This season’s corn crop maturity is variable within field and between fields. Silking and tasseling in not uniform across most fields. You can see corn from knee high to early ear development in the first week of August. Targeting harvest will require planning. It will help to look at where we stand with growing degree days (GDDs) compared to the corn plant’s requirement for maturation.
Table 1. Growing Degree Day Accumulation in 2019 for Freeville, NY
|
Month |
Monthly Total |
Season Cumulative Total |
Average Daily Accumulation by Month |
|
May |
194 |
– |
6.0 |
|
June |
375 |
569 |
12.5 |
|
July |
642 |
1211 |
21.0 |
Table 2. Approximate Growing Degree Day Accumulation for Corn Development Stage in NY
|
Growth Stage |
80 day Hybrid |
110 day Hybrid |
|
Emergence |
110 |
110 |
|
Silk Stage |
1100 |
1400 |
|
½ Milk Line |
1800 |
2400 |
|
Maturity (black layer) |
1900 |
2500 |
How many more growing degree days are we likely to accumulate before a killing frost?
Using the data from the Freeville site, if our killing frost is October 15 historical records show a low of 2170 for the 30 year average accumulation to 2193 for the 15 year average accumulation. So let’s compare some dates for the killing frost in Table 3. To estimate whether your corn will mature before the killing frost compare the required GDDs for ½ milk line or black layer to long term records of season long accumulation.
Table 3. A comparison of Growing Degree Days for a series of first frost dates
| Date of First Frost – 320F | 30 yr Avg. GDD Accumulation | 15 yr Avg. GDD Accumulation | Cumulative GDD Lowest Year on Record | Cumulative GGD Highest Year on Record |
| Sept. 17* | 2024 | 2014 | 1718 | 2387 |
| Sept. 30 | 2117 | 2123 | 1802 | 2421 |
| Oct. 5 | 2142 | 2148 | 1814 | 2477 |
| Oct. 10 | 2163 | 2176 | 1824 | 2500 |
| Oct. 15 | 2177 | 2193 | 1832 | 2507 |
| Oct. 29** | 2200 | 2215 | 1846 | 2573 |
| *Earliest killing frost on record for the Freeville site | ||||
| **Latest killing frost on record for the Freeville site | ||||
This data was put together using the Cornell Climate Smart Farming Site and the Growing Degree Day Calculator. http://climatesmartfarming.org/tools/csf-growing-degree-day-calculator
The CSF Growing Degree Day Calculator can be a useful tool for predicting whether a late planted corn crop has a chance of maturing or not. If it unlikely to mature you can make an alternative plan to harvest and preserve your corn crop as fodder. To get to the tool go to http://climatesmartfarming.org and select the Growing Degree Day Calculator. There are video tutorials or you can jump right in with the edit button and typing in an address for a field location. Save the location or pointer. Move the pointer arrow to different dates along the x axis and a table will show potential GDD accumulation. You will also see last spring frost and first fall frost dates. Please contact Janice if you would like assistance using the Calculator.
