This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Some years ago Violet growing was a lucrative business in many market gardens in Middlesex, Kent, and Surrey, but the encroachments of the builder have driven the industry farther afield. Violets are now grown in milder parts of the kingdom, and notwithstanding the keen competition from the importations from the south of France, from Christmas to March and April, British growers are able to secure a fairly good price for their produce, and that for bunches only about half the size of those from the Continent. The flowers are usually bunched with stalks as long as possible, and are surrounded with their own foliage. Indeed there are no Violets in the British markets to equal those from Devonshire, Cornwall, and the south of Ireland for fragrance or size. Of late years, in the neighbourhood of Skibbereen, County Cork, the Violet industry has been revived on a fairly large scale, and one grower, Mr. W. Miles, of Ballydehob, is proving that the culture on a commercial basis is quite possible. He grows his plants in well-raised beds, each about 3¼ ft. wide, placing the Violets 14 in. apart. He gets the soil as rich as possible, and gives forty loads of good stable manure to the acre. Heavy soil is opened up with sea sand, grit, or ashes. As a rule rooted runners are planted, but unrooted ones give excellent results with such varieties as "Princess of Wales" and "Luxonne". The latter variety is particularly fine, and flowers from the middle of October to the middle of April, and will stand 12 degrees of frost with impunity. Princess of Wales, however, is much more tender, and must be grown in warmer and more sheltered spots. "Admiral Avellan" is a fine purple-flowered Violet from October till March, and has leaves that are particularly valuable for bunching purposes. The blue variety, "Californian", flowers from mid-November to the end of the season. To give some idea of the freedom of the variety "Luxonne", it may be mentioned that Mr. Miles picked 7000 blooms in one week from ¼ ac. of ground one winter when 14 degrees of frost were registered one night and 7 degrees the following one.
To secure the best Violets the soil should be rich and well drained and of a sandy loam. Large quantities of well-decayed manure should be worked in each year, and if the soil is trenched about every fourth or fifth year the tilth and temperature will be greatly improved. Cuttings or runners should be taken early in spring from the best and most free-flowering plants. Rooted cuttings or runners, if planted at 14 in. apart, will give about 30,000 plants to the acre, and under favourable conditions from 20,000 to 30,000 blooms may be picked weekly from such an area. The size of the bunches will depend, of course, upon the number of flowers put in them. Early in the season, perhaps, there will be only a dozen flowers to a bunch, and they may realize from 1s. to 1s. 6d., or even more, per dozen bunches. After Christmas, however, it may be necessary to put two dozen, or even three dozen, blooms in a bunch, and perhaps the price then will be as low as 6d. to 9d. per dozen bunches. Assuming that 30,000 Violet plants to the acre will each produce three dozen flowers during the season, a total of 1,080,000 (or 90,000 dozen) blooms will represent the crop. Taking two dozen flowers to a bunch, we have 45,000 bunches of Violets to the acre; and taking an average price of ½d. per bunch (or 6d. per dozen bunches), the gross receipts come to about £94. From this, however, must be deducted: rent and rates, say £4; manure, £5; digging and planting, £4; hoeing, £3; picking, bunching, and packing, £25 - making a total expense of £42 per acre, thus leaving £52 per acre for the grower. It would be well, however, to deduct 25 per cent from this for commission and contingencies, leaving a net profit of £39 per acre. So far as cultural details are concerned, the most important is to use the hoe as frequently as possible during the season, especially during a very hot and dry one, to keep the Red Spider at bay. This is also probably the best preventive against attacks of Violet Rust, caused by the fungus Puccinia violoe.
Besides the varieties mentioned above, the following are also worth noting: Marie Louise, rich lavender blue; Lady Hume Campbell, later and deeper in colour; Neapolitan, lavender with a white eye, among the doubles; and La France and the Czar among the single-flowered kinds.
Where frames, lights, and cloches are in use, in conjunction with hotbeds arranged as for the French system of intensive cultivation (see Vol. IV), there is no doubt that Violet growing could be made a more remunerative industry than at present in many parts of the kingdom.
Violets are grown in Worcestershire by the advanced type of commercial gardener. They are grown on narrow beds and borders, and the writer has seen the ladies bunching them at home in the evening. When they realize 8d. per dozen bunches and upward they are very satisfactory. Violets should be divided and replanted every spring, and the border should not be a dry one, either through adjacent trees or naturally, because Red Spider is sure to attack and spoil the plants during summer under those conditions. [J. U].