Whether you buy potatoes and onions in quantity or you grow your own, you want them to last through winter, which requires proper storage. Poor storage means sprouting, limp potatoes and rotten, smelly onions. Unless you have very small new potatoes and very small, sweet onions, these vegetables do not benefit from storage in the refrigerator. Instead, they need a cool (not cold), dry place. A few pointers will help you store your potatoes and onions over the winter, or for at least two months.
Look through your potatoes and remove any with brown spots, sprouts or soft spots. Cut out the bad spots and use these right away. It's okay to refrigerate them once the skin has been broken, but they will only last a day or so.
Sort the onions, removing any with sprouts, rotten spots or discoloration. Trim these and use them right away, or put them in the freezer to use next time you make chicken, beef or vegetable stock.
Find clean boxes that have been used for a clean product, preferably not for groceries. Find enough to fill with your vegetables with plenty of breathing space.
Use separate boxes for potatoes and onions. Pour a 25-pound bag of rice in each box, mixing it in with the potatoes. Do the same with the onions. The rice absorbs moisture and keeps the vegetables fresh.
Put vegetables in a cool place like a garage or basement; 50 to 60 degrees F is ideal.
If you have a good source of sand, that is also fine to use instead of rice. Make sure it is clean and dry.
Check your produce through the winter and remove any vegetables that seem limp, are sprouting or look rotten.