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.
The Sweet Pea industry is now a very large one, thanks to the grace and beauty of the flowers, the comparative ease with which they may be grown, and the wonderful varieties that patience and skill have evolved during recent years. Growers of flowers or seeds have to thank the National Sweet Pea Society for the great advance this industry has made during the past ten or twelve years. Probably there are more tons of Sweet Pea seeds sown now than there were hundredweights a dozen years ago, while the size and beauty of the varieties and the range of colours provided are all due chiefly to the encouragement this society has given to its name flower. The seed-growers in Essex have added acres to acres year after year for the purpose of providing the necessary seeds, and the visitor to Kelvedon, Coggeshall, and surrounding district is greeted with the daintiest of perfume and a perfect ocean of lovely blooms. (See coloured plate).
In other districts large areas are devoted to flower culture for market. The earliest flowers grown under glass come chiefly from the Channel Islands, Cheshunt, Uxbridge, Worthing, Hampton, Uckfield, Haywards Heath, Saffron Walden, and Waltham Cross. Cornwall supplies early outdoor blooms, and then come quantities of flowers from such districts as those of Woking, Hanworth, Slough, Farnham, Rockley, Yarmouth, Guildford, and Cambridge.
According to the time of year, and also to the quality of the flowers, the market bunches consist of 12, 18, or 24 spikes. These bunches are packed in a single layer, and the box that finds most favour is one 24 in. by 15 in. by 3½ in.; it carries from eighteen to twenty-four bunches. The colours most in request at Covent Garden and other large flower markets are white, crimson, lavender, mauve, pink, rose, salmon, blue, blush, cerise, cream, and scarlet. Varieties of Sweet Peas that are at present very popular on the market are Dorothy Eckford, white, plain standard; Lord Nelson, blue, plain; Lady Grizel Hamilton, lavender, hooded; Mrs. Walter Wright, mauve, plain; Countess Spencer, pink, waved; Queen Alexandra, scarlet, plain; King Edward VII, crimson, plain; Prince of Wales, rose, plain; John Ingman, carmine, waved; Bolton's Pink, bright pink, plain; Clara Curtis, bright cream, waved; Coccinea, cerise, plain; Etta Dyke, white, waved; Evelyn Byatt, orange, plain; Frank Dolby, lavender, waved; Gladys Unwin, pink, waved; Helen Lewis, orange, waved; Miss Willmott, orange pink, plain; Mrs. Hardcastle Sykes, blush, waved; Nora Unwin, white, waved; Mrs. C. W. Breadmore, cream, rosy edged, waved; and Constance Oliver, cream pink, From this list it will be gathered that the market grower still retains many of the older varieties which the amateur and the exhibitor have practically discarded some time since.
1, Masterpiece. 2. Enchantress. 3. King Edward VII. 4. John Ingman. 5. Etta Dyke.
In the cultivation of Sweet Peas for market two points must always be kept in mind. These are: (1) that the production of early flowers is essential if good prices are to be obtained, because after the second week in July every garden has its quota of these elegant and fragrant flowers, consequently the demand slackens; and (2) that there is a limited demand throughout the season for flowers of the highest quality carried on long, stout stems.
Some growers put all their energy into the production of early blooms, and as soon as the prices for flowers drop, they clear out the Sweet Peas and follow them quickly with another crop. A few growers possessing sheltered and early land, and following a high system of culture, obtain early flowers, and, according to season, begin to market flowers late in May or early in June, and they manage to keep up a supply of high-class flowers throughout the season by the regular removal of old flowering stems and the encouragement of new ones. It is doubtful, however, whether it pays to keep Sweet Peas going for market purposes after August Bank Holiday, unless some handy holiday resort needs considerable supplies.
Covent Garden prices show plainly that the demand in the metropolis falls off considerably by the beginning of August. During the years 1909 and 1910 the average rates per dozen bunches during the last week of May have been from 2s. 6d. to 6s.; first week in June, 2s. to 6s.; second week in June, 2s. to 6s.; third week in June, 2s. to 5s.; fourth week in June, 2s. to 5s.; first week in July, 1s. 6d. to 4s.: second week in July, Is. 6d. to 3s. 6d.; third week in July, 1s. 6d. to 3s.; fourth week in July, 1s. to 2s. 6d; first week in August, 1s. to 2s.
Spring sowing out-of-doors is distinctly not the method to follow for flower production for market, because the flowers do not come early enough, nor do the roots strike deep enough to carry the plants safely over a dry period during the flowering season. Autumn sowing, following a quick crop for which the ground has been thoroughly well worked and manured, is the plan to follow where the soil and situation are suitable. Suitability in this instance resolves itself into well-drained soil of medium or lightish texture, and a site sheltered from the north and east, but open to air and sunshine.
