36 Market Gardening, 



decidedly in contrast with the old at all points — and 

 seems at all points to have the advantage of it. 



The correct theory of rotation proposes, while mak- 

 ing immediate use of the plant food already in the soil, 

 at the same time to prepare the soil for producing the 

 other crops that are next to follow. In arranging for 

 a system of rotation, we should aim to grow such crops 

 and under such culture as will keep the soil well sup- 

 plied with humus, or plant food. 



No exact rules can be laid down as to the order in 

 which crops should be planted in rotation, but it 

 should be remembered that some plants by nature 

 feed near the surface (like com, for instance), while 

 others, take clover for an example, draw the most of 

 their nourishment from deep down in the soil. 



The object should be always to avoid following one 

 deep-rooted crop by a similar one ; taking great care to 

 alternate them with others as constantly as possible. It 

 is well, when practicable, to follow a slow-growing crop 

 with one of quick growth, or 7nce versa. No root crop 

 should follow one of a similar character ; nor should 

 vines follow vines. Alternation is always beneficial. 

 Onions are very generally regarded as an exception to 

 this general rule, and to some extent they doubtless 

 are so; but I have not found it advisable to grow them 

 on the same ground many consecutive years, as they 

 are far more likely to become maggoty, and otherwise 

 diseased, than when the ground is changed once in 

 two or three seasons. 



There is considerable truth in the suggestion that a 

 good rotation can only be had when conducted by 



