74 



MANAGEMENT OF THE FORCING-HOUSE. 



periments are given. * * * No effort has been made 

 to select examples, further than to secure a fair average, 

 rather than to present the highest or the lowest. The 

 average gain of the sub-irrigated over the surface-watered 

 in the above cases was a little more than 40 per cent. 

 This increase in weight was made in a little more than 

 six weeks, or from the time the plants were set in the 

 benches to the end of the experiments. That is, all of 

 the plants were sub-irrigated while growing in the flats, 

 or during about half of their period of growth, and not un- 

 til they were planted in the benches was surface-watering 

 commenced. This is a less favorable showing for sub- 

 irrigation than is made in the last table, by the plan 

 above described, of carrying the plants through the entire 

 period of growth by the respective methods of watering. 



RESULTS IN FIFTEEN SUB-IRRIGATION EXPERIMENTS 

 WITH GRAND RAPIDS LETTUCE. 



"In the above examples, the surface- and sub-irrigated 

 plots were side by side, but a more satisfactory plan is to 



