When to Harvest Onions

The first real harvest cue is the leaves bending over at the neck of the bulb. Walk past your onion bed and look down. If the green tops are still standing straight up like chives, your onions are still bulking up underground. Once the neck softens, the leaves can't hold their weight anymore and they sag sideways.

That softened neck is the plant winding down for the season. The bulb stops swelling, sugars start moving out of the leaves, and the outer skins begin to firm up. From the day the first leaves flop, you're typically one to two weeks from lift day.

Once roughly half to two-thirds of the bed has flopped, the bulbs go through a final color change. The papery outer skin starts taking on the brown, yellow, or red tone of your variety. The tops of the bulbs sitting above the soil look glossy and dry instead of pale and green.

This is the signal for storage onions. You can absolutely harvest a few early for fresh eating - young onions are sweet and great in salads - but for bulbs that need to last through fall and winter, hold off until the skins have colored up properly.

Slide a hand fork or garden fork under each bulb and gently lever it up. Don't yank by the leaves. The pull point is the soil around the roots, not the foliage above. Once the soil loosens, the bulb lifts straight out with the roots still attached.

Keep the roots and leaves intact. They're not just for looks - they help the bulb shut down naturally during curing, which is what gives you a long storage life. Shake off the worst of the dirt, but skip any real cleaning until the cure is done.

Look at each bulb as it comes out of the ground. Anything that's tiny, split, badly damaged, or that bolted to flower goes in a separate pile. Those won't store - the open neck of a bolted onion lets air and bacteria straight into the bulb - but they'll keep for a week or two in the fridge for fresh eating.

Any bulb that already feels soft, squidgy, or smells off gets tossed entirely. One rotting onion can spoil the bulbs touching it during storage. Only firm, dry-necked, healthy-looking bulbs make it onto the cure rack.

Curing is just controlled drying. You're looking for somewhere dry, sheltered from rain, and with strong air circulation. A greenhouse with a slatted wooden rack is ideal because the warmth speeds the cure, but a porch, garage, lean-to, or covered hoop house works just as well.

What you need to avoid is damp ground, still air, and direct rain. Wet curing onions go straight to rot. Lay them on a raised slatted rack so air moves both above and below, and keep them out of bright direct sun (the bulbs can scald like a sunburn).

Spread the bulbs out so they're not piled on top of each other. A single layer on a slatted rack is best. If you're short on rack space, you can thread bulbs through wire mesh by the foliage so they hang in rows.

Leave them alone for two to four weeks. Most home gardeners need the full month, especially in cool or humid climates. The cure is done when the leaves shrivel up brown, the roots feel wiry and dry, and the outer skins have gone fully papery and seal in the bulb.

Once the skins are papery, you can clean the bulbs up for storage. Brush off loose dirt with your fingers or a soft brush. Snip the dried roots short with kitchen shears or pruning snips. Leave the papery outer skin alone - it's the moisture seal that lets the bulb keep for months.

If you're storing in nets or sacks, cut the leaves down to a short stump above the bulb. If you're braiding them into onion strings, leave at least six inches (15 cm) of foliage on so you have material to weave with. Don't nick the bulb itself when you cut.

Cured onions store in four classic ways. Mesh sacks or breathable produce bags hung from a hook are the simplest. Old panty hose with a knot tied between each bulb works (yes, really - it's a classic gardener's trick). Tying small bunches together by the leaves on a piece of string is quick. Hand-woven onion strings are the prettiest and let you pluck one bulb at a time from the bottom.

Whatever method you use, move the finished bulbs somewhere cool, dry, and dark. A basement, frost-free outbuilding, or cool spare room all work. Skip direct sun and high humidity. Check the bulbs every few weeks and use any that start softening first. Well-stored onions can last you right through to next spring.