I noticed onion flowers and garlic flowers in my garden last summer. What caused this, and, in the future, should I remove the flowering stems or let them bloom?
Onions are biennial, which means they ordinarily produce bulbs in their first year of growth, then, if left in the garden, they flower and bear seed in their second year. George Boyhan, a vegetable specialist at the University of Georgia extension office, says springtime temperature swings — such as a warm spell followed by a cold snap — can sometimes cause onions to bloom. That’s especially true if cold weather strikes an onion that is approaching maturity, a state usually indicated by seven true leaves. Younger plants with fewer leaves are less likely to bloom early.
What to do? Harvest any flowering onions and use the bulbs immediately, because they won’t keep well. (You can put the pretty flowering stems in a vase with water.) Do not break off the flower stems or leave the bulbs in the ground for later harvest — the bulbs won’t grow any larger, and the broken, hollow flower stems will channel rainwater directly to the bulbs, encouraging rot.
According to Boyhan, onions are regionally developed. To reduce the chance of onion flowers blooming (or “bolting”) too soon, check with your extension service for recommended varieties. Bulb formation is triggered by the amount of daylight, so be sure you are planting the right “day length” type for your area — “long day” onion varieties in northerly latitudes, and “short day” onion varieties in southerly latitudes. Smaller onion sets (less than the size of a dime in diameter) are less likely to bolt than larger sets. (MOTHER EARTH NEWS’ comprehensive, step-by-step guide to growing onions is available at All About Growing Onions.)
Hardneck garlic produces long, curled stems, called “scapes,” in early to midsummer, following a fall planting. Snip off the scapes as soon as they appear, but don’t harvest the garlic bulbs yet. Unlike onions, the flowering garlic bulbs will continue to grow after the scapes have been removed, putting all of their energy into making the bulb. A tasty bonus: You can use scapes from flowering garlic — which have a pleasantly mild garlicky flavor — in soups, salads, stir-fries or pestos. Harvest garlic bulbs when the lower five leaves of the plant have turned brown.
Above: Springtime temperature swings can cause onions to bloom early. Harvest the flowering onions, as they won’t keep well.
Photo By Dreamstime/Jupaule
Vicki Mattern is a contributing editor for MOTHER EARTH NEWS magazine, book editor and freelance magazine writer. She has edited or co-authored seven books on gardening, and lives and works from her home in northwestern Montana. You can find Vicki on Google+.