Walla Onion Seeds

Start Walla Walla Onion seeds indoors 8–10 weeks before your last expected frost, or direct-sow outdoors as soon as soil can be worked in spring — onions tolerate cold soil better than most vegetables. Sow seeds ¼ inch deep in loose, well-draining mix; press lightly and keep evenly moist. Germination happens in 7–10 days at 65–75°F. Once sprouts hit about 3 inches tall indoors, trim the tops back to 2 inches to encourage thicker stems before transplanting. When moving outdoors, space plants 3–6 inches apart to avoid crowding.

Onion Walla Walla is a long-day plant and it needs every hour of light, especially as bulbing season approaches. Soil should be loose and sandy-loamy. Don’t use compacted ground, as it is hard for onion bulbs to expand to its 3–6 inch potential. Work in compost or aged manure before planting. Water consistently but not aggressively — about an inch per week, and a little more in heat. Once you see the tops starting to lean and yellow naturally, back off watering entirely. That signals the bulb is maturing and excess moisture at that stage causes rot.

Thin early and don't feel bad about it — pulled thinnings make excellent green onions, so nothing goes to waste. Feed with a nitrogen-rich fertilizer every 3–4 weeks through midsummer, then switch to a low-nitrogen formula once bulbs start to swell. Onion Walla Walla plants have shallow roots, so hand-weed carefully rather than hoeing aggressively near the base. When about half the tops have fallen over naturally, bend the rest down by hand and let the bulbs cure in the ground for a few more days before pulling. Cure harvested bulbs in a warm, dry, well-ventilated spot for 2–3 weeks before storing.