Sets are available from seed catalogs, garden centers and hardware stores. The Nitty Gritty on How to Plant Onion Seed. Growing from seed is difficult for many home gardeners because onion germination rates are often poor. Onion seeds can be kept for two years in a cool, dry place such as a properly monitored seed storage box, but fresh first-year onion seeds germinate best. It is just one of those onion facts that the key to growing big onions is early planting, with fertilizer or compost. Onions can be grown from seeds, sets, and plants (transplants). Onion Sets Versus Seeds. Growing Onions from Seeds. Put seeds 1-inch deep. When the seedlings grow to 4 inches in height, they can then be carefully lifted from the flats and transplanted to their permanent places. Help, My Onions Won’t Grow Big – Growing Big Onions. We usually plant a mix of white, yellow and red onions. If you’re a Square Foot Gardener, plant onions 9 per square foot. Growing onions from seed is a little more difficult than growing onions from sets, especially for the new vegetable grower, but seed does provide some compelling advantages over sets. If you're in a milder area, you may be able to get away with starting onion seed directly in the garden. Danielle – growing onions is something I want to add this year, so thank you for this timely post! Plant the onion seed down the line, maybe 1 seed every quarter inch or so. Harvest onions when about half the tops are falling over and dry. Should I Grow Onions from Seed or from Sets? Growing Onions from Seed Onion seed of both white and yellow varieties, can be sown indoors in flats, early in the spring. For those of us that have a real winter, plant onions inside 8-10 weeks before your last frost date in spring (earlier is better). Starting onion plants from seed takes the longest for onions to fully grow, but onion seeds give you the most choices in variety. It can take up to five months of onion growing … We prefer planting onion sets over seed, simply because they establish quickly, and are easier to plant. Soil for onions should be well-drained and high in organic matter. Germination rates fall as the seeds age, and though I have had three-year-old onion seeds that sprouted well, germination is always highest with fresh seeds. Draw 4 furrows about a 1/2" deep the length of the tray. I use a chop stick to help place them. ), and will be ready to start planting by February. Onions can be planted in either the spring or fall. Growing Onions from Seed and Sets. To grow your own onion sets, sow the seeds thickly, and to do so, broadcast them evenly over the bed. It does look easy, and I am less intimidated now about growing from seed. Sets are little dried onions that you can use to get a head start on the onion growing season without the need to start indoor seeds months prior. Onion plants grow well in raised beds or raised rows at least 4 inches high. The easiest way is to plant “sets” (small onions) in the spring. A quick guide to onions. Since onion seed germination rates are bad, gardeners often opt for growing onions from sets. You can grow onions from seed, transplants or small bulbs called “sets.” Plant onions early in spring. Onions are shallow-rooted and require constant moisture for proper growth. Common onion info tells us that it is often easier growing big onions from plants than from seed. To plant: Plant onion seeds when the soil temperatures are at least 45 degrees. Growing from both sets and seed in long-season regions allows for two harvests; one early in summer and the second in late summer and fall. In late April or early May, place the small bulbs about an inch deep in the garden, with four bulbs together, touching each other, and each bunch of four onion sets about 6 inches apart within rows. 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