How do I know when onions are ready to harvest?
Written by
Liu Xiaohui
Reviewed by
Prof. Charles Hartman, Ph.D.Identifying onion harvest readiness minimizes waste. Harvest too early and your onions will remain small. Wait too long and they'll rot. I provide gardeners with these five unmistakable signals every year. Your onions also have obvious visual signals.
Top Collapse Percentage
- 80-90% of green tops must brown and collapse naturally. This signals finished energy transfer to bulbs. I count fallen tops daily near harvest season.
Neck Softness Test
- Squeeze where leaves meet bulbs. Soft necks mean carbohydrates moved completely into bulbs. Hard necks need more growth time. I check this morning and evening.
Skin Rustle Sound
- Papery outer skins rustle like dried leaves when touched. Protective layers form only at full maturity. Listen for this crisp sound during inspections.
Expectations for bulb sizes vary depending on the type of bulb. Sweet onions have target sizes of 3-4 inches in width, while storage varieties have target sizes of 4-5 inches. I refer to seed packets to see what size I am targeting. The size is much more important than the calendar dates when determining when to harvest.
The youngest leaf nearest the bulb base should feel entirely dry. Green in this area allows for storage rot. I once lost onions by failing to heed this warning. Now I peel layers back to check for drying before harvesting.
Papery skins prevent the plant fruit from moisture injury. When the fruit is ready, they slide off easily, exposing the dry layers. You can test this by gently rubbing the skin. If the skins are not completely removed, you will have to stay in the field longer. This barrier forms last before harvest.
Read the full article: 7 Essential Signs for When to Harvest Onions
