In the past, a special bed was reserved for the onion crop. The onions from this heavily-manured site were often massive, but the growing of the same crop on the same soil season after season generally resulted in a build-up of onion pests and diseases. The monster onions were not noted for their good-keeping qualities.
Nowadays, onion cultivation is fitted into rotation and manuring programmes Onions may be raised from seeds or from sets. Sowings may be made in the open or in the cold frame in August, in January or February in the heated greenhouse, or in the open garden in March and April. Cultivation For the August sowing, choose a sunny position and fork the soil lightly, removing all weeds and their roots.
Do not add any manure or fertiliser. Firm the bed and rake it well before making 1-inch deep seed drills at 9 inches apart. Sow the seed reasonably thinly, fill the drills with soil and firm it gently. Hoe between the seedlings in late September or October to keep down weeds. In March, use the fork to lift all of the seedlings and set them on a prepared bed, allowing 8 inches between the plants and 15 inches between the rows. Spread out the roots in the planting holes made with the trowel and if the plants do not remain upright, draw some fine soil round them. Rake away this covering when the plants have become established. If you make this sowing in the cold frame, do not set the light in position until October.
Use the onion hoe to remove weeds, and give plenty of ventilation throughout the winter except in very severe, frosty weather. The seed-lings may also need watering around Christmas and in February. Choose mild days for watering and leave the light fully open for several hours afterwards. Set out frame-protected plants in March. The winter sowing in a slightly heated green-house is made in boxes or pots of seed compost. Sow seeds 1 inch apart or, if they are sown closer together, prick off the seed-lings when they are large enough to handle. Harden them off in the cold frame in March and plant them out late that month.
When the seeds are to be sown directly in the soil where the plants are to grow, the bed should be well prepared. Digging and manuring will have been carried out during the late autumn or winter and the soil needs raking before sowing so that the bed is level, even and free of large clods and stones. Sow thinly in 1-inch deep drills, spaced 1 foot apart. After sowing, fill in the drills and firm. Do not tread heavily on a clay soil. Keep the seedlings free of weeds by hoeing between the rows during April and May, and pull out any weeds in the rows. Start thinning the plants in mid-June and continue thinning until mid-July by which time those which are to remain should have at least 6 inches of row space. When thinning, take great care not to break roots or foliage and never leave either on top of the soil. The odour of the broken plants attracts female onion flies and their small maggots ruin many onion crops. If the soil is on the dry side, water both before and after thinning. Use the immature onions in salads.
Continue weeding the onion bed until July. During that month, or in August, the foliage becomes yellow and topples to the soil. Here and there it may be necessary to bend the foliage of a plant down-wards. No further weeding is necessary and the crop is left to ripen. When the foliage is brown and brittle, choose a dry, sunny day, pull up or dig the onions from the soil, and spread them in the sun to complete the drying process. In wet weather, spread the onions on the green-house bench or under cloches. When the onions are quite dry, rub off soil, dead roots and dry, loose scales. Store the ripe onions in trays in a cool dry place, or better still, rope the crop. Hang the ropes in an outhouse or in the garage.
These are small onions grown by specialist nurserymen. The crop is dug and dried in the previous summer and offered for sale in the early winter and spring. One pound of sets is sufficient for the average garden. Small sets are considered of better quality than large ones. Do not leave onion sets in bags after purchasing them, but spread them in a tray in a cool place before planting them in March. Prepare the bed as for seed sowing and plant the sets 6-8 inches apart in 1-inch deep drills. Except for hoeing to keep down weeds, little in the way of cultivation is necessary.
The feeding of the plants with fertilisers may result in `bolting’. In late July, loosen the soil around the swelling bulbs to expose them to the sun. This must be done carefully because the plants may be blown down by strong winds if the roots are broken. The foliage will topple to the soil in August and from then on harvesting and storing are as for onions from seeds.
