Growing Onions

To obtain those large globular bulbs, imported in quantity from Brittany each year, it is necessary to give the onion a long season of growth and iii the colder parts of Britain this is possible only if sets are planted rather than seed. North of a line drawn from Chester to the Wash, it will be necessary to raise seedlings under glass, preferably in a warm greenhouse, otherwise in an average summer they will fail to attain maximum size and to complete their ripening.

As onions may be grown in the same ground year after year, a special bed may he prepared, incorporating humus to a depth of 2 feet together with sonic well decayed manure. At the same time, work in 4 ounces per square yard of basic slag and 2 ounces of sulphate of potash just before the sets are planted ; or give a liberal dressing of bonfire ash. The bed should be brought to a fine tilth and he allowed time to settle before planting. Certain growers famed for their mammoth onions will roll the bed before planting.

The sets are just pressed into the soil, allowing 6 inches between the bulbs and 12 inches between the rows. The best variety to grow from sets is `Stuttgarter Riesen’, approximately 300 sets weigh. They should be firm and plump when planted and 15-20 min. in circumference. This variety makes a large bulb which keeps well through winter, and does not ‘bolt’ readily in warm weather.

Where growing from seed (and one ounce of seed will produce sufficient plants for a mo feet row spacing the plants 6-7 inches apart) sow in a cold frame or in boxes in a heated greenhouse containing John ‘tines compost. Sow mid- January when the seedlings will he ready to transplant into deep boxes containing a slightly richer compost, early in March. If raising the plants in heat, provide a temperature of 5o”F. and harden the plants before they go out.

Seed may also be sown under cloches early in February or, in the warmer parts, in October and may stand unprotected over winter. An additional advantage with autumn sown onions is that they rarely suffer from onion fly attacks. Sow thinly in shallow drills and dust with Calomel before sowing.

The plants should go out into prepared beds early in April. Lift them from the boxes as they are required so as not to expose the roots to the sun or a drying wind unduly and plant so that the bulbous part is half out of the ground. Before planting, clip the roots into Calomel paste as protection against onion fly and as a further precaution, dust with Calomel four weeks later.

Whilst growing, keep the hoe moving between the rows and water copiously in dry weather. A weekly feed with dilute manure water will increase the size of the bulbs- By mid-August, watering should be withheld to enable the bulbs to finish ripening and in this they will be assisted if the tops are bent over, just above the necks, to prevent them from seeding.

Towards the end of September, when the soil is dry, the bulbs are lifted and laid out for eight hours on the soil to complete their drying. They are then cleaned of any loose skin and the tops removed, leaving only a small portion necessary to string them together and hang them in a dry, airy shed to be used when required. If the autumn is dry after a wet summer, the bulbs should be left.as long as possible before lifting and should then be left on a stone path for fully a week to dry completely. If excess moisture remains in the bulbs, they will begin to grow again in storage or may begin to decay.

Onions are amongst the most rewarding of vegetables for the exhibitor for with good culture it is possible to grow them to enormous size, of 1 en weighing 4 pounds or more and, so as not to crack the skin, they should be lifted with both hands.

Exhibitors will go to great lengths to prepare the bed, of 1 en working it 3 feet deep and incorporating some lime rubble, leaf mould, decayed manure and material from the compost heap. The soil is pulverised for several months to bring it to a fine tilth before planting. The seed is sown outdoors in autumn or in January in a warm greenhouse, the plants being grown on in small pots in prepared compost from which they are planted out in spring after hardening, without disturbing the roots. The ground should. be given a liberal dressing of soot before planting for this helps it to retain the warmth of the sun and also stimulates root action in the soil whilst it is also a deterrent to onion fly. Where growing for exhibition, at least I s inches should be allowed between the plants in the rows.

The bulbs must be harvested with care. Lift with a fork inserted into the ground well away from the bulb and after loosening, use both hands to lift the bulb from the ground. After drying, cut off the roots close to the bulb and remove any outer layers of skin which may show markings. The top is cut hack to 3 inches and the remaining leaf is bent over and tied with raffia.

Pests and Diseases
DOWNY MILDEW This attacks the plants late in their life, a white .coating of fungus appearing on the leaves which, if unchecked, the back leaving the bulbs unable to develop. It is most prevalent in a wet humid season but may be controlled by dusting the plants with a mixture of lime and sulphur or by spraying with sulphide of potassium, one ounce dissolved in 2 gallons of water.

EELWORM The pointed nematodes enter the bulbs from the soil causing large brown areas of decay which are where the female lays her eggs; upon hatching the grubs devour the tissues of the bulb. Onion seed is now protected against seed-borne eelworm infection by fumigation with methyl bromide gas.

ONION FLY By far the most troublesome pest: the flies lay their eggs in the soil during May and June then the maggots tunnel into the bulbs causing the leaves to turn yellow and making the bulbs useless for any purpose. Dusting the rows with Calomel before sowing and dipping the roots of young plants into Calomel solution before planting will prevent an attack.

SMUT This attacks seedlings at soil level and is so destructive that the Ministry of Agriculture has classified it as a ‘notifiable’ disease. Black spots appear on the bulb scales and leaves and cause the plants to die back: the spores can remain active in the soil for 20 years or more. Immersing the seed in fin-math’ (t pint to 16 gallons of water) for an hour before planting will ensure freedom. Formalin is a poison and must be used with care.

WHITE ROT This fungus appears at the base of the bulb as fluffy white mycelium. Later black sclerotia develop on it, which detach themselves and remain in the soil for years. The sclerotia may be present in untreated seed samples so that specialist seedsmen treat their seed with Calomel before packeting. Five ounces of Calomel to pound of seed is considered satisfactory.