Table 5. Yields of Tomatoes Grown in Pure Bari< Compared to Soil — Fertilizer Added 



Old Soft- 

 wood Bark 



Ave. yield of ripe fruits 



per plant (10 plants). 730.5 



Ave. weight of individual fruits 60.3 



Old Hard- 

 wood Bark 



494.2 

 62.5 



Soil Control 



315.5 



45.7 



trols, the one for the old softwood bark significantly so. The average size 

 of fruits was considerably greater for each bark culture than the control. 

 It appears from this that either one of the old barks makes an excellent 

 growing medium, if an adequate nutrient supply is maintained. 



Effect of Sewage Sludge on Growth of Plants in Bark 



This experiment was conducted to determine something of the modifying 

 effects of sewage sludge on bark as a growing medium. Sewage has been 

 used extensively in Europe as a composting aid for various materials (2) 

 and in composts with sawdust at this station (1). Two mixtures consisting 

 of different proportions of sewage to the two kinds of old bark were pre- 

 pared, namely, 1 to 5, and 1 to 8. No fertilizer was applied. Cabbage plants 

 were grown in ten containers (one plant per container) of each of these 

 mixtures in comparison to soil as a control. The yields are given in Table 

 6. The yield for each proportion of old hardwood bark to sewage is sig- 

 nificantly greater than that from the soil controls. The plants in old soft- 

 wood bark and sewage mixtures did not yield significantly greater than 

 the plants in soil only. 



Table 6. Dry Weight Yields of Cabbage (Tops) Grown in Bark-Sewage Mixtures and in Soil 



Treatments 



Mean Dry Wt. of 10 Plants 



1 part sewage — 8 parts old hardwood bark 



1 part sewage — 5 parts old hardwood bark 



1 part sewage — 8 parts old softwood bark 



1 part sewage — 5 parts old softwood bark 

 Soil — control 



13.9* 



11.6* 



7.2 



6.3 



5.6 



Mean of yields significantly greater than controls at the 5 percent level. 



Root Growth in Bark and Other Materials 



The greenhouse operator, nurseryman, and other plantsmen are frequently 

 concerned with growth of seedlings and getting a good start with them. It 

 seemed desirable to secure information on seedling root growth in bark 

 compared to other materials with which it might have to compete on the 

 market. 



The growth measurements of three kinds of seedlings, grown from seeds 

 planted directly in the medium, are presented in Table 7. New softwood 



