57 



their roses. They make a practice of using soil composted with cow 

 manure which is allowed to remain out over winter. There is no 

 doubt that owing to this method of preparing the soil they are able 

 to keep nematodes in check. 



Cost of Sterilization. 



The expense of sterilizing the soil will largely depend upon one's 

 equipment and the conditions under which it has to be done. If one 

 has a large steam boiler which he uses for heating his houses, then 

 the necessary expenses involved would not be very great. The 

 expense of purchasing tile, or steam pipe if one happens to use 

 such, which in the latter instance w^ould have to be drilled and 

 connected, would be the heaviest to bear. We prefer tile to steam 

 pipe and think they are fully as effective, and then again they can 

 be used for subirrigation purposes, a practice which according to 

 those who have experimented with it gives beneficial results. On 

 the other hand if one had to purchase a steam boiler together with 

 the tile the first expense might be of some account. The 2 in. tile, 

 however, cost about one cent each, or purchased in quantities some- 

 what less, and are slightly over one foot in length, and a second hand 

 steam boiler* of 6 or 8 horse power giving a pressure of steam equal 

 to 40 or 80 lbs. can be purchased for about $50 or $60, and would 

 answer the purpose for most greenhouse growers. Larger boilers 

 would be better as they carry m.ore water, a necessary feature in 

 this kind of work, inasmuch as there is considerable water used up 

 in heating owing to the condensation of the steam. The soil in a 

 bench 12 in. deep, 15 in. wide, and 80 ft. long, or in other words 

 100 cu. ft. of soil, in which were placed two lengths of tile 2 or 3 in. 

 from the bottom, could be easily heated in one and one-half to two 

 hours time. The tile in such a bed we will say costs $1.75 and the 

 extra expense for coal would be vmimportant. Some further idea of 

 the expense of heating the soil can be obtained from the amount of 

 soil employed and the time required to heat it to 212° F. as ascer- 

 tained by Galloway and others. According to Galloway he suc- 

 ceeded in heating about 72 cu. ft. of earth in two hours time. 

 Lodder's beds evidently contained 480 cu. ft. of soil which he heated 

 in three hours, while Rudd's beds contained 600 cu. ft. which he 



*In purchasing a second-hand boiler of high pressure it would be well to obtain the State 

 Inspector's certificate. 



