WATER-CULTURE METHOD — HOAGLAND AND ARNON 



485 



PREPARATION OF NUTRIENT SOLUTIONS*. METHOD A, FOR AMATEURS 



Either one of the solutions given in table 2 may be tried. Solution 2 

 may often be preferred because the ammonium salt delays the develop- 

 ment of undesirable alkalinity. The salts are added to the water, 

 preferably in the order given. 



To either of the solutions, add the elements iron, boron, manganese, 

 and in some cases zinc and copper. There is danger of toxic effect if 

 much greater quantities of these elements are added than those 

 indicated later in the text. Molybdenum and possibly other elements 

 required by plants in minute amounts will be furnished by impurities 

 in the nutrient salts or in the water, and need not be added deliberately. 



Table 2. — Corn-position of nutrient solutions. 1 {The amounts given are for 25 gallons 



of solution.) 



SOLUTION 1 > 



SOLUTION 2 



1 The University does not sell nor give away any salts for growing plants in water culture. Chemicals 

 may be purchased from local chemical supply houses, or possibly may be obtained through fertilizer dealers. 

 Some of the chemicals may be obtained from druggists. If purchased in fairly large lots, the present price of 

 the ingredients contained in 1 pound of a complete mixture of nutrient salts is approximately 5 to 10 cents for 

 either solution described above. 



» To either of these solutions, supplements of elements required in minute quantity must be added; 

 see directions in the text. 



(a) Boron and manganese solution. — Dissolve 3 teaspoons of pow- 

 dered boric acid and 1 teaspoon of chemically pure manganese chloride 

 (MnCl 2 .4 H 2 0) in a gallon of water. (Manganese sulphate could be 

 substituted for the chloride.) Dilute 1 part of this solution with 2 

 parts of water, by volume. Use a pint of the diluted solution for 

 each 25 gallons of nutrient solution. 



The elements in group 1 are added when the nutrient solution is 

 first prepared and at all subsequent changes of solution. If plants 

 develop symptoms characteristic of lack of manganese or boron, 

 solution a, in the amount indicated in the preceding paragraph, may 

 be added between changes of the nutrient solution or between addition 

 of salts needed in large quantities. 18 But care is needed, for injury 

 may easily be produced by adding too much of these elements. 



18 The University is not prepared to diagnose symptoms on samples of plant tissues sent in for examination; 



