Start indoors early, 12 weeks before last frost. Sow seeds about 1 inch apart. Onions are very susceptible to damping off, so do not over water and keep the good air flow where you are growing your seedlings. Once onions are 3 inches high and about 1/4 inch thick, they can be brought outdoors to harden off. After hardening off, transplant seedlings at 4 inch spacing, or in groups of 3 at 12 inch spacing. Onions require rich, loamy, weed free soil and plenty of water. Weed onion patch often. Pulling large weeds can dislodge onions. Once the tops have started to yellow and flopped over, pull onions and let cure for 1-2 weeks in a warm, dark place. Cut the tops off and store in a cold, dry, dark place until use.