58 MASS. EXPERIMENT STATION BULLETIN 327 



methods. 



Further work is necessary to determine what practical propagation methods 

 and control measures are most feasible for growers. 



Study of the Effect of Plant Nutrients, Soil Reaction, and Light on 

 Gardenias. (Harold E. White, Waltham.) Gardenias produced more 

 flowers per plant under sand plot culture conditions than in soil, irrespective of 

 different levels of nitrogen, phosphorus, and potash. The highest yield per 

 plant in the sand plots was 16 flowers as compared to 10 flowers per plant in 

 soil. When different ratios of nitrogen, phosphorus, and potash were used, 

 there was greater variation in yield between individual soil plots than between 

 sand plots in the same series. Increasing nitrogen, phosphorus or potash did 

 not produce any significant differences in yield. 



There was considerable variation in the amount of bud drop in both sand 

 and soil, but in no case was there complete freedom from bud drop under any 

 treatment. The summary of data on bud drop is as follows: 



Bud Drop, Percent 



Low High 

 Nitrogen Series: 



Sand 19.31 56.37 



Soil 55.84 78.37 



Phosphorus Series: 



Sand 16.50 34.67 



Soil 24.75 71.11 



Potash Series: 



Sand 19.31 51.08 



Soil 37.00 90.00 



Interveinal chlorosis was very severe on plants in all soil plots which were 

 given calcium nitrate and sodium nitrate as sources of nitrogen and in plots on 

 which one-half of the nitrogen was supplied as calcium nitrate in combination 

 with ammonium sulfate. One soil plot receiving all of its nitrogen from an 

 organic source showed only a trace of chlorosis, while another which was fed 

 with a fertilizer containing sulfur showed no chlorosis. Plots receiving ammo- 

 nium sulfate as a source of nitrogen did not show chlorosis. 



Plants grown in sand and fed with calcium or sodium nitrate as a source of 

 nitrogen showed severe chlorosis; whereas, when one-half the nitrogen was 

 supplied as ammonium sulfate, the chlorosis was reduced to a noticeable degree. 

 Direct inoculation of chlorotic leaves with various chemicals resulted in a re- 

 sponse when iron compounds only were used. Plants severely affected with 

 chlorosis did not recover when applications of iron sulfate, sulfur, or ammonium 

 sulfate were made to the soil around such plants. Chlorotic plants placed in 

 soil where all other plants were normal did not recover their green color after 

 an elapse of five months. 



Soil pH would not seem to merit the importance that has been attached to it 

 as an indicator for determining the best cultural conditions for gardenias. This 

 may possibly be found to hold true for all those plants classed as having a 

 preference for an acid soil condition. The average pH, taken over a period of 

 six months, varied from 5.0 to 6.0, with chlorosis appearing on plants when 

 the pH at times dropped below 5.0. 



Lengthening the day by six hours with 60-watt bulbs, starting in November 



