What are Growing Degree Days?

Growing degree days (GDDs) are a measure of the heat that accumulates over a given period of time. They are calculated by taking the average temperature for each day and subtracting 50 degrees Fahrenheit. If the temperature is above 50 degrees, the GDDs for that day are positive.

GDDs are a useful tool for predicting when plants will start to grow and when insects will emerge from hibernation. They can also be used to track the progress of crops and to identify potential pests and diseases.

In Ohio, the growing season typically starts in April and ends in October. The GDDs for the growing season typically range from 1,000 to 2,000. However, the GDDs can vary depending on the year and the location in the state.

The amount of GDDs that a plant needs to germinate depends on the type of plant. Some plants, such as corn, need a lot of GDDs to germinate. Other plants, such as soybeans, need fewer GDDs.

Insects also use GDDs to track the progress of the growing season. Some insects, such as mosquitoes, emerge from hibernation when the GDDs reach a certain level. Other insects, such as moths, lay eggs when the GDDs reach a certain level.

GDDs are a valuable tool for farmers, gardeners, and scientists who study the environment. They can be used to predict when plants will start to grow, when insects will emerge, and when pests and diseases are likely to occur.

Here are some additional facts about GDDs:

• GDDs are a cumulative measure. This means that the GDDs for a given day are added to the GDDs for all the previous days.

• The GDDs for a given day can be calculated for any location. This means that GDDs can be used to track the progress of crops and insects in different parts of the state.

• GDDs are a useful tool for predicting the first and last frost dates. This information can be used to protect crops from damage.

• GDDs are also a useful tool for predicting the emergence of pests and diseases. This information can be used to take preventive measures to protect crops.

If you would like more information about Growing Degree Days, The Ohio State University has a site where you can enter your zip code and see your current GDD number. Click here to learn more!