Sowing
Sow indoors in January, in plug trays, three seeds per plug. Plant the whole clump out as one — don't thin it. Top the plants to about 6 cm.
Month by month
January: sow indoors in plug trays, three seeds per plug.
February: start feeding with a weak nutrient solution.
March: pot the whole clumps on into 7 cm pots, keep feeding, top the plants to about 6 cm.
May–June: out into the beds. Harvest-thin the clumps as the season goes.
Tips & lessons learned
Growing onion from seed is fun, and plug trays make it easy — 3 seeds per plug, leave them until late February, then move the clumps to 7 cm pots.
Methods
From sets (planted direct, April)
The lazy route: plant sets directly outside in April, tips just showing, 10–15 cm apart. Water when needed.
From the log
Grows well with
Swiss chard 
Red onion 
Turnip 
Carrot 
Parsley 
Black salsify 
Parsnip 
Petunia 
Beetroot Get the complete guide
The printable Yellow onion guide goes beyond this page — everything you need to actually grow it well, start to finish. It hasn't been made yet — it's coming as a printable PDF. Sign up for the Vegocracy newsletter below and you'll hear when it, and every other new guide, is ready.
Join the Vegocracy newsletterStep-by-step notes for every stage — sowing depth, spacing, care and what to watch for.
What to think about when picking a variety for your own garden, not just which ones earned their place in mine.
Do's and don'ts — what worked, what I'd skip next time, and the mistakes worth avoiding.
Full sow, transplant and harvest calendar for yellow onion.
The background knowledge behind the how-to — why it behaves the way it does, and what it actually needs.
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A friendly reminder: every garden plays by its own rules. Zones, soil, weather and a hundred small things decide what works — so this is how I did it and what worked for me, not a promise. Try, learn, adjust, try again.. that's half the fun anyway.
Also grows well in these combinations
Yellow onion grows best with friends
This crop is part of one of my field-tested bed recipes — complete layouts with timing for every plant in the bed.
See all bed recipes