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.
They say that April showers, bring May flowers - but what will the predicted snow later this week bring, at least in the northern portion of the buckeye state? Only time will tell!
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 March 31, 2024
Ohio City (County)
Zip Code
GDD Unit Accumulation
Bryan (Williams)
43506
112
Toledo (Lucas)
43615
110
Sandusky (Erie)
44870
108
Elyria (Lorain)
44035
106
Cleveland (Cuyahoga)
44120
101
Burton (Geauga)
44021
97
Jefferson (Ashtabula)
44047
93
Van Wert (Van Wert)
45891
112
Findlay (Hancock)
45840
110
Medina (Medina)
44256
105
Mt. Gilead (Morrow)
43338
115
Mt. Vernon (Knox)
43050
133
Steubenville (Jefferson)
43952
130
Dayton (Montgomery)
45417
150
Springfield (Clark)
45505
150
Columbus (Franklin)
43210
159
Lancaster (Fairfield)
43130
160
Marietta (Washington)
45750
170
Cincinnati (Hamilton)
45223
168
Hillsboro (Highland)
45133
172
Ironton (Lawrence)
45638
174
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.
Additionally, once you are at the website, you can click on summary, and it will provide you the yearly GDDs and the 20 year average. To illustrate that, I have done this with the zip code at my office (43615) in Toledo, Ohio using March 31 as the common date.
Date: March 31
GDD Unit Accumulation
2024
110
2023
52
2022
83
2021
95
2020
46
2019
28
2018
47
2017
115
2016
114
2015
10
2014
9
2013
32
2012
237
2011
23
2010
56
2009
82
2008
36
2007
86
2006
50
2005
35
2004
57
20 Year GDD Average for Toledo (43615) on March 31 - 65 GDD Units
More Information
The Ohio State Phenology Calendar Website
https://weather.cfaes.osu.edu/gdd/