It’s time to plant bulbs again, but I don’t mean tulips. I’m talking about onions.
Typically, onions are a spring-planted crop, sown for harvest in late summer and kept through as much of the winter as possible. But even with good, cool, dry storage conditions, your winter onions eventually turn dark in the center and send out long, green shoots, and there’s a long wait before the next year’s harvest. Who wants to cook without onions? They make everything taste better.
(High Mowing Seeds/HIGH MOWING SEEDS) - Walla Walla onions.
The best way to bridge the onion gap is to plant them now for overwintering. Fall planting is what one normally does with garlic. Garlic goes into the ground in the fall and makes just enough root growth to get established and then be poised for action when spring comes. Timing is important, because you don’t want it to complete its life cycle now. The same goes for onions. Planted too early, they’ll make too much growth and go to seed in the spring rather than forming nice big bulbs. So a September planting is just right.
Some varieties are better for overwintering than others. Walla Walla Sweet, available from High Mowing, Territorial Seed and other companies, has worked very well for us. Another good one is Candy, a day-neutral variety. The cold-hardiest is the aptly named Bridger fromJohnny’s Selected Seeds. Because onion growth is aboveground and is not as winter-hardy as buried garlic’s, it’s wise to give onions some protection in Zone 6 and above by growing them in a cold frame or under quick hoops (low-growing tunnels).
Direct-sowing — without thinning — is the best method. (Look for pelleted seeds to make this easier.) When growth starts, you can thin the extras by harvesting them at scallion size. Steal some of the small bulbs as they form; they are so incredibly sweet and fresh-tasting. It’s best to run a sharp knife just below the bulb to cut the roots, rather than yanking them. That way, you avoid disturbing the ones you are leaving in the ground. Those should wind up with a spacing of three to four inches. In Washington (that’s D.C., not Walla Walla), you should have scallions in April, small bulbs in May and fat, full-grown beauties in June.
The overwintering types are not long-keepers, so use them up. Cut them in half and roast them, basted with olive oil and herbs, to serve warm or as a room-temperature antipasto. Pair them with asparagus, then green peas, then young zucchini in a progression of early garden soups, light but a little creamy. Cook them down, by themselves, into a jamlike relish and bury burgers under it. Do not stint and do not hoard. The late crop will soon be on its way and ready for stealing.
Damrosch is a freelance writer and author of “The Garden Primer.”