SELECTION OF SEED; FARM CROPS. 135 



thrives well on soils too poor and sandy for the white 

 potato, it must be well supplied with the mineral con- 

 stituents, particularly potash. 



Market-Garden Crops. These include a large num- 

 ber which are distinguished not so much by their place 

 or method of growth as the object of their production; 

 viz., earliness and succulence, rather than maturity of 

 crop. Lettuce, beets, spinach, radishes, onions, cabbage, 

 turnips, celery, asparagus, tomatoes, egg-plant, cucumbers, 

 melons, peas, beans, sweet corn, and many others, are 

 included under market-garden crops. 



To accomplish the two particular objects of their growth 

 requires a deep, warm soil, well supplied with vegetable 

 matter and with available forms of plant-food. Since 

 nitrogen is the element which encourages and stimulates 

 leaf and stem growth, its application, particularly in the 

 form of nitrates which are immediately available, is es- 

 pecially useful for all of these crops; and though peas 

 and beans belong to the legume family, they are materi- 

 ally benefited in their early growth by a supply of soil 

 nitrogen. 



Fruit Crops. These differ from other crops in that 

 there must be a longer season of preparation, in which 

 the growth shall be so directed as to prepare the tree for 

 the proper development of a different kind of product; 

 namely, the fruit. The fruit, too, differs very materially 

 in its character from that of ordinary farm crops, in that 

 its growth and development require a whole season; it is 

 necessary that there shall be a constant transfer of the 

 nutrition from the tree to the fruit throughout the grow- 

 ing-season. The growth for each succeeding year of both 



