Keep storage onions in a cool, dark, and dry place. Moisture and light lead to mold (ew) and sprouting (annoying, though not a deal-breaker), so stow your storage onions (red, yellow, and white as well as shallots and the diminutive pearl and cippoline) in a dry, well-ventilated basket, bin, or large bowl.
Ideally, onions should be stored in a cool, dark place between 45 and 55 degrees F. Whole, raw onions will last two to three months when stored in a cool, dry place. Places that provide these conditions may include your cellar, pantry, unheated basement, or garage.
Now when it comes to fresh onions, like spring onions with their green tops attached, or sweet onions, like Vidalias and Walla Wallas, refrigeration is your best bet for long-term storage.
Onions should be stored at room temperature, away from bright light, and in a well ventilated area. Onions are packaged in mesh bags because they like to breath. Avoid keeping them in plastic bags.
The fridge is a cold and humid environment, which can cause onions to soften and spoil. The best place to keep whole onions is somewhere dark, cool, dry, and well-ventilated.
The ideal temperature to store onions is around 45 to 55 degrees, according to Matthew Yee, chef at Farm to the People. For this reason, he says it's best to store onions in a cool, dry place like a cellar, pantry, or even a garage.
Place the container in a dry, dark spot, like in the back of your pantry or inside a cabinet. Sunlight can affect temperature and humidity, causing onions to go bad. Properly stored whole onions will stay fresh for 6 to 8 weeks.
Whole onions keep for 2 to 4 weeks at room temperature and more than 3 months if refrigerated. No matter the storage spot, onions need good airflow, so they don't grow mold.
Do not wrap onions in plastic or store in plastic bags. A lack of air circulation will reduce shelf life. Onions should feel firm and dry, be free of gray or black mold, and should not have any visible sprouting.
It's also possible for onions to absorb their flavor from plastic bags, so it's best to use glass jars or metal containers for storage instead.
What you don't want is to have your potatoes and onions in close proximity, as gases from the onions can hasten sprouting in potatoes. Kept in the dark: Davison says your potatoes should be stored inside a paper bag in a cool, dark, dry place. And as mentioned above, away from onions and their sprout-encouraging gases.
For maximum freshness, onions should be peeled before refrigeration. If stored whole and unpeeled in the fridge, they will spoil within 7-10 days due to moisture absorption which can cause them to become mushy. It is best practice to store diced or sliced onions for up to two weeks for optimal flavor preservation.
Generally speaking, onions should last between seven and ten days in your refrigerator and six to eight months in your freezer, but all of that can depend on how they are stored. Chopped onions tend to keep well in your fridge, but they should be stored correctly.
Don't keep whole onions in a plastic bag.
Trapped moisture can lead to mold. You want onions to breathe. If they're in a plastic bag, take them out of the bag. Ideally, use perforated or mesh storage bins for better air flow to help keep moisture levels down.
TEMPERATURE: These will last the longest in a dark, cool (but not cold), dry storage area. I've successfully kept them in my 65-70ish degree kitchen drawer for up to 3 months. A cool, dark basement is a good choice, if you happen to have one.
Storage rots are caused by fungi and bacteria (Pseudomonas and Erwinia spp.) that live on organic matter and onion debris in the soil. These organisms are common in soil and will attack several different host plants. They become a major problem wherever onions are grown in a short rotation.
Onions also give off a little ethylene. When you put the tomato and the onion together, you increase the presence of ethylene, to the detriment of both. To reduce the ethylene, don't store onions and tomatoes together. (Onions will make potatoes get soft, too.)
Why? Your onions produce and emit ethylene gas, which speeds up the ripening process and can cause nearby potatoes to rot and spoil more quickly. However, garlic, another root bulb, can be safely stored alongside onions with no scary side effects.
Storing potatoes and onions together isn't the best idea. Onions produce a high level of ethylene gas, which will cause potatoes to ripen — and go bad — before you're ready to use them. However, those spuds aren't completely innocent, either; potatoes' high moisture content can cause onions to liquefy and leak.
They are ready to store when the skins are papery, the leaves are completely shrivelled up, and the roots are wiry and dry. At this stage you should cut off the roots and remove any loose skin. If you want to store your bulbs as onion strings, cut the stems to within two or three inches (5-7cm) of the neck of the bulb.
You'll have to store your carrots in the refrigerator, but how you store them can actually make a difference. Raw carrots, when properly stored will usually stay fresh for around 3 to 4 weeks in the fridge. If your carrots are sliced or chopped, you can store them in the fridge and they'll last for about 2 to 3 weeks.