734 



ELECTRO- HOR TICUL TURE. 



fluence of the light upon it. This benefit was fully as 

 apparent this year. There can no longer be any doubt 

 as to the advantage of the electric light in the forcing 

 of lettuce. The light was started October 19, i8gi. At 

 that time Boston Market lettuce four weeks old was set 

 on bench 4, and seedling plants of Landreth Forcing 

 were just showing on bench 3. The transplanted plants 

 (bench 4) in the light compartment soon began to excel 

 those in the dark compartment, and as early as October 

 27, or a week after the starling of the light, they were 

 perceptibly ahead of the others. In this time forty 

 hours of electric light had been expended upon the 

 plants. The plants directly under the light, from seven 

 to ten feet from the arc, were the first to improve. 

 November i the lighted plants were a fourth larger than 

 the others, and they showed a marked tendency to turn 

 toward the light. The plants, even to the farthest ex- 

 tremity of the light department, gained steadily through- 

 out the experiment, and were ready for market from a 

 week to ten days earlier than in the dark house. In 

 quality and all other characteristics this lettuce was dis- 

 tinguishable from that grown under normal conditions. 



The lettuce on bench 3, which had been sown there, 

 behaved differently. For the first week or ten days the 

 plants under the light were stunted, notwithstanding the 

 fact that they were farther from the lamp than those on 

 bench 4, which did so well from the first. After some 

 days of lingering, when the plants began to develop 

 three or four leaves, these seedlings began rapidly to 

 recuperate, and they finally overtook their companions 

 in the dark house ; but these plants never showed the 

 superiority which the transplanted ones on bench 4 ex- 

 hibited. We were prepared for this behaviour, for we 

 had observed it before, and Deherain has reported 

 similar results with other plants in his experiments in 

 Paris. The reason for this injury to very young plants 

 I shall not now attempt to discuss ; it is sufficient for 

 our present purpose to say that it appears to be better to 

 sow lettuce under common conditions, and when. the plants 

 are well established to transplant them under the light. 



Lettuce was also transplanted into the upper bench. 

 No. I, in order to determine how far the influence of 

 the light extends. The extremity of the light compart- 

 ment was forty feet distant from the lamp, and the roof 

 is so low that much of the light was reflected, yet at 

 this distance, where there was only diffused light, the 

 plants a month after the light started were much better 

 than those in the dark house. 



The experiment was repeated with second and third 

 crops of several varieties of lettuce with similar results. 

 February 9, Simpson lettuce was transplanted upon 

 bench 4, and the customary increase under the light 

 took place. March 22, when the lettuce was nearly 

 large enough for market, the light was transferred to 

 house B, and thereafter the poorer plants received the 

 light. These poorer plants soon showed the effect of 

 the new conditions, and the time between the maturity 

 of the two crops was considerably lessened. 



Perhaps the best illustration which we found of the 



influence of the light upon the lettuce was afforded by 

 a crop upon bench i, on which radishes were also 

 planted. The interception of the light by the radish- 

 leaves had a most marked effect upon the lettuce-plants 

 which stood behind them, the adjacent plants, which 

 chanced to be exposed to the full light being much 

 larger. The bench therefore presented a very uneven 

 appearance when the radishes were removed, and the 

 shadows from the radish-leaves could be traced in the 

 lettuce. Similar results were observed where the dense 

 shade of a rafter lay across the plants. 



As already told in the August number of American 

 Gardening, W. W. Rawson, of Arlington, near Boston, 

 now uses the electric light in the commercial forcing of 

 lettuce. Mr. Rawson calculates that he receives a gain of 

 five days in a crop of lettuce by the use of these lamps, 

 and, as he grows three crops during the winter, the total 

 gain is over two weeks of time. The gain from one crop 

 is estimated to pay the cost of running the lights all 

 winter. The effect of the light is said to be marked at 

 the distance of one hundred feet. 



Endive. — Plants of endive five weeks old were trans- 

 planted into bench 2 November ii. The plants in the 

 two compartments were much alike throughout the 

 experiment, and it is impossible to say if the light 

 exercised any beneficial influence, but it is certain tha 

 there was no injurious influence. In the 1890 test, under 

 the naked light, inside the house endive was injured, 

 but other plants which are known to be benefited by a 

 modified light also suffered under those conditions. 



Radishes. — Radishes of various kinds were grown 

 on benches i, 3 and 4, between young lettuce-plants. 

 The first crop — which alone is considered here— was 

 sown a week before the light started, so that the plants 

 were well up when the test began. Before the crop was 

 harvested, December 3, two hundred and twenty-nine 

 and one half hours of electric light had been expended 

 upon the plants, or an average of five and one-tenth 

 hours per night. 



The plants in the light house were best in every fea- 

 ture. The proportion of tops to the entire plant in this 

 house was greater than in the dark house, the difference 

 being that between 55 per cent, and 49 per cent. All 

 these results are interesting when compared with our 

 former experience, for they show how much the simple 

 interposition of plain glass may modify the influence of 

 the light. In 1890, under the naked light, radishes were 

 uniformly injured, the loss ranging from 45 to 65 per 

 cent. The same year, under a light protected by an opal 

 globe, the injury was still apparent, but the loss in tubers 

 was only from i to 5 per cent, of the crop, yet at the 

 same time the weight of leaves was increased. Now this 

 year, under light strained through a globe and a glass 

 roof, there was an increase of both tubers and tops. In 

 no case have radishes been sufficiently benefited to pay 

 the cost of the light ; but our results seem to show that 

 a well-protected light is some assistance to them. 



Beets. — Four days before the light started, October 15, 

 seeds of Early Egyptian beet were sown in both compart- 



