640 BADICACEOUS ESCULENTS. 



that a crop planted in the first week of March exceeded that planted in the 

 first week of April by about a ton and a quarter per acre. It must be 

 obvious, however, that the propriety of planting thus early will depend upon 

 the nature of the soil, and that it is too early for wet, heavy land, although 

 it is the best season for light soils. In reality, land cannot be advantageously 

 cropped with potatoes until all the superfluous moisture has drained away or 

 evaporated. 



" In all cases the plantation should be made in open places, fully exposed to 

 light. The quality of the potato depends upon the quantity of starchy 

 matter (mealiness) it contains. Now this starchy matter can only be 

 formed abundantly by the action of light upon the leaves, which are the natural 

 laboratory in which such secretions take place, and from which they are con- 

 ducted by sure, though hidden, channels to the tubers where they are stored 

 up. To plant potatoes, then, in plantations or orchards, or under the shade 

 of trees, is to prevent the formation of the mealiness which renders this 

 plant so nutritious, and to cause the tubers to be watery and worthless. 

 This is probably one reason why field potatoes are usually better than those 

 raised in gardens. 



" But the potato may suffer by its own shade as much as by the shade of 

 other plants. When its sets are planted too close, the branches shoot up 

 and choke each other, the leaves of the one smothering the leaves of the 

 other ; so that the more sets are planted, the smaller will be the crop of 

 this plant. Mr. Knight was the first to point out this common error, and 

 to show that there is a certain distance at which the sets of each variety of 

 potato should be planted so as to insure the greatest produce. By planting too 

 close, the plants smother, and so injure each other ; by planting at too great a 

 distance, land is uselessly wasted. Practice and well-conducted experiments 

 demonstrate what theory suggested, that the true distance at which potatoes 

 should be set is to be determined by the average length of the haulm. One 

 kind of potato is dwarf, and only grows six inches high ; its rows should, 

 therefore, be only six inches apart. Another kind grows three feet high, 

 and its rows should be three feet asunder. The space from set to set in the 

 rows appears to be immaterial ; six or eight inches are sufficient for those 

 which grow two feet high. An experiment formerly conducted by the 

 writer of these observations showed that, when the Early Champion, a sort 

 whose stems are on an average two feet long, was planted in rows two feet 

 six inches apart, the produce was 15 tons 19cwt. 82 Ibs. net per acre; while, 

 by reducing the distance between the rows to two feet, the produce was 

 increased to 24 tons ; but by diminishing it still further to one foot six 

 inches, the produce was reduced to 22 tons 16 cwt. 102 Ibs. ; and where the 

 rows were only six inches apart, the produce fell to 16 tons 17 cwt. 110 Ibs. 

 Such an experiment seems conclusive. 



" The depth at which the potato should be planted is not ascertained 

 with the same exactness, nor perhaps can it be ; for much will depend 

 upon the nature of the soil. In warm, dry land, we regard nine inches as 

 not too deep," provided the sets are large and strong; "in cold, stiff soil, 

 four inches would be better. Six inches is a good depth for average land," 

 and, indeed, may be considered the best depth in most soils. Weak sets do 

 not come up well at nine inches deep; but, on the contrary, four inches is too 

 shallow, occasioning the tubers to be partially exposed to the light, and hence 

 to become green. If, however, the land is so shallow as to admit of no 



