How to Harvest Onions: When and How

A Professional Gardener's Guide to Onion Harvesting

July 07, 2024 | 8 min read
Freshly harvested onions in a garden in Staffordshire

As a professional gardener based in Staffordshire, I've spent over 15 years cultivating all sorts of vegetables, including onions. Onions are a staple in our British kitchens, and knowing the right time and method to harvest them is crucial for both flavour and storage longevity.

Quick Answer

Harvest onions when their tops turn yellow and fall over. Pull them up gently and let them cure in a dry, warm place for a few weeks.

Recognising When Onions Are Ready

The first step in harvesting onions is to know when they're ready. In the UK, onions are generally ready for harvest between late summer and early autumn. Typically, you'll see the tops turn yellow and fall over when the onions are mature.

Visual Cues

Look for the following signs:

  • Tops turning yellow and wilting
  • Necks starting to soften
  • Bulbs pushing through the soil

How to Harvest Onions

Once you've determined that your onions are ready, it's time to harvest. The process is straightforward but requires a gentle touch to avoid damaging the bulbs.

Step-by-Step Guide

Follow these steps:

  • Wait until a dry day to avoid excess moisture, which can lead to rot.
  • Loosen the soil around the bulbs with a garden fork, being careful not to pierce them.
  • Gently pull the onions out of the soil by hand.

Curing and Storing Onions

After harvesting, curing is essential to ensure your onions last through the winter months. Curing allows the outer layers to dry and form a protective barrier against decay.

Stage Action Duration
Curing Lay onions in a single layer in a dry, airy place 2-3 weeks
Storing Keep in a cool, dark, and dry place Up to 6 months

Tips for Successful Curing

Ensure the following for effective curing:

  • Place onions in a well-ventilated area, like a shed or garage.
  • Avoid direct sunlight, which can cause the onions to sunburn.
  • Turn them occasionally to ensure even drying.

Frequently Asked Questions

How do I know if my onions are overripe?

If the bulbs start to split or the tops are completely dry and brittle, they may be overripe. It's best to harvest before this point.

Can I harvest onions too early?

Yes, harvesting onions too early can result in smaller bulbs and reduced storage life. Ensure the tops have fallen over before harvesting.

What should I do if my onions are small?

Small onions can still be delicious. Use them fresh in salads or cook them whole. Ensure proper spacing next season to encourage larger growth.

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