ONIONS 311 



somewhat earlier in the spring than do the light ones, and since 

 the early warming of the soil is essential to success in onion cul- 

 ture, this may be more than a fad. 



Onion seeds are slow to germinate, and any method of cultiva- 

 tion or any soil that promotes the germination of the seed early 

 in the season is an advantage. 



Preparation of the soil. Soil for the successful cultivation of 

 onions should be very rich. If the ground has not been previously 

 used for market-garden purposes, the preparatory treatment usually 

 consists in growing a crop of clover, cowpeas, crimson clover, or 

 some other nitrogen-gathering plant, and plowing it under before 

 planting the onions. This means at least one year of preparation. 

 In addition to the turning under of the green crops, from 25 to 

 50 yards of well-rotted stable manure are necessary upon even the 

 best and richest alluvial soils, and in some instances this is sup- 

 plemented by from 600 to 1500 pounds of high-grade fertilizer in 

 which the nitrogen used is in the form of nitrate of soda. A fer- 

 tilizer containing 3 per cent of nitrogen, 6 per cent of phosphoric 

 acid, and from 8 to 10 per cent of potash will be found advan- 

 tageous on nearly all soils. Soils which will not be injured by 

 exposure to freezes during the winter should be plowed in the 

 fall. The green crops and the manure, unless it is very fine, 

 should also be plowed under in the fall. Fine manure should be 

 reserved for spring application and then disked or lightly plowed 

 in. Peaty soils and those upon which heavy green crops have been 

 turned under are apt to be acid. To remedy this, apply lime. 



A deep seed bed is important for all truck crops, but no attempt 

 to form one in a single season should be made. If the ground has 

 already been cultivated to a depth of 6 or 8 inches, it would not 

 be wise to plow more than I inch below this the first season ; but 

 the plowing should be deeper each season until the seed bed is 

 10 inches in depth. As a rule, all deep cultivation should be done 

 in the fall, and the ground left rough during the winter so that it 

 will come into order as soon as possible in the spring. With some 

 soils it may be advantageous to throw the earth into ridges with 

 the lister in the autumn ; and early in the spring, when the tops 

 of the ridges have dried out, to level the ridges and then bring 

 the ground quickly into cultivation. 



