14 
Colorado Experiment Station 
toward the plants. Even this is unnecessary if the seed is planted 
deep enough to keep the growing tubers from pushing out of the 
soil. 
IRRIGATION 
The Horticultural Department is frequently called upon to 
give advice as to when and how potatoes should be irrigated. To 
answer such questions intelligently, a knowledge of soil conditions 
is absolutely necessary. Many growers believe that potatoes 
should not be irrigated until the vines are setting the 
tubers, even though the vines are actually suffering from 
lack of water. This riiay work out all right, but one may well 
question the wisdom of following such a rule. It is a universal 
rule that when a growing plant needs water and shows signs of 
wilting, water should be applied, so that the normal growth will 
not be checked. When the tubers have once set, it is necessary 
to irrigate so as to keep the soil in best growing condition possible 
for the balance of the season, or until the crop is matured. In 
other words, there should be no check to the growth of the plants 
after the tubers have once started to develop. If a check is given 
during this period, and the plant resumes its growth afterwards, 
knobby and gnarly tubers result. Hence the importance of keep¬ 
ing the young potatoes growing without check throughout the 
season. 
Second growth of tubers caused by improper irrigation 
In irrigating potatoes, it is much better to apply enough 
water thoroughly to saturate the ground, rather than small amounts 
of water at frequent intervals, as frequent applications of water 
will puddle and harden the soil to a much greater extent, and 
there is danger that some plants will not get enough water. A 
small stream running for a long period is better than a large 
stream for a short period. 
