Life

The Casual Gardener: Working over winter

Onions are among the best crops for keeping your vegetable patch productive during the winter months, writes John Manley

Onions are among the best crops for overwintering
Onions are among the best crops for overwintering Onions are among the best crops for overwintering

PLANTING crops in the autumn will give them a head start on those that would otherwise be planted in the spring, sometimes up to five months later. However, this head start will be far from commensurate to the difference between autumn and spring planting times, as growth slows dramatically during winter. While ultimately the difference in harvest times will only be a matter of weeks, the advantages of overwintering vegetables go well beyond mere time.

Firstly, there’s the self-satisfaction of planting your ground when everybody else has wound down for the year. It also creates an interest in the veg patch over the winter months when normally you’d likely only have bare, damp soil to look at. Additionally, it is always a good idea to keep your ground productive, no matter what the time of year.

One of my favourite overwintering crops – alongside kale, purple-sprouting broccoli and broad beans – is onions. The name 'onion' can be applied to any plant in the genus Allium, but A. cepa is what your likely to eat with your burger or kebab. Other commonly known edible plants in the genus are garlic, leeks, and the aforementioned salad onions and shallots.

Onions can either be grown from seed or from 'sets', which are small bulbs raised the previous year from seed by a commercial grower. Sets are widely available in garden centres and are the best bet for a beginner. There is a wider variety of cultivars and taste nuances available if growing from seed, but as onions are biennial it takes at least three times as long from sowing to harvest as it does with sets. Spring onions – or scallions – are merely common garden onions harvested while immature, though it's best to select special varieties.

Onions like full sun and are most at home in sandy loam, though they'll tolerate most soils – even poorer ones. However, it's recommended you improve your ground beforehand with garden compost. The denser the planting, the smaller the onions, so bulbs should be planted shallow, four-to-six inches apart, giving the onion enough room to expand. The same rules apply to red onions and shallots. If planted closer they will still grow, though not quite as big.

If you adhere to a crop rotation regime, onions follow potatoes and other root crops.

Plant them so the tip is level with the surface of the soil and keep a close eye on them during the first few weeks as this is when they’re susceptible to being disturbed by birds. Very often the birds will merely pull up the young onion before it has taken root and discard it nearby. If this the case, simply replant it back in the original position. Also be wary of weeds and keep the ground between rows clear, as the onion's lack of broad-leafed foliage means it has no canopy to suppress weed growth.

Traditionally Japanese onions overwinter best in this part of the world though suitable European varieties have emerged in recent years. A good golden-skinned autumn planting variety is 'Shakespeare', which forms good sized bulbs that store well. For a red overwintering onion try 'Electric', which produces semi globe shaped bulbs with crisp, pink-tinged flesh.

'Senshyu' is one of the original Japanese varieties with a reliable track record. It produces good yields of semi-flat bulbs with straw yellow skins. 'Eschalote Grise' is a khaki coloured, gourmet shallot originating in Kazakhstan and becoming increasingly popular in north-west Europe.