The best way is a root cellar, but not many of us have these in our homes nowadays. All root vegetables need a storage space. This includes turnips, carrots, potatoes and onions. It is recommended to store each separate in their own container.
For onions, dry the skins. After the onions are harvested, spread them out in a ventilated area so that the skins can harden. Do not remove the leaves. Allow the onions to cure for two to four weeks.
Trim the onions. Once the stems are completely dry, use sharp scissors or a knife to trim the roots from the onions.
Discard onions that still have green stems at this point, as well as those that are bruised or have broken paper.
Cut the leaves at least an inch above the bulb, or leave them intact and braid the leaves together.
Choose a cool, dark place to store your onions. The space should have a temperature maintained between 40 – 50 degrees Fahrenheit, or 4 – 10 degrees Celsius. If the space is too warm, your onions will begin to sprout. If the location you chose is too cold, the onions will start to rot.
Dry the onions away from sunlight and humidity. Sunlight can taint the taste of the onions and make them bitter. Lay a tarp in your garage or a shed. The environment should be dry, warm and breezy.
The onions are finished curing when their stems are no longer green. The onions’ skin should be withered around the stem and wrapped tightly around the onions.
Keep the storage space dry. Onions easily absorb moisture, and the wetness in the air will rot your produce. The humidity level should be kept at 65 – 70 percent.
Make sure the space is well ventilated. Keeping air flowing around the onions will help prevent molding and rotting.
For good ventilation, hang the onions in mesh baskets, netted bags or pantyhose.
If you decide to use pantyhose as a storage option, tie a knot between each bulb. Use the bulbs from the bottom, cutting the onion out below the knot so the onion above it stays secure. You can also use string or twist ties in between the onions to keep them separate.
Storing onions in this way allows them to breathe properly. Any moisture they may have already come in contact with will soon evaporate, giving your angiosperms a longer shelf life.
Inspect stored onions regularly. Take a moment every now and then to browse over your onions. Throw out any that have started to rot.
You can still eat onions that have started to sprout. Just chop away the green part before using them in a recipe.
If an onion is slimy or discolored, don’t risk eating it.
Save extra bulbs to plant in the spring.
Store peeled onions in the freezer. Chop your onions and place them in a flat layer on a cookie sheet and freeze. After they are frozen, remove the onions from the sheet and store them in Ziploc bags or storage containers in the freezer. One of the downsides of this option is limited storage space.
Wrap leftover onions and store them in the refrigerator. When cooking, partial onions often remain from preparing the meal. To properly store these remnants for use later, wrap the onion in plastic and place in the vegetable drawer in the refrigerator.
In late summer when the potato foliage has died back, your potatoes can be dug up 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.
Taking the time to store onions and potatoes correctly will give you the chance to use them for a longer period of time. You can even save some to replant again next spring for another crop.