I have a “stick them wherever they’ll fit” attitude towards onions, shallots, garlic, and leeks. While most edible alliums grow to be their biggest and best when the soil is rich and the sun is bright, I often start the season with more allium seedlings and sets than ideal space in which to plant them. Rather than tossing the surplus away into the compost bin, I tuck them into any little space I can find, regardless of the growing conditions. The end of the season is like a treasure hunt as I gather these little treats from their hiding spaces underneath bushes, alongside taller crops that grew and shaded them out, and even stuck into pots.
I live in the northeast and am starting a bunch of mine today underneath lights. The following are a few tips gleaned from my own past blunders and successes to help you get started with yours.
Onions & Shallots: Depending on the type, onions are fairly flexible plants that will tolerate a certain amount of rule-breaking on your part. Bunching onions aka scallions tend to be tougher and can be direct sown outdoors in mid-Spring with some frost protection (a cold frame, bottle cloche, or cover).