Gardening Articles: Care :: Plant Care Techniques
Working with Onion Transplants
by National Gardening Association Editors
Onion transplants may need special care when first planted in the ground. Here are some techniques to keep in mind.
Hardening off transplants is simply getting them used to being outdoors instead of in a warm house. Plants are like people - they can get sunburned, windburned or chilled. To harden off your seedlings, take your flats outside around the time of the average last frost in your area. Set them in partial shade, protected from wind, for a couple of hours the first day. Increase their time outside by an hour or so a day the first week.
Next, place the flats in full sun for most of the day, and if there's no danger of frost, leave them out overnight. If you suspect a freeze, bring them in or protect them well outside.
After a week to 10 days of gradual exposure to the outdoors, your plants will be tough enough to take the shock of transplanting.
Remember: Onion plants are more tender than sets, so transplant after the danger of hard freezes in your area has passed. Light frosts won't hurt them, though.
Before you plant your seedlings, work compost or fertilizer into your soil, then smooth the surface. Putting the transplants in is easy: Lay the plant on your index finger, and push your finger with the onion on it about two inches into the soil. Lift up your finger and the onion just a bit (this gets the roots headed in the right direction), then slide your finger out of the hole and firm the soil around the plant. (You can also use a pencil to make the holes for the plants.) Don't be afraid to transplant small seedlings - even those as small as toothpicks. Even tiny ones can make it.
Direct-Sowing Onion Seed
Sowing onion seeds right into the garden can allows you to skip some transplanting steps. Here's how it's done.
Combine the onion seed with some radish seed (about 5% radish seed) and sprinkle or "broadcast" this mixture in a wide row about 15 inches across. Don't worry too much about spacing - as you harvest the fast-growing radishes (they also serve as row markers) and young onions for early eating or pickling, you'll create plenty of space between the remaining onions for them to grow to full size.
To make sure the seed has good contact with the earth, spread a light layer of soil on top of the seed and firm it into the soil by tamping it down with a hoe or rake.