Growing degree days · base 50°F

Growing degree days in Grand Rapids, MI

Season to date · since January 1

2,931GDD

Peak accumulated heat

The season has banked substantial heat. Warm-season grass is at its strongest; cool-season grass may be under heat stress and should not be pushed with nitrogen.

How the heat has built this year. Each day adds the average of that day’s high and low, minus a 50°F base, with nothing added on days that stay below it.Through 2026-10-12 · Open-Meteo archive

This week in Grand Rapids

Grand Rapids, MI added 77 growing degree days this past week, 11 a day, reaching 2,931 for the season. Its warmest day added 17.

Daily growing degree day accumulation in Grand Rapids, MI 49501 for the past week, base 50°F
Day	Added	Season total
Tue	5	2,859
Wed	14	2,873
Thu	7	2,880
Fri	6	2,886
Sat	16	2,902
Sun	12	2,914
Mon	17	2,931

PGR reapplication tracking

Plant growth regulator timing uses a Celsius-scale accumulation, not the seasonal Fahrenheit one. This page tracks a 10°C base, which is the Bermuda (warm-season) figure. Trinexapac-ethyl is typically re-sprayed near 200 GDD on cool-season turf and roughly 216 to 230 on warm-season turf, measured from your last application rather than from January. Always follow the product label.

Track GDD from your own spray date →

Soil temperature right now in Grand Rapids, MI

GDD is a trend indicator. Soil temperature is the signal that actually decides pre-emergent and seeding timing, and it is 61.8°F here at 2 inches.

Full soil report for 49501 →

Nearby

Growing degree days near Grand Rapids

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This page recalculates when you load it. The app accumulates GDD for Grand Rapids, MI daily and tells you when your PGR window opens. Free on iPhone and Android.