Where maincrop onions are raised from sets, `spring’ or salad onions are grown by sowing seeds of `White Lisbon’ in August or in March. In colder parts, the August sowing needs cloche protection from October until the spring. Although the bed should not be a rich one, it must be well-drained. Sow quite thickly and hoe to remove weeds in September and again in March. Start pulling the small onions for salad use in May and continue to pull until July. The March sowing provides salad onions from July until the autumn.
The onion is one of the few vegetables allowed 20 points at shows where the organisers follow the rules laid down in the Horticultural Show Handbook of the Royal Horticultural Society. For this reason, keen showmen very often choose this vegetable as one of their exhibits. The plants are raised in gentle heat in the winter and the seedlings are potted into 3-inch peat or clay pots. After they have been hardened off the plants are set out on a well dug and richly manured bed in early April. At least 1 foot is allowed between the plants and 18 inches between rows. Weeding and watering are carried out, when necessary. Together with small but regular feeds of liquid manure or fertiliser. Great care must be taken to prevent overfeeding which leads to `bolting’ or to bulbs with thick necks. All watering and feeding must cease when the onions reach their full size. Size and uniformity can earn 10 points.
Onions for Pickling
`Marshall’s Super Pickle’ is a new onion with the round shape and size as favoured by the com-mercial pickler. Seeds of this variety or of any maincrop suitable for spring sowing are sown rather thickly in ,4-inch to 1-inch deep drills spaced at 9 inches apart in soil of low fertility during March or April.
Weeding must be attended to regularly but the onion plants are not thinned. Harvesting is carried out when the foliage is dead, brown and brittle.
For white cocktail onions seed of ‘Silver Skin’ or ‘Pearl Pickler’ is sown quite thickly in April or early May. The soil should be reasonably fertile. If grown in a poor soil the onions are liable to be too small for use. Apart from weeding no cultivation is necessary and the plants are not thinned. The crop is harvested promtly, the bulbs produce fresh foliage.
Feeding and Fertilizer Alternative Methods
Dung or compost should be dug in as long as possible in advance of seed sowing at 1 cwt. to 12 sq. yd. Bonfire ashes can also be worked in at ½ lb. per square yard. Alternatively, give sulphate or muriate of potash just before sowing at 1 oz. per square yard. In any case apply either basic slag or bonemeal at 4 oz. per square yard, with the dung, or superphosphate of lime, 2 oz. per square yard, before sowing. Seed for the main crop should be sown as early in March as the state of the ground will permit. Sow thinly in drills in. deep and 9 in. apart. Later, thin seedlings to 6 in. apart. This can be done gradually, the thinnings being used for salads.
For an early supply, seed may be sown in the same way at the end of August. The seedlings will then stand the winter without thinning, and in the spring some can be used for salad and some be planted 6 in. apart in rows 1 ft. apart in a well-prepared bed. Bulbs can be used direct from the ground from June to September, while from the spring sowing bulbs will be lifted in early September and stored for autumn and winter. An alternative method is to sow thinly in boxes in a warm greenhouse in January and harden off for planting out in April.
Give one or two top dressings of nitrate of soda, 1 oz. to 12 ft. of row, during May and June, to encourage growth. In mid August the leaves should be bent over at the neck to check further growth and encourage ripening of the bulbs. Lifting should be done with a fork in September. Leave the bulbs on the ground or place them in a greenhouse, frame, or shed to dry out for a few days and then store in a cool, dry place. Bulbs with thick soft necks do not keep well. Another method of growing onions is by sets or small bulbs. These are planted in April 6 in. apart in rows 12 in. apart. The sets should be pressed firmly into the soil to a third of their depth.
Varieties for spring sowing are Ailsa Craig, James’s Keeping, Bedfordshire Champion, and Rousham Park Hero. For autumn sowing, Giant Rocca and Solidity are recommended. White Lisbon is useful for salads. Stuttgarter Reisen is a good variety for sets.
Mildew, neck rot, white rot, eelworms, and onion fly are the worst foes.