![]() ![]() Consistent exposure to temperatures below 50☏ (10☌) for more than 10 days can cause onions to bolt rather than producing big bulbs. Harden off, but protect from chillingĮventually the onion seedlings stay outdoors 24/7, provided temperatures are well above 46☏ (8° C) at night. I shield them from wind by using my cold frame or a plastic-covered tunnel for my onion day care centre. ![]() The best light of all is found outdoors on sunny days, so my adolescent onions get moved outdoors whenever we get warm sun. Onion seedlings respond to transplanting by making strong upright growth, which I keep trimmed back to about 5 inches (12 cm) high. I snip it off and remove it to keep the containers tidy. Soon after transplanting, my onions often shed the seedling leaf (sometimes called the flag leaf). They may not be pretty, but containers made from the bottoms of milk cartons or large paper cups house the majority of my adolescent onion seedlings. In my experience, onion seedlings that are given plenty of vertical root space grow much more rapidly than those confined to shallower quarters. When an onion seedling has three leaves, I gently transplant to containers that are at least 4 inches (10 cm) deep. Every day or so I trim the onions back to about 3 inches (7-8 cm) tall, which keeps them from falling over. I keep the lights on my onions for 12 hours a day, and position them within 1 inch (2.5 cm) of the bulbs. Keep under lights and trim backĪt this point growing onions from seed requires bright supplemental light, which I provide with a two-bulb florescent fixture. To shorten this drama and encourage the seedling to get on with growing into an upright onion, I often "rescue the chick" by snipping the loop in half, pulling out the smaller end, and discarding it. Eventually the smaller end pulls out of the soil, weighted down by the black remains of the seed husk. The stuck seedling looks like a little green loop. Soon after germination occurs, my indoor-grown onion seedlings often do a poor job of pulling away from the seed. I enclose newly seeded containers in a plastic bag to maintain moisture, provide them with bottom heat, and the onion seeds germinate in about 8 days. Before I started using the top of my plant light, I found that the top of the refrigerator was a sufficiently warm place to germinate onions. Onion germination is fastest as 68-77☏ (20-25☌), with slight temperature drops at night. The tops of my fluorescent plant lights are flat, and they give off just the right amount of bottom heat needed to help onion seeds germinate quickly. My onion seedlings stay in pots for up to 10 weeks, so I like to use a soil medium that's unlikely to host diseases. I also purchase a fresh bag of seed-starting mix each spring as a safety precaution against soil-borne diseases. 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. ![]() 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. Start with fresh seed and seed starting mix I am driven to do it, which explains the evolution of these ten guidelines for growing onions from seed. Please bear in mind that I am an onion maniac, and I have no explanation for my obsession with growing onions and shallots from seed to table year after year. We left out many small details, which I've been keeping track of in recent weeks as I've been growing onions from seed myself. In the past year, both Ben Vanheems and I have written about the virtues of growing onions from seed. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |