Dung or compost must not be used with turnips, but it is an advantage if a plot can be chosen that has been manured for a previous crop. Then it will be sufficient to dig thoroughly in autumn or winter and dust the surface with superphosphate (3 oz. per square yard) and sulphate of potash (1 oz. per square yard) prior to sowing. If such ground is not available, it will be advisable in addition to give a dressing of soot (8 oz. per square yard) or sulphate of ammonia (4 oz. per square yard) at the same time. Small successional sowings should be made every three or four weeks from early March until mid-July to supply young roots to be pulled as required. For winter storing, a sowing may be made during the latter half of July.
Turnip tops for use as greens in the spring are produced by sowing seed in drills 18 in. apart in early September and leaving the plants unthinned to stand the winter. Seed for the successional sowings may be sown in drills 4 in. deep and 12 in. apart, but for the winter crop the distance between the rows should be increased to 15 in. Similarly, it will be sufficient to thin the summer crops to 4 in. apart, but the winter turnips must have twice this room. Winter turnips should be lifted for storing in October or early November. They are pulled out, the tops are cut off, and the roots are stored in a shed or cellar. Varieties are Golden Ball, Early White Milan, and Early Snowball for summer supplies, Greenttop Stone for winter and supplying turnip tops.
Club root, cabbage gall weevil, and flea beetle are the principal foes.
The first sowing, out of doors or under cloches, may be made from mid-March to mid-April with a second successional sowing in May. Sow seed thinly inch deep in rows 1 foot apart. Dust seedlings with derris to control flea beetles and hoe to keep down weeds. Thin the seedlings to 4 inches or so apart and water in dry spells. Quick growth with no checks at all is essential for succulent summer turnips. Start pulling for use when the turnips are sufficiently large. If left to age they become coarse and fibrous. Sow seed of winter turnips similarly, in late July or early August. Water seed drills if the soil is dry and sow after the water has drained away. Dust the seedlings with derris and thin to 9 inches apart. Winter turnips are often left in the ground and pulled when wanted. In colder parts the roots are best lifted in the autumn when the outer leaves are yellowing. Cut back the foliage to about an inch from the crown and shorten long tap roots by a few inches before storing the roots in moist sand or ashes.
The root vegetable, Brassica campestris rapa (syn. B. rapa), has been grown in Britain since the sixteenth century. The roots are global or flattish round. A well-drained sandy loam is suitable for both types—summer and winter. But if the soil is light and sandy, it dries out rapidly and turnip flea beetles flourish. A heavy soil is unsuitable for summer turnips but is usually suitable for the winter type. Both very light and heavy soils are improved by regular winter dressings of manure, etc. A site that was manured for a previous crop should be chosen.
For a supply of turnip tops for ‘greens’ in spring sow seed of a suitable variety in August quite thickly in Finch-deep drills spaced at 18 inches apart. In colder areas the plants benefit from cloche protection during the winter. When picking leaves for use take but one or two from each plant.
- Summer ‘Early Snow-ball’,
- ‘Early White Milan’,
- ‘Red Top Milan’,
- ‘Golden Ball’; winter
- ‘Manchester Market’;
for turnip tops
- ‘Hardy Green Round’,
- ‘Green Globe’.
Garden swedes, such as ‘Bronze Top’ and ‘Purple Top Improved’ often replace winter turnips. Swedes are hardy, and the large roots may be left in the ground until Christmas at least. You can also lift the roots in October, cut off the foliage and store the swedes indoors in dry sand.
Swedes do best in an open, sunny site, and the soil should have been well manured or composted for the previous crop. A sprinkling of a general compound fertiliser may be made before sowing if the soil is not too fertile. Sow very thinly in May or early June in 1-inch drills spaced at 15 inches apart. Thin the seedlings to 12 inches apart and, if growth appears rather slow during the summer, top-dress and hoe into the ground nitrate of soda at the rate of 1 ounce to a row of 10 feet. This fertiliser should be watered in, if the season is a dry one. Hoe to keep down weeds. Alternatively, mulch with chopped straw or sedge peat in late July.