tains numerous weed seeds. If commercial fertilizers are used, of 

 course it is not necessary to add them first. 



Any small high-pressure boiler will serve to make the steam. 

 Some use a small independent boiler for the purpose; others attach 

 the apparatus to their high-pressure boiler. A low-pressure boiler is 

 usually unsatisfactory, as it takes a longer time to circulate the 

 steam ; it leaves the soil wet and soggy and does not do the work very 

 well. 



Soil sterilization is rapidly coming into favor for all intensive 

 work where the process is practicable. 



Three other methods of soil sterilization which have recently 

 come into use in commercial greenhouse work have several points in 

 their favor over the bin method described in this paper: (1) Steam 

 sterilization by means of drain tile laid in the bottom of the beds, 

 through which steam is passed; (2) also by means of an inverted 

 pan under which steam is admitted, and (3) sterilization by drench- 

 ing the soil with a formalin solution. 



In the tile method of steaming, lines of 2-inch to 3-inch glazed 

 tile are placed lengthwise in the beds to be sterilized, 2 to 2 1 /! feet 

 apart and 15 inches below the surface, and are left there permanently. 

 They provide drainage for the beds, may be used for subirrigation, 

 and are available at any time for sterilizing the soil, the only outlay 

 of labor being the covering of the beds with boards or a tarpaulin 

 and the connecting of the tile with a boiler by means of a piece of 

 steam hose. The soil need not be moved, and thus a large part of the 

 labor involved in sterilization is obviated. It is, however, advisable 

 to spade the soil up so that the steam may more readily penetrate it. 

 Another method of steaming by means of an inverted galvanized- 

 iron pan, 6 by 10 feet and 6 inches deep, under which steam is ad- 

 mitted, has been used to a more limited extent in the sterilization of 

 tobacco seed beds and also in greenhouse beds, and has given very 

 satisfactory results. The use of steam at a pressure of 80 to 100 

 pounds and treatment for from one-half hour to an hour after the 

 soil has reached a temperature of 100 C., as indicated by soil ther- 

 mometers, has given the best results. 



Formalin sterilization is accomplished by drenching the soil 

 with a 1 to 100 or 1 to 200 solution of formalin, at the rate of three- 

 fourths of a gallon per square foot of area, several days before the 

 soil is to be used. Formalin, however, does not rid the soil of ne- 

 matodes, as all the other methods do. This method has been used to 

 good advantage in the sterilization of lettuce beds for Rhizoctonia. 

 (Reprint Y. B. 1902, 1910 Ed.) 



Feeding Flowers with Commercial Fertilizers. While it is per- 

 haps safer to rely on organic or barnyard manures with bone and 

 wood ashes to supplement them in phosphoric acid and potash, 

 flowers can be grown without manures by the use of commercial 

 fertilizers. Commercial fertilizers where used in connection with 

 organic manures will first be considered. 



It is safest to use quick-acting and easily soluble fertilizers like 

 nitrate of soda, superphosphates, etc., in soils containing a good deal 



