The cool and wet spring forced many farmers to plant their corn and soybeans later than normal. Some ponded areas were still being planted or replanted in late June. But after much stress getting started, the weather settled down and conditions became almost ideal for corn and soybeans. We are rapidly approaching the end our race to harvest. The focus is now on frost, will the crop reach maturity before the first frost?

Most of the time and energy of crop farming goes into getting healthy plants to maturity with as little stress as possible. This will hopefully give us maximum yield. How do we know when we have reached this point and can relax? Plant physiologists over the years have studied both corn and soybeans to determine what visible sign best corresponds with the point at which the plants have reached their maximum dry weight. Stress on the plant after this point will not affect yield.

In corn there are two indicators that are often used, kernel milk line and black layer. Break an ear in half and look at the cross section of the tip half of the ear. By watching this side of the kernel you can monitor the progression from juicy sweet corn stage kernels to the hard starchy grain that will come out of the combine. The starch solidifies at the end of the kernel away from the cob and you will see a white coloration shrinking towards the cob as it approaches maturity. Shortly after the milk line disappears the "black layer" forms. To see the black layer you pop a kernel off the ear and scrape or cut carefully at the tip of the kernel where it has been attached to the cob. Physiological maturity occurs between these two visible events. Kernel moisture averages about 30 percent at this point. Mature but too wet to safely store.

In soybeans the indicators are not quite as clear-cut. A soybean seed is mature when it loses its green color. The pod that the seed is in will lose its green color at about the same time. Unfortunately all the pods don't mature at exactly the same time. One recommendation is when most of the pods are no longer green. "Most" is not very precise so the more widely accepted indicator is when one pod on the main stem has reached its harvest color. This may be brown or gray depending upon the variety characteristics.

This is the point in the race where the runner puts on a final burst of speed, "kicks" into the finish line. Will the corn and soybean crops "kick" into harvest before Mother Nature kicks us with an early frost?