30 PRACTICAL CORN CULTURE 
weather is on the road it is sometimes advisable to start plant- 
ing even if the ground is a little cold, in order to finish before 
the season is too far advanced. At the Illinois Experiment 
Station at Urbana (latitude forty degrees), a six year ’s test 
shows the largest yield to come from corn planted May 4th to 
9th. 
Proper DrepTtH oF PLANTING 
The depth of planting, like the time of planting, is governed 
to a considerable extent by the nature of the soil and the 
amount of moisture near the surface. On warm, light soil, 
corn should be planted deeper than where it is cold and heavy. 
Again, the depth of planting will be governed largely by the 
time of planting. In early planting, only the surface soil is 
warm enough to germinate the kernels. The subsoil is still 
wet and cold. Later, when the surface soil has become 
warmer and dryer, the seed may be planted deeper. 
In planting corn, the fact must be kept in mind that for 
quick germination plenty of air and warmth are just as 
essential as moisture. Nine years out of ten there is enough 
moisture in the soil to sprout the corn, although the season 
of 1913 was an exception. It was then necessary to plant 
about four inches deep in Central Illinois in order to provide 
sufficient moisture. While we planted over four inches deep 
the season mentioned, we used furrow openers on the planter 
runners so that by throwing out a furrow it was not necessary 
to cover the seed with more than two inches of dirt. We 
always use furrow openers on our planters and vary the 
depth of the furrow according to the condition of the ground, 
but in no case do we cover the seed with more than two 
inches of dirt. About one and one-half inches over the seed 
seems to bring the best results on our brown silt prairie soil. 
Repeated experiments have proved that plants cannot 
be made to send their roots deep into the soil by planting deep. 
