464 EXPERIMENT STATION RECORD. 



acid gas has proved most satisfactory when properly used. The best conditions, as 

 found in the authors' experiments, are absolute darkness, still air, temperature 

 below 60° F., and a dry house. Under these conditions it has been possible to keep 

 down the white fly by fumigating once each month with 1 oz. of cyanid of potassium, 

 2 oz. of sulphuric acid, and 4 oz. of water to each 1,000 cu. ft. of house space. When 

 fumigations were made in daylight with larger amounts of cyanid there was con- 

 siderable injury to the foliage of tomatoes and severe injury to the foliage of chrys- 

 anthemums, geraniums, and begonias. 



The time required for forcing a crop of melons is placed at approximately 6 months, 

 and the cost of a full crop is about $1 per melon. The English types of melons have 

 been found to give the best results in forcing. 



Notes are given on the beginning of the cucumber forcing industry in New England 

 by Dr. J. Fisher, and on commercial methods of growing cucumbers in .Massachu- 

 setts by G. M. Kendall, from which it appears that the best soil in which to force 

 cucumbers is a sandy loan mixed with about one-third fresh horse manure. The 

 vine is trained up to about 10 ft. and nipped off. Each lateral is also nipped off at 

 the first joint beyond the cucumber. White Spine is the variety chiefly grown. 

 The temperature of the house should be about 65° at night and 90° to 100° on good 

 sunshiny days. 



At the station, the authors have grown chiefly the long English type of cucumber. 

 This type is grown in shaded houses, as the large succulent leaves burn if exposed 

 to full sunlight. General directions are given for their culture and care in the 

 greenhouse. 



Soil treatment in greenhouse culture, H. J. WhBeler and G. E. Adams 

 (Rhode Inland St< a. Bid. 107. />]>. L',7-167).— An experiment was made to determine 

 the initial and residual effects of stable manure and different kinds of commercial 

 fertilizers when used for different greenhouse crops. 



In the test 1,400 lbs. of subsoil was used in each of 4 sections. The soil was first 

 treated with lime to correct acidity. Section 1 was then fertilized with horse manure 

 at the rate of 75 tons per acre. Sections 2, 3, and 4 were given identical amounts of 

 potash, phosphoric acid, magnesia, and nitrogen in different commercial forms. 

 On section 2 such chemicals were used as would not be likely to leave any injurious 

 residues in the soil. 



On section 3 potash was applied in the form of muriate instead of nitrate, as in 

 section 2, and sulphate of ammonia was used as a source of part of the nitrogen 

 applied. Both these sections received in addition mixed timothy and redtop hay 

 cut in lengths of half an inch to an inch and thoroughly incorporated in the soil. 

 Section 4 was treated exactly like section 2 except that no chaffed hay was used. 



The first crop grown was radishes. The manured section led all the others in 

 yield and size, 1,400.6 gm., sections 2, 3, and 4 following in regular order, the latter 

 yielding only 952.2 gm. Section 2 yielded nearly as well as the manured section, 

 1,376.7 gm. 



A second crop of radishes was then grown after additional fertilizers had been 

 added. The smallest yield with this second crop was on section 1, where stable 

 manure was used, and the largest on section 2, where care had been taken to avoid 

 chemicals which might leave toxic residues in the soil. 



This crop was then followed by tomatoes on half of each section and cucumbers on 

 the other half. The largest total yield of tomatoes, 11,852 gm., was obtained on 

 section 3, showing that the residuals of the chemicals used had no toxic effect for 

 this crop. The yield of cucumbers on the manured section was nil, due to lack of 

 nitrogen, caused by denitrification processes which were especially favored by the 

 use of such large amounts of manure under the favorable conditions afforded by the 

 greenhouse. 



