152 VEGETABLE FORCING 



sunshine, it may be unnecessary to water oftener than once 

 a week, or even at longer intervals under certain condi- 

 tions. On the other hand, in the summer it is usually 

 necessary to water every day and sometimes twice daily. 

 Whether it is summer or winter, much less water is re- 

 quired on cloudy days. 



It is always better to water when the temperature of 

 the greenhouse is rising rather than falling. Unless the 

 water is applied in a fine spray, it will make the soil 

 cooler, which, of course, is undesirable, but there need be 

 no anxiety about this matter if the temperature of the 

 houses, due to the rays of the sun or the heat from the 

 boiler, is gradually rising. Then, too, in order to prevent 

 injuries from various fungous diseases, the foliage of the 

 plants should be dry or free from excessive moisture 

 during the night. For the two reasons just given it is 

 preferable to water the beds in the forenoon, and that is 

 the general practice among greenhouse growers of vege- 

 tables and flowers. 



The pollination factor should also have consideration. 

 Pollination is most active when neither the atmosphere 

 of the house nor the plants themselves contain much 

 moisture. This matter should be watched closely in 

 tomato and cucumber houses, especially when there is 

 dull, cloudy weather. Under such conditions an abun- 

 dance of water should be used each time so that it will be 

 unnecessary to water more frequently than is absolutely 

 required. If the fruits are not setting well, it will be an 

 advantage sometimes to use less water than is actually 

 needed for the plants, in order to maintain lower 

 humidity, which is favorable to the pollination of the 

 flowers. 



If additional humidity is needed for any purpose, and 

 the beds should not be watered, the walks may be wet 

 down several times a day, if necessary. 



It will be seen from the foregoing remarks that no 



