24 The: Colorado Experiment Station. 
it is best for the grower to take three or four men with him so that 
the work may be readily directed. This way of securing potatoes 
is somewhat more expensive, but experiments by Goff of Wisconsin, 
Waid of Ohio, and results in Germany, as well as in Colorado, show 
it to be time well spent. 
Buy Seed in the Fall. —It is a common practice for growers to 
defer buying seed till planting time in the spring. When this is 
done the grower ordinarily knows little if anything as to how these 
potatoes have been grown or stored. It would be better and cheaper 
if potatoes were secured at digging time so that the grower can 
know something of the growing and can make sure that these pota¬ 
toes have been stored in the best possible manner to retain their 
vitality. 
Storage of Seed. —There is an almost universal belief among 
growers that, if potatoes are chilled in storage, the vitality is de¬ 
creased, but no actual evidence is at hand to prove this theory. In 
fact, our experiments tend to the contrary. In all those districts 
where snow falls before the ground freezes and lies until late in 
the spring so as to prevent deep freezing of the ground, so-called 
volunteer potatoes that have lived in the ground over winter, come 
up in the old fields. Where potatoes are left in the ground over 
winter without freezing, it will be found that tubers are to all 
intents and purposes in the same condition as at digging time in 
the fall. In these cases the tuber, while not frozen, must remain 
at near freezing point during the whole winter season. The con¬ 
dition of storage that most closely approximates this condition must 
be best so far as vitality of the tuber is concerned. 
Sleeping Period. —Experiments have shown that the tubers 
must have a resting stage before they will grow. When mature 
potatoes are dug and immediately planted in the greenhouse, or 
southern grown potatoes are shipped to the north in the spring and 
planted, they will not grow till they have passed the resting period. 
The nearer dormant the tubers can be kept during the winter the 
better chance they have for making a perfect stand when planted 
in the spring. The danger from chilling is less than the danger to 
potatoes from heating. 
Heating. —This is the generation of sufficient heat in the pits 
or cellars to lower the vitality, and often follows freezing. Of 
course if the tuber is frozen so as to cause decomposition of the 
tissues, or frozen sufficiently to change the starch to sugar, the 
vitality will be impaired, even if the buds are not killed. 
Greening of Seed *—If the seed is kept dormant all winter 
*During the spring of 1908, a study was made at the Experiment 
Station of the effects of leaving seed tubers exposed to the light. Sev¬ 
eral sacks were spread for a month on the ground in a barn where the 
