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Keeper Crops

How to store the summer harvest for the winter kitchen

Onions in trug

A harvest of several types of onions. In general, red onions and yellow onions are good keepers; white onions are not as good.

During the winter months, when the ground is covered by a thick blanket of snow, there’s something particularly satisfying about still being able to eat food from your garden. There are many summer-grown crops including potatoes, onions, garlic, beets, carrots and winter squash, can be stored with relative ease to nourish you right through until the next growing season. Even a modest-size garden can yield a substantial crop of winter keepers.

To be successful storing these keeper crops at home, here are a couple factors to keep in mind:

  • Some varieties store better than others, so be sure to seek out the ones that are known to be good keepers.
  • Crops that are harvested at their prime – not before or after – store best. Time your plantings so they mature at the close of the season.
  • Only first quality, unblemished produce is suitable for storage.
  • Optimum temperature and humidity for storage varies by crop, so be sure that the crops you plan to store match the storage conditions you can provide.

Potatoes

There are so many wonderful kinds and colors of potatoes to choose from: fingerlings, bakers, boilers, white, yellow, pink, red, and even blue. All are delicious eaten fresh from the garden, but if you want to store some potatoes for eating in the late fall and winter months, you’ll need to plant varieties that are well-suited to storage as well as to your growing area. Readily available potato varieties known to be excellent keepers include Katahdin, Kennebec, Yellow Finn and Yukon Gold.

Potatoes can be grown in a standard garden row, in a raised bed or in a container such as a Potato Grow Bag. The more foliage your plants have, the more good-sized tubers you'll harvest, so it's important to keep your plants as healthy as possible.

In late summer when the potato foliage has died back, your potatoes can be dug and “cured” for storage. Curing toughens up a potato’s skin and extends its storage life. Cure the tubers by laying them out on newspaper in a well-ventilated place that’s cool (50 to 60 degrees F.) and dark (so they don’t turn green). After about two weeks, the skins will have toughened up. Rub off any large clumps of dirt (potatoes should never be washed before storage) and cull any damaged tubers, which should be eaten, not stored. Treat the tubers very gently so as not to bruise or cut them. Nestle your spuds into ventilated bins, bushel baskets, a Root Storage Bin or a cardboard box with perforated sides. Completely cover the boxes or baskets with newspaper or cardboard to eliminate any light. Even a little light will cause potatoes to turn green and be rendered inedible. The ideal storage temperature for potatoes is 35 to 40 degrees, though they will usually keep for several months at 45 to 50 degrees.

Onions
Curing onions

Onions should be cured before they are stored.

Wet summers are bad for picnics but great for onions. The more moisture onions get, the larger they grow. Onions also benefit from lots of sun, and will sulk if they’re crowded by neighboring plants or weeds.

Consider starting your onions from seed or young plants, rather than purchasing the little “onion sets” you can buy in the spring. Onions grown from sets rarely store as well as seed-grown onions. Growing from seed also allows you choose a variety that’s known for long storage. Strong-flavored, pungent onions store best (the same chemicals that make onions pungent make them good keepers). There are both red and yellow storage onions; those extra-large, milder onions should be eaten fresh as they don’t store well.

Onion seeds must be started indoors, several months before they’re planted into the garden. Broadcast the seeds so they are about 1/2″ apart and cover lightly with soil. Once the plants are up and the stems have straightened, trim the tops with scissors to a height of about 2″. Repeat every couple weeks (sort of like trimming a Chia pet) until it’s time for your onion plants to go into the garden. These haircuts force energy into the roots and also keep the plants from toppling over. Onions are heavy feeders, so be sure to amend the soil in the planting area with compost and a granular organic fertilizer. Set the seedlings (which may be less than 1/8″ in diameter at the base) about 6″ apart in each direction. Keep them well-watered and well-weeded, and make sure they don’t get shaded by neighboring plants.

In late summer, the leaves of onion plants flop over. This signals that it’s time for the plants to stop growing and start preparing for winter. Allow the plants to remain where they are until the necks begin to tighten and the foliage yellows. If the weather is dry and there’s no danger of frost, onions can be harvested and laid right on top of the soil to dry for a week or two. If the weather is wet or frost is possible, harvest your onions and move them immediately into a protected location where they will stay dry. The floor of the garage or a covered porch works well. Spread the onions out in a single layer and let them “cure” for two weeks. During this time the necks will wither and turn brown, and the papery skins will tighten around the bulbs. Once the necks have dried and there’s no more moisture in the stem or leaves, you can bring your onions indoors and store them in mesh bags or bushel baskets. Keep them cool (35 to 45 degrees F.) and away from light. Another technique for storing an abundance of onions: make caramelized onions. For details, read Making Caramelized Onions.

Garlic
Garlic

A perfect bulb, just after harvest.

Home-grown garlic is a valuable crop. It's easy to grow all you need for year-round use, and the quality just can't be beat. There are lots of different types of garlic available now — read the seed catalogs carefully and choose one that's well-suited to your location. Cold-climate gardeners usually grow stiff-neck varieties, which are hardier. In warmer climates, the soft-neck garlic varieties (which can be braided) are more popular.