A firm root run is not merely desirable for Sweet Peas, it is a necessity; therefore the site must be rolled or trodden over if it is ploughed or dug just previous to sowing. A good dressing of lime worked into the surface soil usually proves useful, but the need for it must be determined by the condition of the soil. Soot is also an excellent fertilizer, and its use serves to keep slugs and other ground pests in check. Lime and soot should not, however, be used together, i.e. at the same time, because if this is done the nitrogen in the soot is set free by the lime, in the form of ammonia, and thus the manurial value of the soot is largely lost. Superphosphate of lime and bone meal are excellent fertilizers for Sweet Peas, and in dry weather a little nitrate of soda (1 oz. to 3 yd. run) well watered in gives a wonderful fillip to growth.
Some Sweet Peas have smaller and lighter seeds than others, but as a general rule 1 lb. of seeds will be necessary to sow about 150 yd. run. On specially good soil the strongest growing varieties may be sown at the rate of 1 lb. to 200 yd. On an acre of land it is possible to have ten rows, 220 yd. long and 6 ft. apart. For supports, this amount would need from 330 to 400 bundles of sticks. Just as the price of land varies, so the price of seeds varies with the season and the variety, while in some districts the sticks required for supports are quite cheap and good, and in others more costly and often less useful even at the enhanced price. Growers must take all these points into consideration in their estimate when considering the advisability of growing Sweet Peas for market.
Besides the methods of spring or autumn sowing out-of-doors, there are also those of sowing under glass either in autumn or spring. Many growers sow hundreds of pots of Sweet Peas in October or early November in frames, and keep them just free from frost during the winter; four seeds in a 60-sized pot are sufficient. With reasonable care the plants so raised will be very sturdy by the end of March or early April, and if planted without root disturbance they speedily grow away and come into flower in June. A frame with several lights will hold a very large number of such pots, and if the pots are plunged to the rim in fine ashes there is little risk of danger from frost or from drought at the roots. In connection with this method the grower must always remember that Sweet Peas are hardy annuals, and therefore any coddling process will defeat the end in view. The other method is that of sowing in similar fashion, but in gentle heat, early in February, the seedlings to receive cooler conditions directly they are well through the soil, and be gradually hardened off as the season progresses. Whichever method is followed, and we consider autumn sowing in pots is the best, a few short twigs must be provided for each pot of seedlings to prevent the plants from falling over and clinging to those in a neighbouring pot.
Quite apart from the cultivation of Sweet Peas for outdoor flowering, is their culture for the production of early blooms under glass, and in some districts this proves a very paying crop. The seeds are sown in pots or boxes about the middle of October, placed in cold frames, and well watered, every care being taken to guard against trouble from mice and slugs. Plenty of ventilation is afforded as soon as the seedlings are through the soil, and should damp warm weather follow it may presently be advisable to pinch out the growing points just above the third pair of leaves. Early in December each plant should be potted in a 3-in. (60-sized) pot, in good loam to which some old manure and sand have been added. Plunge the pots in ashes and keep the frame rather close for two or three weeks after such potting; afterwards proceed to ventilate freely as weather permits. Real business commences early in February, as by this time growth will begin in earnest, and more root room will be needed. It must now be decided whether the Sweet Peas are to be grown in pots or whether they are to be planted out in light airy houses. If pots are to be used, then three plants should be put in a 12-in. pot, or two in an 8-in. pot, and these large pots should have three or four holes near the bottom, through which the roots may pass at a later date. A rich, fairly substantial compost is desirable, as also is firm, but not hard, potting.
At this period the plants must be kept well up towards the glass, because weak spindly growth cannot produce good blooms. When planting out is to be the method, then each Sweet Pea plant must be potted into a 48-sized pot, kept well up to the light until in March they are set out in trenches, in well-drained soil of a similar character to that used for the large pots. Careful ventilation, light houses, and a sufficiency of tepid water must be provided, and full advantage be taken of sun heat. When the large pots are well filled with roots the top growth will have made considerable advance, and the pots should then be partly plunged in trenches of rich compost - loam and old manure - or, if the houses are lofty and there is room for the plants, they may be stood on the stage and have soil banked round and under the lower part of the pot.
No matter which of these two methods is followed under glass the Sweet Peas ought to be about 2½ ft. high by the beginning of April; the haulm short-jointed, and the leaves deep green, and about 3 in. long by 2½ in. broad. During April growth will be fast, often J in. per diem. To secure the finest flowers the side growths must be removed until flowering commences. By May-Day, if treatment and conditions have been favourable, the plants should be about 4 ft. high, and showing plenty of spikes just ready to expand their flowers. Now is the time to commence feeding, and there is nothing better than soot water and liquid cow manure, using these alternately, and giving one watering of each per week.
Whether sticks, canes, or wire frames are used as supports must be left to the judgment of the grower; good results may be obtained with each, provided the growths are tied up regularly from February onwards. When the flowering season begins, all spikes must be removed when fit, no matter what the demand may be, for under glass, even more than out-of-doors, it is utter foolishness to allow flowers to seed, as this so taxes the energies of the plants that they will yield small blooms and short spikes, and rapidly pass out of flower. [c. H. c]