How to use a corn moisture to harvest your corn at just the right time
July 26, 2024
Fall can be an anxious time for any corn grower. You want to get the crop off before the weather turns. But is that corn ready to go? Are you looking at significant drying charges that will eat into your bottom line? If you wait too long, are you risking lodging or ear drop? Don’t play a guessing game with your valuable crop. Follow these guidelines to get your corn moisture measurement just right.
Understanding maturity in your late stage corn crop
If you have a lot of experience at growing corn, chances are that you can recognize when that crop is ready for harvest. But just to be sure, let’s dig into the science of corn’s life cycle. As your corn crop matures, the sucrose entering the kernel falls below a certain level. Eventually, the plant develops a black layer that prevents any more sucrose from entering the kernel. Once that black layer is formed, grain moisture is typically at about 30%, although that can vary depending on the hybrid. That’s when you should start your corn moisture calculation.
Aim for less than 30% moisture
As harvest approaches, you want to get that corn down below 30% moisture. The ideal moisture level is considered to be 23-25%. If the corn is drier than that, you may risk losing grain during harvest, ear drop or lodging. If conditions are favorable such as warm, dry temperatures and windy, the corn will dry out readily. On a warm, breezy day in September, you can expect to lose up to one percentage point of moisture. Of course, fall weather doesn’t always turn out that way. Keep in mind that corn that matures in September is more likely to dry down better than corn that matures in October. Corn that matures in November will not dry down much at all in the field. Stalk and ear integrity will begin to deteriorate.
How to measure corn moisture
Once your crop has reached the full black layer stage, you’ll need a reliable method of calculating moisture. 2
Walk into the middle of a field where the corn looks driest and kernels are dented.
Grab 2 or 3 ears from your selected stand
Most modern moisture testers like the popular GAC 2700-AGRI from Dickey-John feature touchscreen control and fast results, regardless of grain temperature.
Remember this simple rule of thumb: the drier the corn, the lower the test weight. Most modern corn moisture meters will list the test weight and the moisture level.
Get ready for harvest
Now that you’ve accurately assessed moisture levels in your corn crop, you can confidently begin harvest. Depending on whether you plan to sell the crop immediately or store it on-farm, you’ll know whether the crop requires additional drying or if it’s dry enough to store safely at the moisture level you recorded from your field samples.
