66 VEGETABLE FORCING 
(10) It has some effect in binding sandy soils, but this 
function is of no practical value in relation to greenhouse 
soils, 
The yields of greenhouse crops are often materially 
increased by the application of lime, and every commer- 
cial grower should conduct simple experiments to 
determine its full value. It is improbable that any harm 
can result from the use of reasonable amounts. 
Commercial fertilizers.—As previously stated, commer- 
cial fertilizers are not used extensively by the market 
growers of vegetables under glass. In the chapters relat- 
ing to the various classes of vegetables, experiments will 
be cited in which fertilizers have been used advan- 
tageously. There is a strong impression among growers, 
however, that little if anything is to be gained by the use 
of chemicals, and the statement “that more harm than 
good has been done by the use of fertilizers in vegetable 
forcing” is very likely a truthful assertion. 
As early as 1892, Prof. W. J. Green of the Ohio station, 
after conducting some careful experiments, reported the 
following in Bulletin 48 of that station: 
“It may be urged that no results could reasonably be expected 
from the use of any fertilizing ingredient upon a soil already well 
supplied with plant food. The persistency with which the virtues 
of nitrate of soda for garden crops have been urged has led many 
to believe that it can be used with profit, even upon soils already 
full of fertility. 
“This experiment does not show that nitrate of soda, or any other 
fertilizer, cannot be used to advantage in any case, but rather that 
the limitations to their use are narrower than is commonly sup- 
posed. The soil used in this experiment was a clay loam. To fit 
such a soil for use in the greenhouse the best method is to compost 
it with stable manure, and such is the course generally followed by 
gardeners. The case would be different with a sandy soil, as the 
addition of stable manure, in order to make it friable and to prevent 
baking, is not so essential as with clay. Less stable manure would 
be needed with a sandy soil than with clay, and the deficiency in 
plant food could be made up with commercial fertilizers, and no 
doubt at a profit. A clay soil could be made friable by the addition 
