When to Harvest Onions and How to Cure and Store Them

What eighty per cent down actually means

When a bulb has finished filling, the tissue at the base of the leaves softens and the top falls under its own weight. The tops going over is the plant telling you from the inside that bulbing has finished. Look across the whole bed, and when roughly eighty per cent are down, that is your moment.

Lift too early and the bulbs are not only small: the neck is still thick and full of water, so it will not dry and it rots in store. Leave them too long after they fall and the outer skin deteriorates in the soil and water gets in at the base. About a week to ten days after they go over is the point to stop.

1. Count the rows Run your eye down each row and estimate whether eighty per cent are over. Plants that went down early may be diseased, so leave those out of the count.
2. Feel the neck The base of the leaves should be soft when you pinch it. Still hard and thick means that plant is not ready.
3. Do not count storm damage Plants flattened by heavy rain or wind have not finished bulbing. See whether they stand up again the next day, and if they do, do not count them.

A few plants going over well before the rest is usually disease or root damage rather than maturity. Judge on the whole bed and handle the early ones separately.

Choosing the day

In some years the right harvest window and the start of the wet season overlap. Look at the forecast a week out and secure the drying window first.

1. Two or three dry days ahead Pick a day where the forecast stays dry through the drying period as well. Rain straight after lifting stalls the drying and costs you storage life.
2. Not immediately after rain Wet soil sticks to the bulbs and slows the drying. If it rained yesterday, wait a day or two for the surface to dry.
3. Work in the morning Lift in the morning and lay them out so the day's sun and wind dry the surface. Lifted in the evening they spend a damp night wet.
4. Cut your losses if wet weather is coming Even at sixty or seventy per cent down, if a wet spell is closing in it is better to lift and dry. In a year you cannot cure, storage beats size.

Drying in the field

Lay the lifted bulbs on the surface of the bed with the tops of one row covering the bulbs of the next, so the leaves shade the bulbs from direct sun. Two or three days like that dries the outer skin and the surface soil falls away.

Bulbs left in strong sun with no cover scald, which shows later as soft brown patches under the skin. Shading them with their own leaves is the simplest protection there is.

1. Lay them in the same direction Set the rows so the leaves of one cover the bulbs of the next. It takes no extra time and prevents scald.
2. Two or three days Until the outer skin rustles and the soil brushes off dry. Bring them under cover if rain arrives.
3. Do not wash them Rub dry soil off with your hands. Washing damages the skin and shortens storage considerably.

Curing and hanging

After the field drying, hang them somewhere airy and out of the rain for two to three weeks. This is curing, and it is what closes the neck and dries the outer scales into a papery skin. Skip it and bulbs that looked perfect start to soften within weeks.

Plait the leaves together or tie them in bunches and hang them under an overhang or in an open shed. What matters is moving air rather than warmth. Piled in a crate they sweat in the middle and rot from there.

The neck is the test. Pinch it after curing: it should be thin and dry. Anything still thick and soft will not keep, so use those first.

Sorting and storing

Sort as you take them down from curing. Bulbs with thick open necks, split bulbs, any that were damaged when you lifted them, and any that feel soft go in a separate pile to eat first. One rotting onion spoils everything around it.

Store the rest somewhere cool, dark and airy. Net bags, plaits hung up, or slatted crates all work. A sealed container or a plastic bag traps moisture and they rot.

1. Check the neck on every bulb Thin and dry goes into store. Thick, soft or still green goes into the eat-first pile whatever its size.
2. Set damaged bulbs aside Anything nicked by a fork, split, or scalded will not keep. Use them within a few weeks.
3. Check the store monthly Go through the bags once a month and take out anything softening. Catching one early saves the rest.

Early varieties are meant to be eaten, not stored. Plan to use them through summer and rely on mid and late maincrop for the winter.