64 PRACTICAL PLANT PROPAGATION 



THE ROOTING MEDIUM 



Coarse sand, free from all organic matter, * has proved to be the 

 best material to use in rooting cuttings. The sand furnishes good 

 aeration and drainage, but at the same time it allows for a free pas- 

 sage of water up from below. To eliminate danger from diseases 

 the sand is usually sterilized. An easy way to sterilize sand is to 

 load it into a metal wheelbarrow and take it into the boiler-room 

 where a pipe may be run from the boiler well into the center of the 

 load. Cover the sand with heavy carpet to retain the heat. Allow 

 steam to run into it for a half hour to one hour. (See also damping- 

 off fungus, page 65.) 



Fig. 18. A propagation house. The roof should be shaded. The benches are boarded 

 in below to retain the heat, an advantage in maintaining a higher temperature in the 

 sand than in the atmosphere. The sash-covered center benches ^ay be used for 

 propagating such plants as require a confined atmosphere. By building up the benches 

 and covering with glass, this house could be used for grafting Roses 



Before the cuttings are inserted the sand should be thoroughly 

 watered and tamped, or pounded hard with a wooden mallet or 

 brick. 



INSERTING CUTTINGS 



By means of a straightedge and a large, heavy knife, a groove 

 is cut into the sand. The cuttings are inserted and the sand packed 

 around them tightly. The commercial method is to place all the 

 cuttings in the rows first, then, with the fingers, compact the sand 

 about them. The straightedge is then placed along the rows and 

 several raps of the mallet serves to further set the cuttings firmly. 



* The presence of organic matter supplies a medium for the growth of injurious micro- 

 organisms; as Prof. O. F. Curtis points out, these organisms exhaust the oxygen in the 

 rooting medium, thereby weakening the cuttings. 



