SOIL STERILIZATION J . J ' ' j 



cent a cubic foot, provided the formalin was bought in 

 barrel lots at wholesale prices. A later circular (No. 151) 

 of the Ohio station places the cost of material for only 

 one house of 3,000 square feet at $21. This is much above 

 the required expenditure for steam sterilization as 

 estimated by the same station, viz., by perforated pipe 

 method $15.40 for 3,000 square feet, and inverted pan 

 method $12.20 for 3,000 square feet. A prominent Cleve- 

 land grower, who has about four acres of glass, states 

 that two men with four pans will sterilize 3,000 square 

 feet in two days, the labor costing $8, and fuel $6, or $14 

 for this area. An account was kept in a well-managed 

 house at Irondequoit, N. Y., where perforated pipes were 

 used, and the actual cost in a 30 by 180 foot house 5,400 

 square feet of space was $22.50. 



Hot Water Sterilization 



This method of sterilization has been attracting atten- 

 tion for several years. Waid, in a recent issue of the 

 Market Growers' Journal, writes as follows on this subject : 



"Recent accumulative evidence has demonstrated the value of 

 hot water as a treatment for greenhouse soil, especially when the 

 soil is infested with nematodes. To be effective, however, it is nec- 

 essary that it be forced into the soil to a considerable depth, 6 or 8 

 inches, and at a very high temperature. A grower at Grand Rapids, 

 Mich., used hot water on most of his greenhouse soil this season 

 with very satisfactory results. He heated the water in one boiler, 

 then forced it into a second boiler in which the water was kept 

 at a temperature of 238 to 240 degrees, under a pressure of 15 

 pounds. It required two days for five men to treat one house 275 

 by 34 feet. About five tons of soft coal was consumed per house. 

 The total cost of treating one house was about $50. One bed of the 

 same size was treated with $100 worth of formaldehyde. The hot 

 water treated beds gave the best and heaviest crops. The soil was 

 a light sand. It would seem that so much water might 'puddle* a 

 heavy soil." 



Tompson, in the same issue of the Market Growers' 



