Growing Degree
Days
SAMPLE
CHART
(See
Instructions Below)
| Date |
Soil Temperature |
Base Temperature |
TODAY'S |
TOTAL
|
| March 1 | 28 F |
33 F |
(-5) |
0 |
| March 2 | 33 F |
33 F |
0 |
0 |
| March 3 | 39 F |
33 F |
6 |
6 |
| March 4 | 42 F |
33 F |
9 |
15 |
| March 5 | 43 F |
33 F |
10 |
25 |
| March 6 | 45 F |
33 F |
12 |
37 |
| March 7 | 47 F |
33 F |
14 |
51 |
| March 8 | 38 F |
33 F |
5 |
|
| March 9 | 39 F |
33 F |
6 |
|
| March 10 | 36 F |
33 F |
3 |
|
| March 11 | 36 F |
33 F |
3 |
|
| March 12 | 39 F |
33 F |
6 |
|
| March 13 | 45 F |
33 F |
||
| March 14 | 43 F |
33 F |
- To calculate
"TODAY'S Growing Degree Day Units", subtract the base temperature
from the soil temperature:
- Soil Temp - Base Temp = Today's GDD
- Notice that the TOTAL Growing Degree Day units for March 1 is zero. This is because the soil temperature (28 F) is below the base temperature (33 F). (28 F- 33F = -5, so no heat is added.) That is, it was not warm enough on March 1 for any growth to occur.
- Growing Degree Days are cumulative. This means you add them up from day to day. In the sample chart: March 1 has zero. March 2 has zero. March 3 has six, March 4 has nine. We add all these days together and get TOTAL of 15 GDD as of March 4. We continue to add the amount of heat the plants receive each day. After 7 days they have received 51 Growing Degrees Day units.
- The sample chart is completed through March 7. Continue the following for practice:
For Practice:
- Fill in the TOTAL GDD values for March 8 -12. In total, how many growing degrees have accumulated by March 12? (68 units.)
- How many GDD units were added on March 13? March 14? (12 and 10 units.)
- In total, how many growing degrees have accumulated by March 14? (96 units)
