The cost of storing corn in the crib on the farm is made up of three main items, shrink, interest and insurance, and destruction by vermin.
The biggest item of cost is the shrink, or loss of moisture. This amounts to about 10 percent.
This shrink, however, is offset or more than offset by the highest price received for the improved grade which results from the shrink.
Interest and insurance come to nearly half a cent a bushel a month. It costs half a cent a bushel, therefore, to store corn, if the loss by vermin, or the cost of a rat-proof crib, is not included. If it is included, the total cost of storing corn is a cent a bushel a month.
On the average, the price of corn rises from winter to summer· more than enough to cover this cost.
After big crops, the price of corn usually rises more than it docs after small crops. After small crops, the price of corn may not rise enough to cover the cost of storing.
It is advisable, then, to store corn after a big or average crop, but not after a crop 95 percent of average size, or smaller. This rule worked 21 times out of the last 23 years. If tho price of No. 3 yellow corn does not rise above say 90 cents at Chicago this winter, the chances are 11 to 1 that it will pay better to store corn until next summer than to sell it this winter.
Shepherd, G. S., "When Shall We Sell Our Corn?" (1929). Circular. Paper 113.