SOIL STERILIZATION 101 
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 l/arket Growers’ 
