The Culture of Vegetables and Flowers From Seeds and Roots, 16th Edition, by Sutton and Sons
Brassica oleracea bullata
The Savoy Cabbage is directly related to Brussels Sprouts, though differing immensely in appearance. It is of great value for the bulk of food it produces, as well as for its quality as a table vegetable during the autumn and winter. In all the essential points the Savoy may be grown in the same way as any other Cabbage, but it is the general practice to sow the seed in spring only, the time being determined by requirements. For an early supply, sow in February in a frame, and in an open bed in March, April, and May for succession. This vegetable needs a rich deep soil to produce fine heads, but it will pay better on poor soil than most other kinds of Cabbage, more especially if the smaller sorts are selected. Savoys are not profitable in the form of Collards; hence it is advisable to plant in the first instance at the proper distances, say twelve inches for the small sorts, eighteen for those of medium growth, and twenty to twenty-four where the ground is strong and large heads are required. In private gardens the smaller kinds are much the best, but the market grower must give preference to those that make large, showy heads.