TOMATOES 275 



ing winter crops under glass, the question of substituting fertilizers for ma- 

 nure, in part at least, is a very important one. Forcing house soil as usually 

 prepared, consists of rich garden soil or rotted turf, composted with from 

 one-fourth to one-half its bulk of horse manure. Aside from the labor of 

 hauling and repeatedly working over this material to secure the fine mellow 

 condition which is desired, the cost formerly was not great. But the in- 

 troduction of electric cars enormously cut down the production of horse 

 manure in the cities, which has been the main dependence of our market 

 gardeners. In consequence, the preparation of suitable soil for forcing 

 houses is increasingly expensive. Besides this it is found that even a rich 

 natural soil cannot carry forcing house tomatoes to their highest productive- 

 ness, and therefore liquid manure is often used to water the soil after the 

 plants have come into bearing. The admirable work on the use of commercial 

 fertilizers on field tomatoes, done at the New Jersey Station, has proved that 

 the ripening of the crop may be very materially hastened by the proper use 

 of fertilizer chemicals, especially of nitrate of soda. 



To hasten the ripening of crops under glass, where the expense of growing 

 them is so much greater than in the field, must greatly increase the profits 

 of the business. A further question also connected with these, is, whether 

 the humus of rotted manure, generally regarded as necessary to regulate the 

 storage and circulation of moisture in the soil under natural conditions, can 

 be replaced by some cheap substitute, or dispensed with altogether in forcing- 

 house culture, where the supply of soil moisture can be well regulated by 

 artificial means. 



"Our first endeavor was to find out how much nitrogen tomato plants 

 raised under glass take from the soil, in their fruit and vines, and 

 how much nitrogen needs to be in the soil to meet fully this demand of the 

 plants. These questions we studied by raising tomatoes on the forcing- 

 house bench filled with soil known to be practically free from available nitro- 

 gen, but believed to contain all other ingredients necessary for a maximum 

 tomato crop. To these plats were added known quantities of nitrogen in the 

 form of nitrate of soda. The weight of the fruit harvested, and of the vines 

 which bore it, with the chemical analysis of both, furnish the means of deter- 

 mining how much nitrogen, phosphoric acid and potash a crop of tomatoes 

 takes from the soil. Comparison of the quantities of nitrogen applied to the 

 several plats, with the weights of the crops and of their nitrogen, gives some 

 indication of the amount of nitrogen necessary to apply in order to secure 

 a maximum crop." The house used in the experiments was specially con- 

 structed and was a three-quarter-span-roof house, 16x40 feet running east 

 and west, with a partition across the centre, making two apartments. The 



