With the large acreage of late-planted corn this year, the probability for some of that crop experiencing a frost or, worse yet, a hard freeze before it’s mature is much higher than in a normal growing season.

A frosted, immature crop is the trickiest of all corn silage harvest scenarios because it often looks drier than it really is. Larry Chase, an extension dairy nutritionist with Cornell University, recently offered the following tips if you are faced with a situation where the crop shuts down before it reaches optimum maturity and harvest moisture:

• The leaves will quickly turn brown and the plant will appear “dry.” This gives a false reading on whole-plant dry matter (DM) since the leaves are only 10 to 15 percent of the total plant weight on a DM basis. Most of the plant moisture is in the ear and stalk.

• Whole plant DM needs to be determined to assess when to harvest. Ensure the crop is over 32 percent DM before starting harvest.

• Frost may kill some of the normal bacteria on the plant. A research-proven inoculant is often effective in getting a good fermentation started.

• Harvest as quickly as possible once the crop hits optimum whole-plant moisture. This lowers the risk of the plant getting too dry and the potential for mold growth on the ear. The risk for mycotoxins rises when corn plants are subjected to stress.


• Try to store immature and normal corn silage in separate facilities. This provides for better flexibility at feeding time and allocation to specific animal groups.

• Make sure you have enough packing tractor weight. The rule of thumb is 800 pounds of packing tractor weight for each ton of silage delivered per hour. If the filling rate is 100 tons per hour, you would need 80,000 pounds of packing tractor.

• Pack in thin layers (5 to 7 inches).

• Consider covering the silo walls with plastic on the inside to minimize air infiltration through cracks and joints.

• Seal the silo with plastic and tires or a low-oxygen permeability cover.