This section is from the book "The Gardener V3", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
These are perhaps of more value than Parsnips to the owners of small gardens, and they are more generally used. We recommend pretty much the same treatment as described for Parsnips, but the main crop had better not be sown until the middle or latter end of April, according to the weather. A small bed of Early Horn may, however, be sown in March in some sheltered corner in the full sun, or even at the end of February if a slight hotbed can be afforded them under the protection of an ordinary cold frame. Should young tender Carrots be wanted all through the summer and autumn, sowings may be made at intervals of a month up till July; but the returns, when the garden ground is limited, will scarcely repay the trouble. Still it often happens that different individuals have different wants, and we have indicated how a constant supply of small young Carrots may be had for as long a period as is possible with the ordinary appliance possessed by an ordinary amateur.
The main crop will require lifting and storing by October. They may be buried in sand in a dry corner of a cool cellar or shed, or they may be put in a pit in the same way that Potatoes are stored. If they are just kept from frost, it is enough. Heat will cause them to spring into growth, which spoils them.
Beet requires very similar treatment to the above. Sow about the end of March for an early supply; but many of these will run to seed in summer. For main crop sow at the end of April. Lift and store in the same way as recommended for Carrots. In lifting take care not to break or bruise the roots, and in cutting off the tops cut the tops only, but do not cut the roots, or they will bleed and allow the juice to escape.
Turnips for an early supply may be sown as directed for Carrots, in a hotbed or in a warm spot. Make two very small sowings in March for the chance of a few; but they will very likely run to seed before bulbing. Larger sowings may be made in April with more confidence, and in May onwards in whatever quantity may be required without any fear of their "bolting." The earliest-sown batches should get as favourable a position as possible, and in rich soil. One great means of preventing the early sowings running to seed is to keep them growing by means of rich soil. The later ones should be sown on ordinary soils, as rich soil in their case gives a tremendous crop of leaves, but very inferior roots.
The ordinary plan practised by amateurs, of making one sowing suffice, is not a good one. A small sowing every three weeks up till August is much better, as it keeps up a supply of young Turnips, which are always to be preferred to old ones. Should fly prove troublesome, a good dusting of soot or dry lime - not hot lime - when the plants are wet with dew will help them to pull through, and a watering with well-diluted paraffine-oil between, not on, the rows before the plants are up will sometimes prevent their appearance at all. 15 inches between the rows and 9 inches between the plants in the rows are suitable distances for those to be used young. Do not allow them to be crowded, as is usually the case, for they grow all to tops. Swedish Turnips for winter supply, or for furnishing Turnip-tops as a substitute for Seakale, require to be sown towards the end of May. Allow them 20 to 24 inches between the rows, according to the productiveness of the soil, and 1 foot to 15 inches between the plants. Store in pits like Potatoes, using plenty of straw and only a few inches of earth.