The Plant Phenology and Growing Degree Day (GDD) posts and impacts have been a Buckeye Yard and Garden onLine (BYGL) staple for years. GDD will continue to be an important part of the blog written to assist green industry professionals, Extension professionals, Extension volunteers, and people with a passion for plants and pests too.
We know that as temperatures warm, we will continue to accumulate growing degree day (GDD) units - and that is indeed we are seeing in February with our recent recording breaking warm weather.
Readers will continue to see those updates in the BYGL on a monthly basis, but there is no better way to track GDD and ultimately the plant blooms and insect activity on your own. Be sure to save this website ( https://weather.cfaes.osu.edu/gdd/default.asp ) as a favorite, and set those calendar reminders now to check the website regularly.
Here is a Growing Degree Day Refresher if GDD is new, or you need a little review!
GDD 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 actual temperature experienced by an organism is influenced by several factors. These factors affect growth and development. For instance, depending on the weather, an organism's temperature may be a few degrees more or less than that recorded. An organism may spend its time in the shade or under direct sunlight. The fertility and nutrient content of the soil directly affect the growth rate of plants and thereby indirectly influence insect growth rates. The presence of weeds and precipitation may indirectly influence development. Due to these factors and some other scientific considerations, a base temperature of 50 degrees Fahrenheit is considered acceptable for all plants and insects. (Source: OSU Plant Phenology Website)
The one thing that we do know is that the sequence of events – both plant and pest development – consistently occurs in the same order no matter the weather.
At the end of each month this calendar year, there will be a GDD Summary Alert Posted to BYGL. While today's post has some areas seeing zeros - it is the start of the calendar year – we will have to see if that is true. As you can see below, 21 Ohio locations (City, County, and Zip Code) have been chosen across the state and will continue to be used for the monthly updates.
GGD Chart, ending February 29, 2024
Ohio City (County)
Zip Code
GDD Unit Accumulation
Bryan (Williams)
43506
37
Toledo (Lucas)
43615
36
Sandusky (Erie)
44870
35
Elyria (Lorain)
44035
35
Cleveland (Cuyahoga)
44120
33
Burton (Geauga)
44021
32
Jefferson (Ashtabula)
44047
30
Van Wert (Van Wert)
45891
37
Findlay (Hancock)
45840
36
Medina (Medina)
44256
36
Mt. Gilead (Morrow)
43338
39
Mt. Vernon (Knox)
43050
45
Steubenville (Jefferson)
43952
47
Dayton (Montgomery)
45417
45
Springfield (Clark)
45505
45
Columbus (Franklin)
43210
52
Lancaster (Fairfield)
43130
54
Marietta (Washington)
45750
63
Cincinnati (Hamilton)
45223
61
Hillsboro (Highland)
45133
65
Ironton (Lawrence)
45638
65
Not seeing your city or zip code? No worries! You can always check out the website, type in your Ohio zip code, and ground truth what you are seeing with what the calendar says should be occurring.