Harvest guide

Onion harvest guide: when to pick and how much to expect

Onions tell you when they're ready: the leaves yellow and flop over. Lift them at the right time and dry them well, and they can keep until next spring.

Days to harvest: 100 days from planting(Montana State University Extension)
Harvest months: June–September(RHS)
Typical yield: 4.5 kg per 3 m row (10 lb per 10 ft)(Montana State University Extension)
Spacing: 10 cm (4 in) apart, rows 25–30 cm (10–12 in) apart(RHS)
Family: Amaryllidaceae (onion family)
Botanical name: Allium cepa

Onion planting and harvest calendar

Sow January–April, August–September. Plant out March–April, September–November. Harvest June–September.(RHS)

Onion season timeline

Sow
Plant out
Harvest

Months are for a temperate Northern Hemisphere climate, based on RHS (UK) guidance. Shift them earlier or later to match your own frost dates, or by about six months in the Southern Hemisphere.

Sow
Plant out
Harvest

When to harvest onions

Yellowing leaves that topple over show the bulbs are maturing. Lift them before the foliage has died right back.(RHS)
Onions are ready to store when the necks are tight and the outer skins dry.(University of Minnesota Extension)
Bending the tops over by hand is no longer recommended. Let them fall naturally.(RHS)

How often to pick

Onions are harvested in one go. Autumn-planted sets are usually ready in June and July, and spring-planted or seed-grown onions from July to October.(RHS)

Bulb onions from transplants or sets.(Montana State University Extension)

How many onions to expect

A 3 m (10 ft) row typically gives about 4.5 kg (10 lb).(Montana State University Extension)

Yields vary with variety, weather, soil and care. Treat these as ballpark figures, not targets.

Plan for your family

For 4 people eating onions fresh, plan on about 30–61 m (100–200 ft) of row(University of Missouri Extension). That should give roughly 45–91 kg (100–200 lb)(Montana State University Extension).

Dry bulb onions.

See the full planting-per-person guide →

Storing your onions

Dry the bulbs for about two weeks somewhere sunny and airy, on racks if possible, until the skins and leaves are papery.(RHS)
Store them cool and dry. University of Minnesota Extension gives about four months as a typical shelf life.(University of Minnesota Extension)
Keep them somewhere light and well ventilated, in nets or single-layer trays, and use any bruised bulbs first.(RHS)

Track it

Log every onion harvest

Harvest Journal is a private garden journal for your phone. Tap to log each picking of onions by weight or count, and see your season add up, with no account needed.

Prefer paper? Make a free harvest report PDF in your browser, with no account needed.

Onion harvest FAQ

When are onions ready to harvest?

When most of the leaves have yellowed and fallen over, but before they have died back completely. Lift gently with a fork to avoid bruising.

How do I dry onions for storage?

Lay them out in the sun or in an airy shed for about two weeks until the skins are papery. The RHS then suggests storing them in nets or trays somewhere cool, dry, light and well ventilated.