440 
VEGETABLE GARDENING 
for the home table, their structure should be modified by 
the addition of large amounts of vegetable matter. The 
vine growth is likely to be excessive on stiff soils and the 
tubers are rough and unsymmetrical. New land is re- 
garded as especially valuable for this crop. Calcareous 
soils, when properly handled, often produce good results. 
Some of the driest and most sandy soils give good yields 
of fine tubers when seasonal conditions are favorable. 
Sweet potatoes can often be made to pay on lands too 
poor for cotton or tobacco, although the highest yields 
cannot be expected in impoverished soils. 
629. Seed. — The tubers for the propagation of plants 
for next year’s crop should be selected when the crop is 
dug. Some growers attend to this matter with the great- 
est care. Individual hills are studied and the tubers are 
chosen with reference to productiveness, size, shape and 
uniformity. With white potatoes, hill selection has 
been clearly demonstrated to be valuable, and there are 
reasons for its practice with sweet potatoes, but the ex- 
perimental evidence in its favor is not very conclusive. 
The same may be said with reference to the use of 
tubers of various sizes. The experiment stations have 
not been able to show that it is profitable to use large 
tubers for seed, although there is some evidence in their 
favor. In many regions of prominence the small tubers 
are chosen because they keep better than large ones 
in storage, are worth the least on the market, and a 
bushel will produce a greater number of plants than 
larger tubers. When several “drawings” are made, from 
3 to 4 bushels of seed potatoes are required to grow 
enough plants for an acre. When only one pulling is 
made, 6 to 8 bushels are required. The practice of New 
Jersey growers is to bed 1 bushel of seed roots for each 
1,000 plants desired (Farmers’ Bulletin 999). A bushe' 
will produce from 2,000 to 2,500 plants when two 
drawings are made. Varieties vary greatly in their 
