BULLETIN No. 466 



SPRAYING LAWNS WITH IRON SULFATE TO 

 ERADICATE DANDELIONS. 



M. T. MUXN. 



SUMMARY. 



Experiments made at the Station during the past eight years 

 demonstrate that dandelions may be eradicated from lawns, at rela- 

 tively slight expense and without material injury to the grass, by 

 proper spraying with an iron sulfate solution. Ordinarily, four or 

 five applications are required. The first spraying should be made in 

 May just before the first blooming period. One or two others 

 should follow at intervals of three or four weeks; and, finally, one 

 or two more in late summer or fall. During the hot, dry weather of 

 mid-summer spraying should be discontinued because of the danger 

 of injury to the grass. A conspicuous blackening of the lawn which 

 follows each application soon disappears if the grass is growing 

 vigorously. Of the other common lawn weeds, some are killed while 

 others are but slightly injured by the spraying. Unfortunately, 

 white clover, also, is killed. Spraying should be supplemented by 

 the use of fertilizers and the application of grass seed in the spring 

 and fall of each year. With proper management it is necessary to 

 spray only about every third year in order to keep a lawn practically 

 free from dandelions. 



The cutting-out method of fighting dandelions is laborious and 

 ineffective unless the greater part of the root is removed. Shallow 

 cutting, unless done frequently, is worse than none at all, because 

 each cut-off root promptly sends up one or more new plants. 



Tests of certain after-treatment measures in the form of reseeding, 

 liming of the soil, and fertilization with commercial fertilizers and 

 stable manure, used in conjunction with the spraying operations, 

 gave results which serve highly to recommend their use either 

 singly or in combination on lawns. 



A study of seed production in the common dandelion shows it to 

 be partheno genetic, that is, capable of producing viable seeds with- 

 out fertilization of the ovules by pollen. 



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