Growing Onions From Transplants
information from WeeBee Farms
Choosing the right site:
Onions love to grow in full sun in light, well-drained soil that's high in organic matter.
When to plant- to get to optimal size onion transplants should be planted 2-4 weeks before last frost. Aim for April 17th thru May 8th in Boulder. They must be hardened off well to withstand some frost and snow. WeeBee Farms only sells plants that are hardened off and ready to plant.
How To Plant- For big onions, plant 2-3 inches apart by pressing into soil, slightly deeper than the top of the white part, the pulling up a bit to straighten the roots. For bunching onions, remove pot and plant the block as is, or separate into two or three sections.
Caring For Onions- Onions have shallow roots and need to be watered often. They need plenty of fertilizer up until about mid-July. We like "Age-Old Organics" brand of liquid fertilizer. 5-10-5 or something similar is suggested.
Weeding onions is very important as they lose size quickly if forced to compete with weeds. If bulbs push out of the ground, mulch with straw.
Harvesting- When 50% of the tops have fallen over, push the rest over and wait 1-2 weeks for the tops to dry out. Dig up and dry out in the shade for a couple of days with the tops still on.
Storage- Choose only the long-storing varieties to store. Keep in a very cool an dry place in mesh bags. 33- 45 degrees is ideal.
Copra- a long-storing sweet yellow onion for sauteeing, soups and all types of uses
Red Cipollini- An Italian Heirloom variety that is very sweet and tasty used fresh, or for roasting and kebabs. Medium-storing.
Italian Red Bunching Onion- beautiful Italian heirloom with strong onion flavor. Pick young for milder taste, or later for bigger onions and stronger flavor. Refrigerate after picking with green tops on.
Walla Walla Sweet- Very mild and tasty sweet onion. Not for long storage.
Candy- Huge yellow onion that tastes sharp and sweet. Long-storing.
Leeks: Planting- Similar to onions but plant in 5” furrow, deeper than it was in pot. As they grow, fill furrow with soil. Harvest some in Spring, some later.