Garlic doesn't require much space. A 2 ft. x 12 ft. bed can yield enough garlic for a family, with plenty of extra heads to plant the next year's crop. Cold-climate gardeners plant their garlic in late fall for harvest the following summer. Warm-climate gardeners may find that a late-winter planting (February to March) is best. You can even grow garlic in a Garlic Grow Bag, which is 24" diameter x 8" high. Each bag hold 18 to 20 cloves.

For more information, read the article Planting and Harvesting Garlic, which includes slideshows that show you how.

Plant individual garlic cloves (the bigger the clove you plant, the bigger the head you'll harvest), setting them 4-5″ apart in all directions and just deep enough to cover the top of the clove. Water thoroughly. After the first hard frost, cover the entire bed with straw. Remove the mulch in early spring.

Garlic has the same growing requirements as onions. Keep the plants weeded and well-watered, and give them lots of sun. Calculating the correct harvest time is a little trickier. Dig the plants when the second set of leaves begins to yellow, which may occur as early as July. If you wait too long to harvest, the cloves will begin to separate as they dry, and the heads won't store as well.

Cure your garlic in a dry, dark place just like you would onions. Sort out and save the biggest heads for planting next fall. By planting only the biggest cloves, you'll gradually get bigger and bigger heads each year and will never need to buy garlic again.

The optimum long-term storage temperature for garlic is 35 to 40 degrees F. In warmer temperatures, garlic will begin to sprout. Dryness and complete darkness are essential.

Winter Squash
Squash in raised beds

Squash can be grown in raised beds, but they should be allowed to ramble outside the boundaries of the bed. Another option is to train the vines on sturdy trellises.

Winter squash are fun to grow and easy to store. There are dozens of varieties, from the traditional acorn, Hubbard, butternut and buttercup, to spaghetti, delicata and golden nugget. Pie pumpkins, too! As with other storage crops, some squash varieties store well and some don’t, so choose accordingly.

Squash plants take up a lot of space, but they're not fussy about where they grow. You can usually plan on harvesting one or two good-sized squash from each plant. The usual recommendation is to put two to three plants (or seeds) in a little group, and space these “hills” about three-feet apart.

Don't plant your squash until the soil has warmed and all danger of frost has passed. Young squash plants appreciate protection from insects and harsh weather, and will thrive under garden fabric (row cover). Fertilize at planting time, then forget about the plants until the first light frost, when the leaves will die back and reveal your crop.

For long storage life, when harvesting winter squash it's important to leave some of the stem attached to the fruit. The best way to ensure this happens, is to use a stout knife or pruning shears to separate the stem from the vine. After harvesting, let your squash cure in a warm place (75 to 80 degrees F.) for 10 days or so. When ready for storage the outer skin should be very firm.

Store winter squash in a cool (to to 60 degree F) place that’s well ventilated. Humidity should be relatively low: 30-50%. Check your stored squash monthly to identify and use up any fruit that shows sign of decay.

Beets and Carrots

For winter storage, choose beet and carrot varieties known to be good keepers. Vegetables store best when they're harvested at — not past — maturity. This is especially true for beets and carrots. In most areas, this means that crops intended for winter storage are not sown until late June or July.

To maintain good eating quality, carrots and beets need to be kept at a constant temperature of between 32 and 40 degrees F, and at 90 to 95 percent humidity. There are three ways that home gardeners can provide these ideal storage conditions: in a refrigerator, in moist sand or right in the garden.

To store these crops in a refrigerator or in sand, start by harvesting the roots. Handle them gently to avoid bruising or nicking. Use scissors to cut off all but 1/2″ of the foliage. Rub the roots gently (do not wash them in water) to remove most soil. Don't cut off the root end because this will invite decay.

For refrigerator storage, lie similar-sized, same-variety vegetables in a single layer in gallon freezer bags. Remove as much air as possible before sealing each bag. Stack bags flat on a shelf or in a drawer in the refrigerator. Check monthly for decay and use those first. Beets will stay hard and sweet for five months or more; carrots should last almost as long. Should there be fine root hairs or a little decay, simply peel this off; the root itself will be fine. Carrots and beets can be shredded raw into salads, or can be parboiled, added to soups or stews, or roasted.

A second technique is to store these crops in moist sand. Prepare the roots as above. Moisten clean sand in a large container or wheelbarrow. Pack the vegetables into a tub, wooden box, 5-gallon bucket, plastic-lined cardboard box, or a Root Storage Bin. Start by placing several inches of moist sand on the bottom of the storage container. Lay vegetables on the sand in a single layer, not touching each other. Cover them completely with sand and continue layering until box or bin is full. Top with a layer of moist sand. Container will be heavy when full, so plan accordingly. Remove the stored vegetables as needed.

A third technique (for cool climates) is to store these crops right in the ground. Before hard frost, cover un-harvested carrots and beets with a 12-18″ layer of straw or leaves. (The shoulders of beets are susceptible to frost damage, so be sure to cover them before heavy frost). Lift back the mulch and harvest as needed. If spring comes before all the roots have been harvested, dig and use them up before the soil begins to warm.

How about storing those lesser-known root crops? Rutabagas store well in the refrigerator; prep and store as for beets and carrots. Parsnips may be stored in damp sand or can be left in the ground under mulch. Celeraic can be stored in either the refrigerator or in damp sand.

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