Buckeye Yard and Garden onLine

GDD is a measure of the daily maximum and minimum temperature and directly relates to growth and development of plants and insects. The GDD of any zip code location in Ohio is estimated using the GDD of ten OARDC weather stations and available on the web at the site below.

The range of GDD accumulations in Ohio from north to south is 36 to 114. Following is a report of GDD for several locations around Ohio as of April 1, 2007: Painesville, 40; Cleveland, 40; Toledo, 36; Canfield, 41; Lima, 39; Wooster, 43; Coshocton, 49; Columbus, 58; Springfield, 51; Dayton, 56; Cincinnati, 84; Ironton, 103; Portsmouth, 104; and Piketon, 114.

To put these GDD accumulations into perspective, the following is an abbreviated listing of plant and insect species with their respective phenological event and average GDD accumulations at which these events occur. Due to variations in weather, temperature, humidity, etc., these events may occur a few days earlier or later than predicted by the average GDD. By looking at a city, town, or village near you from the above list, or visiting the above web site, you can see what could be taking place in the landscape around you.

Silver maple, first bloom, 34; corneliancherry dogwood, first bloom, 40; silver maple, full bloom, 42; red maple, first bloom, 44; northern lights forsythia, first bloom, 58; red maple, full bloom, 75; star magnolia, first bloom, 83; border forsythia, first bloom, 86; eastern tent caterpillar, egg hatch, 92; Manchu cherry, first bloom, 93; northern lights forsythia, full bloom, 94; Norway maple, first bloom, 116; border forsythia, full bloom, 116; chanticleer callery pear, first bloom, 123; sargent cherry, first bloom, 127; and larch casebearer, egg hatch, 128

For more information, see:

• Growing Degree Day and Phenology Calendar
• Understanding and Using Degree-Days