66 Gardening 



Compost may be made also from the vegetable wastes 

 of the kitchen that decay readily, from weeds, grass 

 clippings from the lawn, leaves in autumn, and other 

 vegetable matter of any kind. These should all be 

 saved and composted either with manure or separately. 

 Good compost is very valuable in forcing and growing 

 transplanted seedlings in flats in greenhouses, hotbeds, 

 and cold frames, as well as for enriching the soil of the 

 garden. 1 Every garden should have a compost pile. 

 Care should be taken not to add to compost diseased or 

 insect-infested plants, for this may facilitate the spread 

 of fungous diseases or insect pests. 



Commercial fertilizers. A commercial fertilizer fur- 

 nishes for the use o^plants nitrogen, phosphorus, and 

 potassium. Nitrogen is usually obtained in sodium 

 nitrate, ammonium sulfate, and in " tankage " (the 

 refuse of slaughterhouses). Phosphorus is usually ob- 

 tained from tankage and from acid phosphate, which 

 is made by treating rock containing phosphates with 

 sulfuric acid. Potassium is obtained mostly from potas- 

 sium sulfate and potassium chlorid, both of which are 

 mined from the earth. 



A fertilizer that supplies all of the three elements, 

 nitrogen, phosphorus, and potassium, is called a " com- 

 plete " or " general " fertilizer ; one that supplies only 

 one or two of these is called an " incomplete " or " spe- 

 cial " fertilizer. 



A good general fertilizer for garden crops should 

 contain in a form that plants can use, by guaranteed 



1 Compost should not be used for seed beds or in seed pans, as it is 

 too rich for young seedlings. 



