This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
The Onion (Allium Cepa) is a hardy biennial bulbous plant, and originally came from central or western Asia. It is thought that the name has been derived from a Jewish city called Onion, which once existed near the Gulf of Suez, and was built by one Onias about 173 B.C. As an article of diet the onion has probably been in use from time immemorial. It is said to have been grown by the Egyptians two thousand years before the Christian Era, and gradually found its way across Europe by way of Greece and Italy. Throughout southern Europe the onion is an important article of food amongst the poorer people. Owing to the warmer climate the bulbs are milder and sweeter in flavour than our own produce. The importations of onions are large, over 5,000,000 cwt. being now landed on our shores between January and the end of July.
Either cooked or raw, the onion is very nutritious, and easily digested by most healthy folk. Boiling or roasting makes it more acceptable to delicate people, and amongst its other valuable properties is the one that its juice has the reputation of dissolving calculus in the bladder.
As a British crop the Onion is not extensively grown. According to the Returns of the Board of Agriculture only 4222 ac. are recorded for the crop in Great Britain, while no records appear in the agricultural statistics for Ireland. Bedford seems to be the largest Onion-growing county in the kingdom, having 1000 ac; Essex has 569 ac, Kent 356 ac, and Worcester 222 ac. Scotland has 191 ac, and Wales 29 ac Although the British climate cannot compete with that of southern Europe for warmth and sunshine, there is no reason why the most favoured parts of England and Ireland should not make more of the Onion-growing industry. As may be seen from the ash analysis at p. 109, Vol. I, the Onion takes large supplies of potash from the soil, and also, but in smaller proportions, phosphoric acid, lime, sulphuric acid, and soda. The average market-garden crop is from 12 to 15 tons per acre. An average Onion, as sold in the market, weighs about 8 oz., and has a circumference of 10 in. in the widest part. Many are larger and heavier, but others are smaller and lighter (3 dozen to 1 lb.), and preferred by many. In private gardens, bulbs often weigh from 1 lb. to 3 lb. each.
The great possibilities of Onion-growing may perhaps be realized from the following figures. Assuming the rows to be 1 ft. apart, and the plants, after thinning out, to be 3 in. apart, as a fair distance for market-garden culture, there would be 174,240 to an acre. At an average weight of 8 oz. each the yield per acre would be nearly 39 tons. At £4 per ton this would represent £156 per acre for the matured crop, without counting the value of the thinnings for salads. If the plants are thinned out 6 in. instead of 3 in. apart, there would be 87,120 bulbs to an acre. These would yield 19 tons on the 8-oz. basis, and £76 per acre at £4 per ton.
Fig. 481. - A Heavy Onion Crop, the result of thinning out properly and good cultivation.
From experiments carried out on the Times Experimental Farm, 1910, the following results were obtained from a square chain of land from seeds sown in boxes in February, and transplanted, 12 in. by 3 in., in April (174,240 bulbs to the acre). The varieties of Onion were: "Ironhead", 2640 lb. (= 11.7 tons per acre); "Cream Globe", 2878 lb. (= 12.8 tons per acre); "Al", 3630 lb. (= 162 tons per acre); "Nonsuch", 3698 lb. (= 16.5 tons per acre); "Banbury", 3709 lb. (= 166 tons per acre); "Wroxton", 3960 lb. (= 176 tons per acre); Ailsa Craig", 4950 lb. (= 22.1 tons per acre). [J. W].