FOECING-HOITSES FOE VEGETABLES, 261 



presenting themselves, very discouraging to those 

 who have ah-eady built this kind of house for forcing 

 vegetables. The greatest drawback is the damping 

 off of the plants in some parts of the beds. This oc- 

 curs at any stage of the growth, and without any ap- 

 parent cause. Sometimes when the Lettuce is half 

 or two-thirds grown, in certain spots, the plants look 

 wilted, the leaves droop, and they might just as well 

 be pulled out at once and thrown away, for they only 

 get worse the longer they remain. A friend, who is 

 largely engaged in this business, told me a short time 

 ago, that in one of his houses at least a third of the 

 crop was worthless from this cause, wliile in the other 

 two houses along side, planted and cared for in the 

 same way, there was not an injured specimen to be 

 found. In some cases the roots are rotted off, in 

 others the outside coating of the root seems loose and 

 comes off very readily, no insect marks of any kind 

 being discernible in either instance. Again, the 

 roots may be sound, but the leaves lose vigor and 

 droop when the sun shines. I am inclined to think 

 that this condition or disease is broiight about by 

 keeping the temperature of the houses above fifty 

 decrees with firelieat. 



The aphides, or " green fly," are very troublesome ; 

 if neglected they will soon get the better of the gar- 

 dener and destroy his crop of Lettuce in part or en- 

 tirely. They are very destruc^tive, and multiply at an 

 enormous rate. To guard against these little pests the 

 houses must be fumigated with Tobacco stem? tvnce a 

 week. For this purpose a number of sheet-iron fur- 

 naces, about fifteen inches high and eight in diameter, 

 12* 



