hope that the information provided will help you to enjoy your harvest for a long period of time. For more information feel free to contact the Yankton County Extension Office.