Stop watering in the beginning of August to mature the bulbs in dry soil. After half the tops have fallen, push over the remainder, wait a week and lift the bulbs. Curing is essential for long storage: Spread bulbs out in a single layer in an airy spot out of direct sunlight. Once no more green is visible on any of the leaves, and they are dry and crisp, the onion is cured. If weather is poor, cure indoors. Storage: Keep onions in mesh sacks or hang in braids so they get good ventilation, and hang sacks where air is dry and very cool, but not freezing. Check them regularly and remove any sprouting or rotting onions. Well-cured storage onions should keep until late spring.