We're about at the end of the road as far as Mother Nature helping on drying corn down in the field. Besides, there's that elusive idea that corn loses actual weight and yield if it sits in the field too long anyway. It's likely time to work toward finishing harvest, but some corn planted late may still be at moisture levels that require drying.
How much flexibility you have in managing corn will depend upon the actual moisture content levels. Based on one farmer's policy, he sends corn that's above 17% through his continuous flow dryer, fueled by propane. Right now propane is about $2 per gallon in the Central Corn Belt. Relatively speaking, natural gas is a better buy if it's available to your grain operation.
If corn comes in at 17% moisture, he flips the handle on the diverter so corn goes to a large bin on the opposite side of the operation, instead of into the holding tank for the dryer. This bin is equipped with a large aeration fan that allows for drying. His goal is to remove the remaining points of moisture through aeration. When he can accomplish that, he saves energy charges, plus finds room for additional corn. His goal is to fill his storage facility before he stops to unload and haul corn off to make more room.
Drying corn in the bin takes a large fan. Fans on storage bins are often moving less than one cfm of air. That won't dry corn that is not dry already. The drying front moves through too slowly.
You also need to have as few broken kernels and fines as possible. One way to accomplish this is to set the combine so you're not putting lots of cracks into the grain cart or waiting semi truck. Fines tend to wind up in the middle of the bin and slow air flow. It's one reason why some people core a full bin, taking out enough corn to get the fines out of the center so that air will flow more evenly up through the grain mass.
The other option is to run corn through a grain cleaner to removes cracks and beeswings before the corn goes into the bin. In one operation the operator doesn't have a grain cleaner, but he does have a suction system to pull beeswings out of the dump and leg system, and deposit them into a holding tank on the ground outside the bins. It not only keeps finer material out of the center of the bin, but also makes the working environment at the grain center cleaner.Be sure you monitor corn once it's in the bin, especially if you bin it at 17% moisture, or dump hot out of the dryer at 17%, higher than the final moisture content you want for storage. Remember also that if you're checking corn coming out of the dryer hot for moisture, the real moisture a day or two later may be as much as a point or so higher. That's because temperature on the outside of the kernel can affect moisture readings.