This section is from the book "The Gardener V2", 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 often planted before the ground is fit for their reception. More depends upon the proper preparation of the seedtubers, especially with the kidney varieties, than early planting; homegrown seed being preferable, as that bought is seldom so well kept. If the central shoot be uninjured in any way, and all side shoots either rubbed off or picked out with a knife, an evener growth and an earlier and heavier crop will be secured than would otherwise be the case. Some carefully preserve these shoots till planting-time, only to be damaged by careless planting; and for this reason I advocate drawing drills, and moulding over lightly with the hand, prior to a general levelling of the soil. Both the south and west borders are suitable for these early crops, and the soil should be as light and open as possible - heavy soils repaying for a good dressing of leaf or other light soils. I still recommend a liberal dressing of half-decayed manure, burying it in slightly below the tubers. Coarse tubers may result, which are objected to by many, and rightly so, perhaps; but unless a few are obtained, the crop, as a rule, will be a light one. Manure freely used for Potatoes, will also be found sufficient for most of the successional crops.
On light soils the rows may be placed 2 feet apart, and the tubers 9 inches asunder in the rows; on heavier soils the rows should be 30 inches apart, and the tubers from 10 to 12 inches asunder, planting deeply in the former instance, and shallowly in the latter. Moulding up is necessary where shallow planting is resorted to, and it should be practised where deeply planted, if the locality is liable to late frosts.
Good varieties to succeed either Veitch's Ashleaf or Mona's Pride are Early Hammersmith and Rivers's Royal Ashleaf, both of which crop heavily and are usually of good quality. Extra-early Vermont, which much resembles Early Rose, but is superior to that variety, is recommended for light soils, as it crops heavily, is early, and good in quality. Of round varieties, I prefer Fox's Seedling; and Alpha is also early and good. Early Oxford is of excellent quality, but the crops with me have been light. Early Coldstream makes too much haulm to please me, but is very good in other respects. Porter's Excelsior is an extraordinary cropper, but the quality, unfortunately, is generally inferior.
 
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