I’d not heard of this before and am so looking forward to trying it. Here is a link to Territorial Seed Co who tells of this: https://youtu.be/0skgSP57Fyk?si=y_i8dnAXqWy7qvWj
A simple guide using onion starts
Overwintering onions means planting bulbing onion starts in fall, letting them sit quietly through winter, and harvesting big, early onions the following spring. I’ve read this method works beautifully in my climate — cold enough to trigger bulbing, but warm enough that the soil doesn’t freeze solid.
Starting with onion starts makes the process easy and reliable.
🍂 Why Overwinter Onions? • Bigger bulbs — fall planting gives onions a head start • Earlier harvest — May–June instead of July–August • Less watering — winter does the work • Less weed pressure — onions are already established by spring • Better bed efficiency — frees up spring planting space
📅 When to Plant (41°N, Zone 8b) Plant onion starts between October 1–20.
This gives them: • time to root before hard frost • enough cold exposure to trigger bulbing in spring
Starts are ideal because they establish quickly.
🌱 What to Plant (Long Day Onion Starts) Choose long day bulbing onions — these bulb correctly at my latitude.
Great overwintering varieties: • Walla Walla • Yellow Sweet Spanish • Copra • Redwing • Patterson • Ailsa Craig (huge bulbs)
Avoid short day onions — they won’t bulb properly this far north.
🛏️ How to Plant Onion Starts
- Prepare the bed • Loosen soil 6–8 inches • Add compost (No fertilizer needed — overwintered onions don’t want fall nitrogen.)
- Square‑Foot Spacing • Plant 9 onions per square foot • 3 × 3 grid • Each start 4 inches apart • Bury them just deep enough to cover the white part of the stem
- Mulch lightly • 1 inch of straw or leaves • Enough to buffer cold, not enough to smother
- Water once • Just to settle the soil • After that, winter rain handles everything
❄️ What Happens in Winter • Tops may die back or stay small — both are normal • Roots stay alive • Plants sit quietly until daylight increases • No watering needed • No fertilizing needed
This is the easiest part.
🌞 Spring Growth (March–May) As daylight increases: • onions begin rapid leaf growth • bulbs start swelling • you can side dress with compost if needed • keep them watered during bulbing
Overwintered onions often outgrow spring planted onions by a mile.
🧅 Harvest (May–June) You’ll know they’re ready when: • tops fall over • necks soften • bulbs feel firm and full
Pull them, cure them for 1–2 weeks, and store.
Overwintered onions often store better because they mature earlier in cooler weather.
🌻 Tips for Success • Don’t over‑mulch — onions don’t like being buried • Protect from deer (they love onion tops) • Avoid nitrogen in fall — encourages too much leafy growth • Choose long day varieties only • Don’t worry if tops look sad in winter — that’s normal
🏡 Why This Works So Well Here Klamath River winters: • can dip into the teens on occasion, but not normal these days • bounce back • don’t freeze soil solid • warm early in spring
This is perfect overwintering onion weather.
Overwintering onions is one of the easiest ways to get bigger bulbs, earlier harvests, and a more efficient homestead garden. Starting with onion starts makes the process simple, reliable, and beginner friendly. (or so I have read)
🧅 The simple version of “why and how” Onions bulb based on day length, not temperature. Overwintering onions simply gives them a head start so they have more leaf growth by the time long spring days trigger bulbing.
That’s the whole secret.
🌻 Why this works at my latitude (41°N) I live in a long day onion zone, which is perfect for overwintering: • Fall planting lets onions establish • Winter keeps them dormant but alive • Spring gives them time to grow leaves • Long days in late spring trigger bulbing • I harvest in May–June instead of July–August
It’s a natural fit. And I can’t wait to try this!
