Tiny pearl onions are mild-flavored and about the size of a small marble. Boiling onions are about 1 inch in diameter and mildly flavored. They're cooked as a side dish, used in stews and pickled. When buying onions, choose those that are heavy for their size with dry, papery skins with no signs of spotting or moistness. Avoid onions with soft spots.
Humidity breeds spoilage in dry onions.
Once cut, an onion should be tightly wrapped, refrigerated and used within 4 days. Freezing the onion for 20 minutes before chop-ping helps, but then so does wearing safety goggles. Onions contain a fair amount of vitamin C with traces of other vitamins and minerals. It is used as a seasoning. My preference is granulated onion.