CULTURAL DIRECTIONS 421 



588. Fertilizing. — In the fertilizing of rhubarb the 

 grower should consider, (i) that the plant luxuriates in 

 soils abounding in vegetable matter, (2) that large stalks 

 count for good prices, (3) that the early puUings are in 

 most demand, (4) that the crop of any given year de- 

 pends largely upon the care of the plants the preceding year. 



Stable manure is especially valuable, because it sup- 

 plies humus, conserves moisture and furnishes plant 

 food. Some of the intensive and most successful growers 

 use 25 or more tons to the acre. Manure is probably 

 most effective when applied in the fall, although spring 

 dressings are often made. 



The commercial fertilizer should contain 4 to 6 per 

 cent of nitrogen and 8 to 10 per cent each of the mineral 

 elements. About 1,000 pounds an acre should be incor- 

 porated with the soil at the first cultivation in the early 

 spring. Nitrate of soda is of great value when used at 

 intervals throughout the growing season. Its use at the 

 close of the harvesting season is advocated to develop 

 strong roots for the next year's crop. The same princi- 

 ple is involved as in the fertilizing of asparagus. With 

 proper care plantations will produce for many years. A 

 mistake is made, however, by retaining them after the 

 stalks become materially smaller. It is doubtful if the 

 best profits can be realized in plantings more than five 

 years of age. 



589. Cultivation. — Thorough tillage throughout the 

 season is highly important. Enormous amounts of water 

 are used by the large leaves and succulent stems, and 

 conservation of moisture is urgent. At the first opera- 

 tion in the spring the mulch of manure is worked into 

 the soil. Subsequent tillage should be frequent, but not 

 too deep. Some hand hoeing is generally necessary to 

 keep the fields free from weeds. The seed stalks which 

 generally appear on a small percentage of the plants 

 should be broken off. 



