When to Harvest Onions (US Guide)
Onions are ready when 50–75% of tops fall naturally. This US guide covers harvest timing by zone, curing methods, and storage for months after picking.
Key takeaways
- Harvest when 50–75% of the green tops have naturally fallen over — this signals bulb maturation is complete
- Do not bend tops over manually to force harvest — this damages the neck and allows rot to enter during curing
- Cure onions for 2–4 weeks in warm (80–90°F), dry, well-ventilated conditions before storing
- Long-day onions (planted in spring in Zones 3–6) bulb up in response to long summer days; short-day onions (planted in fall in Zones 7–10) bulb in response to shorter winter/spring days
- Properly cured onions store 3–6 months at 32–40°F with good air circulation; sweet varieties store only 1–2 months
Understanding when onions are ready to harvest
Onions are ready to harvest when 50–75% of the green tops have naturally fallen over — a process called lodging — and the neck (where the leaves meet the bulb) feels thin, papery, and dry. Harvesting too early produces smaller, less flavorful bulbs that rot in storage. Harvesting too late risks disease and soggy conditions in the bulb.
Most US gardeners harvest too early. The instinct is to pull onions when the bulbs look large enough, but the falling tops signal a specific biological change: the plant has completed bulb formation and redirected energy from leaf growth to bulb curing. Pulling before this stage interrupts that process.
The 50–75% rule: Once half to three-quarters of your onion tops have naturally fallen over, harvest the entire bed within 1 week — including plants whose tops are still upright. At that stage, bulbing is complete across the planting.
Long-day versus short-day onions: timing varies by US region
The most important factor in onion timing is day length — and matching onion type to your US latitude determines whether you get small golf balls or proper large bulbs.
| Onion type | Day length to bulb | Best US regions | Planting time | Harvest time |
|---|---|---|---|---|
| Long-day | 14–16 hours | Zones 3–6 (northern US) | Spring | Mid-July to August |
| Intermediate-day | 12–14 hours | Zones 5–7 (mid-US) | Spring | July |
| Short-day | 10–12 hours | Zones 7–10 (southern US) | Fall | April–June |
Long-day varieties for northern US gardens: ‘Walla Walla’ (Washington state icon; very sweet; poor storage), ‘Yellow Sweet Spanish’, ‘Patterson’, ‘Copra’ (excellent storage, 6–8 months). Seed available from Johnny’s Selected Seeds and High Mowing Seeds.
Short-day varieties for southern US: ‘Vidalia’ (Georgia; trademarked name for short-day onions grown in specific Georgia counties), ‘1015Y Texas Supersweet’ (Texas A&M release), ‘Granex’ (most commonly grown short-day type in the Southeast).
Intermediate-day varieties grow across the mid-US and provide more flexibility for gardeners in the transition zones. ‘Red Candy Apple’, ‘Candy’, and ‘Super Star’ are widely available at US garden centers in the intermediate category.
A long-day variety planted in Zone 8 Georgia will never develop a full-sized bulb — the days never get long enough to trigger bulbing. This mismatch is the most common reason home gardeners get small or disappointing onions.
When onions are ready to harvest by US zone
Zones 3–4 (northern US, Minnesota, Maine, North Dakota):
- Planting: Spring, April–May as soon as soil is workable
- Tops begin falling: Mid to late July
- Harvest: Late July to early August
- Variety type: Long-day required
Zones 5–6 (Ohio, Pennsylvania, Missouri, Kansas):
- Planting: March–April (sets or transplants)
- Tops begin falling: Late July to early August
- Harvest: August
- Variety type: Long-day or intermediate-day
Zones 7–8 (Tennessee, Arkansas, Virginia, Pacific Northwest):
- Option 1 (spring): Long-day or intermediate planted March; harvest July–August
- Option 2 (fall): Short-day planted September–October; harvest April–May
- Best storage onions: Option 1 (spring planting, long-day)
Zones 9–10 (southern Texas, Florida, southern California):
- Planting: October–December
- Harvest: March–May
- Variety type: Short-day required
For companion vegetables that coordinate well with onion timing in the vegetable garden, see What to Plant with Onions (US Guide) and Companion Planting Chart.
Signs that onions are ready — and signs they’re not
Ready to harvest:
- 50–75% of tops have naturally fallen over (not artificially bent)
- Fallen tops are yellowing or browning
- Neck feels thin and papery when gently squeezed
- Outer skin on bulb is papery and dry, not green or tight
- Plant no longer feels like it’s actively growing
Not ready:
- Most tops still green and upright
- Neck feels thick and succulent when squeezed
- Skin is tight against the bulb, not papery
- New green growth visible from the center of the plant
Past ready (overdue):
- Tops completely dead and dry
- Bulbs have pushed partially out of the soil
- Double-nose or split bulbs developing (a sign of bolting or stress during growth)
- Soft spots developing at the neck
If an onion has bolted (sent up a flower stalk), harvest it immediately — bolted onions do not store. Use them fresh within a few days.
How to harvest onions
Choose a dry day for harvest. Wet conditions during harvest increase rot risk during curing.
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Stop watering 1–2 weeks before harvest. Dry conditions harden off bulbs, tighten necks, and improve storage quality. This is especially important for storage varieties.
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Loosen soil before pulling. Use a garden fork to loosen soil 3–4 inches from the bulb. This prevents breaking roots and tearing the neck.
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Pull bulbs gently. Grip at the base of the neck (not the leaves) and pull upward with a gentle twisting motion.
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Do not knock bulbs together to remove soil. Bruising creates entry points for rot. Gently brush off loose soil.
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Leave tops attached. Do not cut tops until after curing is complete.
