Sowing Onions

I came across an NYT article on growing onions from seeds by Margaret Roach, and it inspired me to try growing onions myself. My mother has been growing many onions and hanging them in front of her balcony. Although I’ve attempted to grow onions before, I never put much effort into researching the proper methods. I usually used onion sets from a big-box home center, but they never worked out well.

After reading the article, I realized it’s better to start with seeds. This way, I can cultivate stronger onion seedlings that are better adapted to my climate and setup. I already had some onion seeds in my seed box, so this past weekend, I planted a variety of onions and leeks:

• Red Long of Florence Onion (2023 seed, meaning the seed was collected in 2022)
• New York Early
• Cippola Borettana
• Sisikyu Sweet: a re-selection of the famous Walla Walla sweet onion
• Newberg: I obtained this seed in 2022 and was concerned about the germination rate
• King Richard Leek

For the seeds from the 2023 cycle, I decided to sow multiple seeds per cell, as onion seeds are known to have lower germination rates as they age. Each cell now has several onion seeds, and I plan to sow several onion seedlings in a single pod. As they mature, I can harvest some as spring onions. I’m excited to see how my onion seed adventure turns out.

I took some soil from our composter and garden beds—I have no issue using my garden bed or ground soil around our composter—and never felt I needed to use seedling mix. One thing I noticed, though, is that sometimes if my compost is not fully finished, it can smell. I used the makeshift compost sifter above to remove large chunks of soil or woody materials so that only fine particles will make it to the seedling tray.

Onion seeds are tiny, and I realized I should probably have made the growing medium more moist, then pack it, add the seed, and finally add a bit of soil or sand on top as weight. Because onion seeds are so small and light, careless watering may move seeds across cells. Something to remember for next time.

Based on my prior experience with a heat mat, I should expect the seeds to wake up in 3 to 4 days, and I should be able to see onion seedlings. I will grow them in a tent for several weeks, probably 6 weeks or so. Then I can harden off the seedlings each day.