Do farmers make a random guess as to when to plant corn? NO! There’s a whole lot of science behind knowing when to plant corn, when to expect different stages of growth, and when to harvest – it’s called growing degree days (GDD). This activity requires some mathematical calculations to find out when is the optimum time to plant corn.
Take a look at the table below labeled, Growing Degree Days: An A”maize”ing Harvest Calculation. As you can see the temperature plays an important part in the growth of healthy corn. The formula for calculating the GDD is as follows. We are using F for Fahrenheit in this activity.
There are two rules to follow:
Example: If on a beautiful May day, the high (maximum temperature) was 80°F and the low (minimum temperature) was 56°F, then:
The average temperature for the day is = (80°F + 56°F) divided by / 2 = 68°F And that day’s Corn GDD (°F) = 68°F – 50°F (this is the lower base temperature) = 18 GDD (°F)
Answer key to worksheets found in PDF.
Summary question. Most corn varieties require 100 GDDs to emerge. Based on your calculations would the corn in this example accumulate enough GDDs to emerge? Yes
This lesson is the work product of the Kansas Corn Commission. Our lessons are written in collaboration with Kansas teachers for use in the classroom. Teachers may copy and share this curriculum. Use of this product for commercial or promotional use is prohibited without express permission of Kansas Corn.
As the need to produce more food with less resources grows, it is important that future generations have a better understanding of agriculture and how corn farming and agriculture fit into our daily lives. That’s why the Kansas Corn STEM program provides lessons to teach science through the lens of corn. We are committed to providing free materials and training to support educators.