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Move to curing location immediately. Do not leave harvested bulbs in the sun for extended periods — sunscald reduces storage quality.
Curing onions: the step most US gardeners skip
Curing is the process of drying the outer layers of the onion into a tight, papery skin that protects the interior during storage. It takes 2–4 weeks and is the single most important step for long-term storage onions. Uncured storage onions will rot within 1–2 months regardless of storage conditions.
Curing conditions:
- Temperature: 75–90°F
- Humidity: Low — below 60% if possible
- Airflow: Good air circulation around all bulbs
- Light: Diffuse indirect light or shade — full sun dries the neck too fast and can sunscald skin
Curing methods:
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Screen or mesh trays: Spread onions in a single layer on wire mesh or window screen raised off the ground for air circulation. Best for small quantities.
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Braid or tie and hang: Traditional method — braid leaves together or tie with twine and hang bunches of 10–15 in an airy, dry space (garage, covered porch, shed). The roots face outward so roots dry while the bulb hangs. Good for any quantity.
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Barn or shed floor: Spread in single layers on newspaper or clean cardboard. Turn every 3–4 days for even drying. Works but requires more active management.
In humid US climates (Southeast, Gulf Coast): Curing is more challenging in Zones 7–10 where summer humidity is high. Use a fan to ensure continuous air movement. A covered porch or garage with a box fan running continuously works well.
Curing is complete when:
- Outer skins are completely dry and papery
- Neck is fully dry and sealed (twist the neck — it should feel dry and papery, not give or flex)
- Roots are fully dry and shriveled
- When tapping two bulbs together, they make a hollow sound
Trim roots to 1/2 inch after curing. Cut tops 1–2 inches above the neck.
Storing cured onions
Properly cured storage onions keep for 3–8 months depending on variety:
| Variety type | Storage life | Notes |
|---|---|---|
| Sweet varieties (‘Walla Walla’, ‘Vidalia’, ‘1015Y’) | 1–2 months | High water content; eat fresh or refrigerate |
| Standard yellow storage (‘Copra’, ‘Patterson’, ‘Stuttgarter’) | 4–6 months | Best storage life; dry, dense flesh |
| Red varieties | 2–4 months | Shorter storage than yellow; use in first half of winter |
| White varieties | 2–4 months | Similar to red; milder flavor |
Storage conditions:
- Temperature: 32–40°F (refrigerator temperature)
- Humidity: Low — dry conditions prevent rot
- Air circulation: Mesh bags, open crates, or slatted boxes — never sealed plastic bags
- Light: Dark or dim conditions prevent sprouting
In most US climates, a cool basement, unheated garage (above freezing), or root cellar meets these requirements from October through March. South of Zone 7, where winters are mild, refrigerator storage in mesh bags is the most practical option.
Do not store onions with apples or potatoes. Apples emit ethylene gas that speeds sprouting in onions. Onions release moisture that can cause potatoes to rot.
Harvesting green onions and scallions
Green onions (scallions) are different from storage onions — they are harvested before the bulb develops, when the tops are young and green.
Harvest scallions:
- At any size when tops are 6–8 inches tall and the base is ½ inch or more in diameter
- Pull entire plant or cut leaves to soil level (cut leaves regrow for additional harvests)
- No curing needed — use immediately or refrigerate for up to 1 week
For garlic timing comparison — another allium with similar but distinct harvest cues — see When to Harvest Garlic (US Guide). For beet harvest timing that overlaps with onion season in many US gardens, How to Grow Beets covers the mid-summer harvest window in detail.
Onion harvest by US state: zone-specific timing
| State | Planting | Variety type | Expected harvest |
|---|---|---|---|
| Minnesota, Wisconsin, Maine | April–May | Long-day | Late July–August |
| Ohio, Pennsylvania, Illinois | March–April | Long-day | July–August |
| Missouri, Kansas, Virginia | March–April | Long-day or intermediate | July–August |
| Tennessee, Arkansas | March (long-day) or Sept–Oct (short-day) | Both | July or April–May |
| Georgia, Alabama | October–November | Short-day | April–May |
| Texas | October–December | Short-day | March–May |
| California (Central Valley) | October–January | Short-day | April–June |
| California (Northern) | February–March | Long-day or intermediate | June–July |
| Pacific Northwest (Oregon, Washington) | March–April | Long-day | July–August |
Walla Walla onions (Washington and Oregon) are a regional specialty — a long-day sweet variety so mild they’re eaten raw like apples. Available from regional seed companies like Territorial Seed. Plant February–March; harvest July. They store poorly (2–4 weeks) but taste exceptional fresh.
Troubleshooting onion harvest problems
| Problem | Likely cause | What to do |
|---|---|---|
| Bulbs are small | Day-length mismatch, late planting, too-close spacing | Next year: correct variety type, plant earlier, space 4–6 inches |
| Tops haven’t fallen by August (Zones 5–6) | May be a late variety, cool summer, or late planting | Wait up to 2 more weeks; if frost approaches, harvest anyway |
| Thick, wet necks | Harvested too early | Use immediately; these won’t cure well |
| Rot during curing | High humidity, poor airflow, or bruised bulbs during harvest | Improve airflow; sort and remove any already-soft bulbs; use damaged ones immediately |
| Bolting (flower stalk) | Temperature stress, day-length disruption | Harvest immediately; bolted onions don’t store |
| Double nose (two bulbs fused) | Temperature or day-length disruption during growth | Harvest and use fresh; double-nose onions store poorly |
Sarah Mitchell is a Master Gardener and garden writer based in the Pacific Northwest. She has been growing food and flowers for over 15 years across USDA zones 7 and 8.