Field Crop Update September 11, 2026

Silage season is beginning! I don't have much to add this week except another plug for our upcoming corn silage dry-down events. DESPITE the abundance of red in the growing degree day chart in section 2, indicating lots of heat since silking, and thus great conditions for corn development, many corn silage crops still need some more time before they're ready. So if you're unsure of how close your corn may be to peak maturity, stop out at one of our events over the next few weeks:

We will be hosting THREE corn silage dry-down events in September. Bring your samples and get whole-plant dry matter, starch, and estimated harvest date range:

1. Sept 11 - Keystone Mills, Fort Plain: 682 Fordsbush Rd, Fort Plain (518-527-6838)
2. Sept 16 - Cornell Cooperative Extension of Madison County: 100 Eaton St, Morrisville (315-684-3001)
3. Sept 21 - Lutz Feed Co: 80 Lower River St, Oneonta (607-432-7984) 

• All dry-down events 10am - 1pm. No registration required. Free.
• Cut a bundle of 3-4 stalks from each field at the height you plan to set the chopper
• Samples should be cut on the morning of the event

See: Climate Smart Farming Growing Degree Day Calculator

Growing degree days (GDD) are calculated by taking the average daily temperature and subtracting the base temperature for development of a given organism ((High + Low)/2 – base temp = GDD).

For corn, we use base 50/86, as corn development starts at 50 degrees F and ceases above 86F. Check your location and planting date for grain GDD.

For silage, we track GDD from silking. Silking in our region began mid-July and is continuing through the first half of August. Your crop may have tasseled on or more closely to one of these dates. So while our GDD tables can get you in the ballpark, check your own whole-plant DM to make sure you’re ready, and not ahead/behind schedule!

Remember: Silage corn needs 750-800 GDD (depending on hybrid maturity) after silking to reach a whole plant DM of 32%. Under typical late season dry down conditions we can expect the crop to reach 35% DM four to seven days later. We can expect to accumulate 15-25 GDD per day, or even up to 30, so peak maturity can creep up on us quickly. But no matter what the numbers say, always check your crop to see how close you may be to harvest. For more details, see this article.

Silking date / silage forecast GDD color key (BALLPARK ONLY - these are based on corn development from silking at GDD (which is the best sight-unseen forecasting method we have, but still has limitations):

Blue: Time to make plans (32-35% DM anywhere between 5 – 11 days from now, depending on maturity)

Green: Gas up the harvester and the trucks (32-35% DM in 2 – 8 days, depending on maturity)

Yellow: See you in the field soon (32-35% DM imminently)

Red: It’s either already in the bunk or it’s eventually going for high-moisture corn or grain (DM likely closer to 40%)