Onions

tray of harvested onions
tray of harvested onions

Introduction

The humble onion is one of my favourite vegetables to grow. I do not think it is possible to have too many onions, as they feature in so many recipes and they are easy to store through winter.

Onions are great, almost essential, ingredients for a wide range of sauces. I also think they go splendidly in summer salads, especially when accompanying tomatoes.

Planting

  • Planting depth: onion tip just below surface
  • Planting spacing: 10 cm between onions, 30 cm between rows

Harvesting

  • Pick with a few inches of stalk left above the bulb
  • Dry in the sun, then store in a dry cool environment
Sow
(inside)
Sow
(outside)
Harvest
(fresh)
Harvest
(stored)
January
February
March
April
May
June
July
August
September
October
November
December
= jar, = freeze, = store

Varieties

There are many varieties of onion, and they can be classified by colour, shape, culinary use, and storage properties. I like to grow red varieties to eat raw in salads, and select other onion varieties with a good reputation for storing well to use in cooking during the winter months.

Buying onion seed offers the widest choice of varieties, but seeds can be hard to germinate. Many gardeners opt to grow from onion sets instead. Onion sets are immature onions, often heat treated to prevent them bolting to flower.

Onions mature in mid-summer. It is possible to overwinter onions by planting in the autumn, and doing so will result in an earlier crop. I have had mixed results with this method. It is possible to choose varieties that tolerate cold weather and mature faster if an early crop is desired.

Spring onions are even easier to grow than standard onions, with varieties maturing in 8 to 12 weeks.

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Growing

If growing from seed, it is best to use fresh seed each year to improve germination rates. Germinating onion seed in an electric propagator can work effectively.

However, my preferred way of growing onions is to plant onion sets. These are miniature onions that are simply pushed into the prepared ground at planting time, leaving their tip just poking through the surface.

Cover freshly planted onion sets with a net. Birds will not eat the sets, but they do have an annoying habit of pulling them up. I assume they do this to check what they are, and to see if they are edible.

Apart from needing to hoe in between onions to keep weeds under control, onions are one of the easiest vegetables on the allotment to care for. After the sets have germinated, any protective nets can be removed as the birds will no longer be a problem.

Onions do not require constant watering. Some people even say that too much watering can spoil their flavour. In normal summer weather, I will leave them to grow naturally. In prolonged absence of summer rain showers, I may give them a good soaking to tide them over (once a week). In extreme hot weather they may need watering every 3 or 4 days.

When onion leaves start to turn yellow and fall over they are ready for picking.

To store onions, they need to dry out first. After picking, they can be left on top of the soil for a day or two if the weather is hot. Alternatively, spread the onions out on a large table or shelf for a few days. At first, they will release a strong onion smell, and this will naturally reduce when the onions are dry and ready for storage.

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