Onion (Walla Walla Sweet)

Spacing

3 in(16 / sqft)

Trellis

no

Seed indoor

Feb 4(-10 w)

Transplant

Mar 18(-4 w)

Harvest

~18–22 weeks from sowing

Water

weekly

Seed shelf life

1–2 y

Lifecycle

annual

Seed source

Johnny's Selected Seeds

Shallow-rooted — keep watered through bulbing. Tops fall over when bulbs are mature; cure in a ventilated shaded space for ~2 weeks before storage. Onion seed loses viability quickly; buy fresh each year.