GDU Calculator — Growing Degree Units
Table of contents
What is GDU? Growing degree units definitionHow to calculate GDU for corn? Growing degree units for corn calulationThe importance of GDUsFAQsUtilizing our GDU calculator, we aim to help you assess the accumulated heat units required for optimal crop growth. To understand more on this topic, check out our corn yield calculatorand plant population calculator.
This tool is designed to enhance your comprehension of:
 What growing degree units (GDU) are;
 How to calculate GDUs for corn; and
 Their significance in monitoring crop development.
We'll also include examples to elucidate the process of calculating GDUs.
What is GDU? Growing degree units definition
Growing Degree Units (GDU), also known as Growing Degree Days (GDD), are a measure of heat accumulation used by agronomists and farmers to predict the growth stages of crops and plants.
GDUs quantify the amount of heat available over a growing season, helping to optimize planting schedules, manage crop growth, and plan harvests. This measurement is crucial for understanding crop development, ensuring they reach maturity within the growing season, and enhancing overall crop management.
How to calculate GDU for corn? Growing degree units for corn calulation
To understand how the growing degree units for corn calculation works, let's explore this with a hypothetical scenario:
 Base temperature: 10 °C
 Daily maximum temperature: 25 °C
 Daily minimum temperature: 15 °C

Determine the base temperature.
The first step is to determine the base temperature for the corn. This is the minimum temperature below which corn growth does not occur. For this example, we will use a base temperature of 10 °C.
Please feel free to use our mixed air temperature calculator to understand more about this topic.

Compute the daily maximum temperature.
Next, you need to compute the daily maximum temperature. For our scenario, the highest temperature of the day is 25 °C.

Compute the daily minimum temperature.
Then, you will need to calculate the minimum temperature for the day. In our example, the lowest temperature is 15 °C.

Calculating the GDUs for corn.
The last step is to compute the GDUs using the following formula:
In the formula, $T_{\rm max}$ is the daily maximum temperature, $T_{\rm min}$ is the daily minimum temperature, and $T_{\rm base}$ is the base temperature.
For our example:
GDU = (25 °C + 15 °C) / 2  10 °C} = 10 °C
Thus, the GDU for the day is 10 °C.
The importance of GDUs
Now that we have gone through the calculation of GDU, let's understand the importance of the GDU in agriculture.

Predicting crop development stages
As GDU can help estimate the different growth stages of crops, the metric can help farmers predict the development stage and make the right decisions based on it. For instance, if the crop is flowering, the farmers may decide to fertilize it.

Optimizing planting schedules
Plants grow best when the temperature is optimal. GDU can help farmers plan the best planting dates for their crops so that they will get the optimal temperatures at the right development stages, producing better crop yields.

Adapting to region climates
Different regions and places have different climates and weather. Using GDU, farmers can analyze which regions or even microclimates are best suited for their crops.

Protecting crops from adverse conditions
GDU can also help farmers protect crops from adverse conditions by allowing them to plan and prepare the crops in anticipation of any adverse conditions. This can help to reduce crop failure and financial loss.
How do I calculate GDU for corn?
You can calculate the GDU for corn in four steps:

Determine the base temperature.

Measure the maximum daily temperature.

Measure the minimum daily temperature.

Apply the GDU formula:
GDU = (max temperature + min temperature) / 2  base temperature
.
How many GDUs does corn need to emerge?
Corn typically needs 100 to 120 GDUs for optimal growth, which can usually be achieved 4 to 5 days after planting under favorable conditions.
What is the base temperature?
The base temperature is the minimum temperature below which crop growth does not occur. It is specific to each crop and is essential for accurately calculating GDUs.
How do GDUs affect planting schedules?
By understanding the heat accumulation required for different crops, farmers can determine the best planting dates to ensure that crops reach maturity within the growing season. This minimizes the risk of crop damage from early frosts or lateseason heat and optimizes crop yields.