Sources
Research pages prioritize university extension publications, turfgrass programs, and pesticide safety education resources. Claims are kept narrow and tied to the cited source.
Soil temperature
Soil temperature is used as a timing signal for crabgrass prevention, warm-season green-up, and some disease-risk decisions. It is not a substitute for the product label, site conditions, or local extension advice.
Growing degree days
The GDD tool separates seasonal turf heat accumulation from PGR interval tracking. PGR timing uses a from-date model because Cornell’s turfgrass guidance explains that PGR suppression duration changes with temperature.
Labels and safety
Fertilizer, herbicide, fungicide, insecticide, and PGR recommendations are product-specific. The label determines legal and safe use. Tank mixes should follow label restrictions and compatibility guidance.