Table 7. Comparative Tests of Root Growth in Bark and Other Materials 



and new hardwood bark were somewhat adverse to the growth of seedling 

 roots, mostly because they contained large pieces of bark which often blocked 

 the penetration of roots. Also it is difficult to compact such coarse materials 

 very much and roots are apt to dry out more readily in them. In general, 

 root growth was best in all in the old barks. The only other material of 

 those tried that compared favorably with the bark was fine vermiculite, 

 tested for two kinds of seeds only. 



Bark as a Rooting Medium for Cuttings 



There is a continuing search for new and better media for rooting cuttings 

 of various sorts. Since bark, especially the old materials, might offer possi- 

 bilities here, a trial was made of old bark in comparison to sand. Beds in 

 the basement at the greenhouse, furnished with fluorescent light, were pre- 

 pared with the materials listed in Table 8. Concord grape cuttings were 

 placed in them for over a month in early spring. The results on a limited 

 number of cuttings show that old softwood bark, either alone or mixed 

 with sand, has distinctly advantageous possibilities as a rooting medium. 



Table 8. Comparison of Bark Mixtures as Rooting Media for Grape Cuttings 

 Rooting Media Number Rooted Percent Rooted 



1/2 Old softwood bark, % sand 29 80 



Old softwood bark 25 69 



Sand 19 52 



V2 Old hardwood bark, V2 sand 18 50 



Geranium cuttings rooted well in the two old barks mixed with sand, in 

 comparison to sand alone. However, the roots broke off more easily in the 

 sand-bark mixtures. This difficulty probably could be overcome by judicious 

 watering. 



