Choose an open, sunny site with good drainage which has preferably been dug and manured in the previous autumn. Do not plant or sow on freshly manured bed. Lime if the soil is acid. Avoid planting in an area where the previous crop was of the onion family. Many exhibitors grow their show onions in a permanent bed in order to build up fertility, but in the kitchen plot it is a much better idea to change the site annually.
Apply a general fertilizer if needed and rake the surface when the soil is reasonably dry. Tread over the area and then rake again to produce a fine, even tilth.
Sow in autumn or late winter to spring. Seeds can be sown direct in autumn to be harvested in 46 weeks to produce large bulbs (not advisable in very cold areas). Otherwise sow in August under cloches or direct September to October and harvest in 22 weeks. In cold areas and for exhibition bulbs sow under glass in July, harden off in September and transplant outdoors in November.
Sowing: Sow very thinly in 1.2cm (½ inch) deep drills, leaving about 25 to 30 cm (10 to 12 inches) between rows. Water very gently if the soil is dry, and cover with soil. When large enough to handle, thin the crop in two stages. Close spacing will give smaller onions than wider spacings. Lift the seedlings carefully – the soil should be moist and all thinnings removed to deter onion fly. (They may be used as spring onions).
Thin Spring-sown seedlings first to 2.5cm (1 inch) then when the seedlings have straightened up to 5 to 10 cm (2 to 4 inches) apart. Thin Autumn sown onion seedlings to about 2.5cm (1 inch) in the autumn. Further thin to about 5 to 10 cm (2 to 4 inches) between plants in the Spring. Seedlings raised under glass should be transplanted 4in (10cm) apart, leaving 9in (23cm) between the rows. The roots must fall vertically in the planting hole and the bulb base should be about 1/2 in (1cm) below the surface. Plant firmly.
Aftercare: Hoe carefully or weed by hand – dense weed growth will seriously affect yield. Water if the weather is dry (not otherwise) and feed occasionally. Feed an autumn-sown crop in September. Mulching is useful for cutting down the need for water and for suppressing weeds. Break off any flower stems which appear. Stop watering once the onions have swollen and pull back the covering earth or mulch to expose the bulb surface to the sun.
Harvesting: When the bulb is mature the foliage turns yellow and topples over. (Some gardeners bend over the tops as the leaves start to yellow). Leave them for about 2 weeks and then carefully lift with a fork on a dry day.
Storing: Inspect the bulbs carefully – all damaged, soft, spotted and thick-necked onions should be set aside for kitchen use or freezing. The rest can be stored. The onions which are not for immediate use must be thoroughly dried. Spread out the bulbs on sacking or in trays – outdoors if the weather is warm and sunny. Drying will take 7 to 21 days, depending on the size of the bulbs and the air temperature. Store in trays, net bags, tights or tie to a length of cord as onion ropes. Choose a cool and well-lit place; they will keep until late spring.
Why grow from seed?
Most onions may be grown from seed or from 'sets'. Sets are produced by sowing seed very thickly one year, resulting in stunted plants which produce very small bulbs. These bulbs are very easy to set out and grow into mature bulbs the following year, but they have the reputation of producing a less durable bulb than onions grown directly from seed and thinned.
Choices of seed varieties is far greater than that of sets and growing from seed will let you choose varieties to suit your own needs, such as the desire for an early-season sweet onion or a late-season keeper. Most onion experts agree that, diversity aside, onions grown from seed perform better than those grown from sets. They are less prone to disease, they store better, and they bulb up faster. Growing from seed will give you first year onions that will almost never bolt to seed, are all edible and will store well. Seed will give a stronger bulb which is also more useful for pickling and for storing.
Natural Dyes: The the skin of a white onion will give shades of orange while the skin of the red onion can be used to create a medium green, slightly lighter than forest green.
How to slice an onion without crying: Freeze the onion for ten minutes before cutting. The sulphuric compound that leads to tears will not react as quickly when it’s cold. If you forget, just light a candle, as a burning flame can burn away the sulphuric fumes.
Other Uses: If you have just painted a room and the fumes are a little overwhelming, slice an onion in half and place it in a bucket of cold water. Leave the bucket in the room overnight. The fumes will magically dissapear (or a least be reduced a fair bit).
Prior to Linnaean taxonomy the Onion family was spread over four genera. The bulb Onion, Shallot and Welsh Onion were found in the Cepa genera. Garlic was placed in the Allium genera, Leeks were listed as Porrum and the Chive was classed as Schoenoprasum, its current species name. The genus name, Allium comes from the Celtic "All," meaning pungent, the species name, cepa, is from the Roman "cepae," or onion. The common name onion seems to come from the Latin "Unio," or one, signifying that the bulb is of one unit.