Phoenix, AZ / Bermudagrass Turf

Total GDD: 9664 (Nov 30)

Day 303 / 303 (100%)

Total GDD: 9664 (Nov 30)

Method: 50°F

7-Day Daily Avg: 12.1

7-Day Projection: 9749 by Dec 07

Season: Feb 01, 25 - Nov 30, 2025

Last Freeze:
10%: 01-02
50%: 01-09
90%: 01-25

First Freeze:
10%: 12-24
50%: 12-28
90%: 12-30

Growing Degree Days (GDD) track heat accumulation to predict when plants reach growth stages, pests emerge, and diseases become active.

Thresholds mark specific GDD values when events typically occur, with crossing dates showing when your season reaches each milestone.

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PGR Program Start 500 °D

Mar 5, 2025 | Mar 13, 2024 | Mar 27, 2023 | Mar 17, 2022

Growth Stage

Full green-up. Begin Primo Maxx applications at 200 GDD intervals.

Peak Growth Period 2000 °D

May 10, 2025 | May 16, 2024 | May 23, 2023 | May 13, 2022

Growth Stage

Maximum clipping yield. Shorten intervals to 7-10 days. Scout for bermudagrass mites.

Summer Stress Window 4500 °D

Jul 9, 2025 | Jul 10, 2024 | Jul 19, 2023 | Jul 11, 2022

Growth Stage

Monitor for PGR phytotoxicity. Reduce rates on drought-stressed fairways and roughs.

Fall Transition 7500 °D

Sep 11, 2025 | Sep 10, 2024 | Sep 20, 2023 | Sep 17, 2022

Growth Stage

Overseed preparation begins. Final PGR before scalping and verticutting.

PGR Program End 9000 °D

Oct 27, 2025 | Oct 15, 2024 | Nov 6, 2023 | Nov 11, 2022

Growth Stage

Discontinue applications. Allow carbohydrate storage before winter dormancy.