Growing Degree Days
I will start including Growing Degree Days (GDD) as part of the monthly vistas post. This is a good reference point for tracking plant and insect development.
“Growing Degree Days are a measurement of the growth and development of plants and insects during the growing season. Development does not occur at this time unless the temperature is above a minimum threshold value (base temperature). The base temperature varies for different organisms. It is determined through research and experimentation.” (The Ohio State Phenology Calendar glossary page)
We did a post on phenology last year. Check out the OSU Phenology Calendar to see what is happening in your area!
On March 10, 2025 when these images were taken, the growing degree days here was 29. For context, the 20 year GDD average for Delaware on this date is 40 and in recent years it has been:
- 2024: 86
- 2023: 99
- 2022: 48
- 2021: 26
Thus far, we are well behind on GDD but the week’s warm weather will certainly boost that number!
March Notes
- We did our major pruning of trees… primarily limbing up.
- Winter aconite, snow drops, and crocuses are blooming. These are non-native spring bulbs. We have not noticed these being a problem for the natives plants in the same beds. They have a lot of honey bee activity on them (it is too early for native bees).
Here is a comparison of how an area has come into bloom between February and March.
Upper Level (3.10.2025)
Swale (3.10.2025)
Southwest Corner (3.10.2025)
Southeast Corner (3.10.2025)
Video and photos by Randy Litchfield unless otherwise noted
© Randy Litchfield, some rights reserved (CC-BY-NC)
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