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.
This is a most important crop, and if the heads can be obtained early very good prices may be realized. For the first early crops such varieties as "Express", Dwarf Early Erfurt (noin hatif d'Erfurt), Early Paris (tendre de Paris, or Petit Salomon), and Early Snowball (Botrfe de Neige) are chiefly grown. For second-early crops Second-early Paris (demi-dur de Paris or Gros Salomon) and Lenormand are mostly grown, while a non-catalogued variety called "Driancourt" also finds favour with some growers.
For late crops in the open air it would be difficult to beat Autumn Giant, Walcheren, and Early London or Early Dutch.
The early varieties are sown during the first fortnight in September on an old bed or even in the open border specially prepared: or under lights or cloches if the weather is unfavourable. In due course the seed-lings are transplanted as soon as two leaves have been made beyond the seed leaves, and from 150 to 220 are placed under each light, so that one three-light frame may hold from 450 to 660 plants. Plenty of air and light must be given on all favourable occasions, otherwise the plants may grow too quickly and become lanky. Sometimes this happens in spite of every care in very mild winters, and then there is no option but to transplant a second time, putting only half the number of plants under each light, or about a dozen under each cloche. In severe weather the frames and cloches must be covered with mats, and manure must be heaped round the frames, while leaves and litter are also placed around the cloches when the frost is very severe.
Early in December the plants will be ready for placing on the north and south edges of the hotbeds which have already produced a crop of Crepe Cabbage Lettuces, and Radishes, and are maturing a crop of Carrots. Six Cauliflowers are placed in each light, three at the top (north) and three at the bottom (south), while an extra one is placed at each end of the frame. The temperature at this time is from 65° to 75° F. The first heads are fit to cut about the third week in March, and the first crop of Cauliflowers is finished about the end of April.
While this particular crop has been maturing, succession crops have been planted at intervals of about a fortnight in other frames in precisely the same way, so that the Cauliflower season is greatly extended.
The second early varieties may be sown at the same time as the first early ones, and treated in the same way to produce heads in natural succession. And in February and March and April a sowing may be made of the later varieties to produce plants for the open ground in May and June, to come into successional bearing in autumn.
Cauliflowers are not only grown in the frames in the way mentioned, but plants are also placed in the spaces between the north and south row of bell glasses that are sheltering Cos Lettuces in early spring.
From the beginning of February onwards Cauliflowers are also planted about 2 1/2 to 3 ft. apart on warm sunny beds or borders on which Radishes and Carrots have just been sown in the same way as under the lights already described. But even the space between the Cauliflowers is not wasted. A Cos Lettuce is planted between every two, while on the margins of the beds or borders a row of Cabbage Lettuces are planted. The diagram will show how this is done.
Fig. 527. - Diagram showing how Cauliflowers (•), Cos Lettuces (O), and Cabbage Lettuces ( x) are planted on open-air beds.
Thus five different crops are on the same piece of ground at one time: (1) Carrots and (2) Radishes (germinating) and (3) Cabbage Lettuces, (4) Cos Lettuce, and (5) Cauliflower. The Radishes come off first, the Cabbage Lettuces second, the Cos Lettuces third, the Carrots fourth, the Cauliflowers fifth, and then the bed can be turned over easily and re-cropped in a similar way, or with whatever crops the grower thinks will pay him best. And this in the open air in early spring. There is nothing like it in British market gardens, and never was.