MAKING BEDS FOR SUB-IRRIGATION. 69 



advance of those of any other Station. He has contin- 

 ued these studies until the present time, and he and 

 his colleagues have published various reports of them. 

 Professor F. W. Rane has also made similar investiga- 

 tions at the West Virginia Experiment Station, the results 

 of which are published in Bulletin 33 of that Station.* 

 The entire subject is so important in its relation to the 

 forcing-house industries that I shall make copious extracts 

 from Mr. Green's last bulletin (No. 61, September, 1895) 

 upon the subject. 



Construction of beds and benches for sub-irrigation. 

 "A water-tight bed, or bench bottom, is necessary in sub- 

 irrigation, and there are several methods by which this 

 may be secured. Our first attempt was made with 

 matched lumber or flooring, the joints being filled with 

 white lead. The objection to this method of construction 

 is partly on account of the cost, but more particularly 

 because of the fact that when the boards swell the bot- 

 tom bulges upward, displacing the irrigating tile and caus- 

 ing leakage. It has been found that common barn boards, 

 or any rough lumber, answers better, if the cracks are bat- 

 tened with lath, and a layer of cement is spread over the 

 entire bottom, deep enough to almost cover the lath. 

 About one-third of good cement and two-thirds sand, 

 made quite thin with water, spread on to the depth of 

 about half an inch, and not allowed to dry too quickly, 

 answers the purpose very well. The bottom boards will 

 last longer than when the soil is placed directly upon 

 them, but the supports underneath need to be somewhat 

 nearer together than in the ordinary method of con- 

 struction, so as to prevent springing of the boards, which 

 cracks the cement. The greatest difficulty is found in 

 making the sides of the benches water-tight, as no matter 

 how well the side boards are nailed to the bottom boards, 



*Rane has also published an account of sub- irrigation in the open 

 in Bulletin 34 of the New Hampshire Experiment Station. 



