Growing onions is rewarding, but knowing when to harvest onion can be tricky for beginners. Harvesting at the right time ensures your onions are full of flavor, store well, and last longer. In this guide, you’ll learn how to know when onions are ready to harvest, signs to watch for, the best harvesting practices, and what happens if you harvest too early or too late. If you’re growing other bulb crops, check out when garlic is ready to harvest and when to harvest canna rhizomes.
How to Know When Onions Are Ready to Harvest
Onions give clear signs when they’re mature. Here’s how to tell:
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Falling tops: When the green onion leaves (tops) bend over and turn yellow or brown, it means the bulb has stopped growing.
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Bulb size: Mature bulb onions are usually visible above the soil and feel firm when squeezed.
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Neck softening: A ready-to-harvest onion will have a thin, soft neck that bends easily.
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Days to maturity: Depending on the variety, onions usually take 100–120 days from planting to harvest.
For red onions, yellow onions, and white onions, these signs remain the same.
For green onions or spring onions, you can harvest earlier when the shoots are pencil-thick.
When Not to Harvest Onion
Avoid harvesting if:
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The tops are still green and upright (the bulbs are still growing).
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The neck is thick and stiff.
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The bulb feels soft or mushy (not mature yet).
Pulling onions too early can lead to small, weak bulbs that don’t store well.
Maturity Days for Onions
Here are the key maturity points to know when onions are ready for harvest:
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Tops have fallen over (80–90% of plants).
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Bulbs are round, full, and firm.
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Outer skins are papery and dry.
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Neck tissue is thin and soft.
| Onion Variety | Bulb Color at Maturity | Days to Maturity | Best Harvest Season |
|---|---|---|---|
| Yellow Onion (Common Storage) | Golden Yellow | 100–120 days | Late Summer – Fall |
| Red Onion | Deep Red / Purple | 100–110 days | Late Summer – Fall |
| White Onion | Bright White | 100–120 days | Late Summer – Fall |
| Sweet Onion (e.g., Vidalia, Walla Walla) | Pale Yellow to White | 90–100 days | Summer – Early Fall |
| Spring Onion (Green Onion) | Green Tops, Small Bulb | 30–60 days | Spring – Early Summer |
| Shallots (Close Relative) | Copper to Red-Brown | 90–120 days | Summer – Fall |
| Bunching Onion (Scallions) | Green Tops, No Bulb | 60–80 days | Spring – Early Summer |
| Cipollini Onion (Flat Onion) | Yellow or Red Flat Bulb | 90–100 days | Late Summer – Fall |
| Egyptian Walking Onion | Small Reddish Bulbs | 90–120 days | Summer – Fall |
| Pearl Onion (Miniature) | White or Yellow | 60–90 days | Summer – Early Fall |
Best Time of Day to Harvest Onions
The best time is on a dry, sunny morning. Harvesting onions in dry weather helps prevent rot and allows bulbs to cure faster. Avoid harvesting right after rain or watering, as wet bulbs are harder to store.
How to Harvest Onions Properly
Follow these steps for a perfect onion harvest:
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Loosen the soil around the bulb with a garden fork.
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Gently pull the onions from the base, avoiding damage.
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Lay them out in a single layer on the ground (if sunny and dry) or in a well-ventilated shed.
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Cure them for 2–3 weeks until the skins are dry and papery.
What Happens if You Harvest Onions Too Early or Too Late?
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Too Early: Small bulbs, poor flavor, shorter storage life.
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Too Late: Bulbs may split, sprout, or rot in the soil.
For green onions, harvesting early is fine since they’re eaten fresh. But for bulb onions, timing is crucial.
How Often to Harvest Onions
Onions don’t ripen all at once. You may need to harvest in stages:
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Green onions: Harvest as soon as shoots are 6–8 inches tall.
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Bulb onions: Harvest when most of the tops have fallen over.
Check your crop every few days once the first tops begin to fall.
Storage Tips After Harvest
Proper storage keeps onions fresh for months:
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Cure first: Dry for 2–3 weeks until skins are papery.
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Trim tops and roots: Leave 1 inch of neck.
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Store in mesh bags or crates: Keep in a cool, dry, dark place (32–40°F / 0–4°C).
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Avoid plastic bags: They trap moisture and cause rot.
Yellow onions store the longest, while sweet onions and red onions have a shorter shelf life.
Best Practices for Sweeter, Tastier Onions
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Plant onions in loose, well-drained soil with full sun.
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Water consistently, but reduce watering 2 weeks before harvest.
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Harvest on dry days to lock in sweetness.
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For Walla Walla onions and other sweet varieties, eat fresh as they don’t store long.
FAQs About Onion Harvesting
1. When are onions ready to harvest?
When 80–90% of the tops fall over and bulbs are firm.
2. How do I know when red onions are ready to harvest?
The same signs as yellow onions tops fall over, necks soften, and skins dry.
3. When to harvest onions planted in spring or fall?
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Spring-planted onions: Late summer to early fall.
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Fall-planted onions: Early summer the following year.
4. When to harvest green onions?
As soon as the shoots reach 6 12 inches tall, usually 30–60 days after planting.
5. Can I harvest onions after they flower?
If onions flower, bulbs won’t store well. Use them fresh.
Final Words
Knowing when to harvest onion is the key to bigger bulbs, better taste, and longer storage. Watch for falling tops, soft necks, and papery skins. Avoid harvesting too early or too late, and always cure your onions properly for storage. Whether you’re growing green onions, red onions, yellow onions, or sweet onions, the right harvest time makes all the difference.
