GROWING VEGETABLES UNDER GLASS. 193 



subject to injury b}- both insects and fungous diseases than those 

 in healthy growth. 



A good crop of both lettuce and cucumbers is usually grown in 

 a new greenhouse the first year, but the succeeding crops are far 

 more subject to disease. This suggests the importance of the 

 system of rotation of crops, where it is possible to adopt it, in 

 order to avoid the spores of fungi, which rapidly accuipulate in the 

 soil and surroundings where repeated crops of the same vegetable 

 are grown. This is not always easy to accomplish, the great 

 demand for forced lettuce obliging the gardener to repeat this crop 

 often. 



Discussion. 



Benjamin M. Watson, Jr., inquired concerning the arrangement 

 of pipes for heating. 



Mr. Philbrick replied that, under the impression that cucumbers 

 and lettuce required bottom heat, the pipes were at first placed under 

 the beds. Three objections to that arrangement were soon mani- 

 fest ; first, that the pipes dried the soil too quickly ; second, that 

 the pipes so placed failed to heat the air in the house sufficiently ; 

 and third, that the benches soon decayed. Therefore it w^as de- 

 cided that the pipes must be either in the alleys or overhead, 

 and the beds ])uilt upon the ground. 



Mr. Philbrick added that certain vegetables can be grown 

 together successfully, but he prefers to grow only one kind at a 

 time in one house. Amateur gardeners, however, often wish to 

 grow several vegetables together. Dandelions Avill thrive in a tem- 

 perature of 40° at night ; lettuce from 45° to 50°. Yet dandelions, 

 lettuce, and radishes can be grow^n together easily. Cucumbers 

 require more heat ; still, in their younger stages of growth, rad- 

 ishes or beets may be grown with them ; but when the}^ begin to 

 bear fruit they demand so much more heat, as well as more room, 

 that radishes cannot succeed. Tomatoes, like cucumbers, must 

 have a high temperature. In growing strawberries and cucum- 

 bers under glass, one great difficulty is in fertilizing the flowers. 

 If bees are about the premises they will perform this work for 

 cucumbers, but otherwise hand-fertilization will be imperative. 

 Lettuce will head when the temperature runs up to 80° in the sun- 

 shine ; but high temperature at night must be guarded against. 

 Lettuce is also liable to be burned at 80° temperature in the day- 

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