COLD VERSUS WARM WATER FOR PLANTS. 



IT is the generally accepted opinion of florists and gardeners that 

 watering plants with very cold water is detrimental to growth, 

 but no one has undertaken to state definitely how cold the water 



may be without producing this result. It is the common opinion, 

 however, that water applied to greenhouse plants should not be much 

 colder than the air immediately about them. In order to ascertain 

 the facts in the case more definitely the Wisconsin Experiment Sta- 

 tion instituted a series of tests. The plants were grown under glass, 

 except as otherwise noted. 



Twelve cuttings of Coleus, as nearly alike in size and vigor as 

 could be obtained, were divided into four lots and planted in sand. 

 They were watered with water at 35°, 50°, 65°, and 86° F. In twelve 

 days all were rooted equally well. They were potted off and the 

 watering continued. There was no noticeable difference in growth 

 and vigor between the various lots until sixty days after the cuttings 

 were taken, when the 86° lot was slightly the highest. This ad- 

 vantage was only temporary, however, for in a few days the 50° and 

 65° lots slightly exceeded it in height. Ninety days after the cuttings 

 were taken the 35° lot was plainly checked, but the other three were 

 practically equal. This test was repeated with water at 32°, 40°, 70°, 

 and 100° In this case it was difficult to discover any influence due to 

 the temperature of the water used. 



Transplanted tomato plants were divided into four lots and 

 watered with water at 35°, 50°, 65°, and 86°. The 65° lot made the 

 best growth throughout the test, which lasted for thirty days. The 

 35° lot made the slowest growth, but was in no other respect inferior 

 to the others. This test was repeated with water at 32°, 60°, and 90°. 

 After sixty days the 32° lot was slightly the best. The plants were 

 the tallest, ripened earliest, and the plants and fruit weighed the 

 most. This trial was repeated with plants from seed saved from the 

 fruits of the first crop. Plants from the 32° lot were watered with 

 water at 32°, those from the 60° lot were watered with water at 70°, 

 and those from the 90° with water at 100°. 



" In this case the 100° lot yielded the largest amount of fruit and 

 the 32° lot was next in order, while the 70° lot yielded the least; 

 but the difference is so slight that the results may be considered 

 duplicates." 



Beans watered with water at 32'', 40°, 70°, and 100° were equally 

 vigorous. Water at 32° and 40° gave the best results. Lettuce watered 

 with water at 32° yielded slightly more than other lots. 



