The secret of growing tasty turnips is to grow them quickly so that the crop does not ‘flag’ in dry weather. A light to medium, well-drained, cool soil not deficient in lime is necessary. Ground which was well manured for a previous crop is ideal. Always work in, peat etc., to help conserve moisture. Sow from the end of March to late July for sucessions and thin to about 6 in. for summer turnips — winter turnips can be allowed 9 in. For those who like the flavour, turnips can be sown in early September to furnish ‘tops’. Thinning is then unnecessary. Half an ounce of will a 50 ft. row.
Sow for winter use from mid-July to late August. In the south turnips can usually be left in the ground and pulled as needed but in the north it is advisable to lift in early autumn as the outerstart to ripen, storing in boxes of soil or sand, in a cool, frostproof shed. Recommended varieties include Unwin’s Utility which has a mild, pleasant flavour. Early White Stone (Six Weeks) is very quick maturing as is Extra Early Milan. Golden Ball (Orange Jelly) is very hardy and is a favourite for early autumn . Manchester Market is another variety for late .
The chief turnip pest is the well-known black bot, flea beetle or turnip fly which causes considerable damage among turnip and brassica- lings generally, especially in hot weather. It is chiefly active in May and perforates the leaves with ‘shot holes’. Seedlings may be completely stripped, a large sowing virtually disappearing in a few hours. There are several species of flea beetle, all 1/10 in. long and mostly black or near black with a yellow stripe on each wing-case. They invariably jump when disturbed.
Since this pest causes most damage before thehave passed the first 4- stage, in a hot, dry spring, turnip often make little progress after germination. Always keep them as cool as possible. Give a top dressing of any complete fertiliser to help the seedlings grow away rapidly.
Modern synthetic insecticides give complete control of this pest, provided they are applied in time. Apply anor gamma-BHC (lindane) dust as soon as the rows show green and repeat every 3 or 4 days during a hot spell until the seedlings are really established. As long as the plants are coated with the insecticide a serious attack will be warded off — a fresh application is only needed as advised or if rain removes the material. When an attack develops apply immediately. On no account delay dusting even for a few hours, otherwise the entire crop may succumb, necessitating resowing.
Brassica seed can also be dressed with a special gamma-BHC dressing to anticipate attacks.