Agronomy blog · March 21, 2025
What Is a Plant Growth Regulator in Row Crops?
A clear explanation of plant growth regulators in corn and other row crops—what they are meant to do and how farmers evaluate them.
PGR in plain terms
A plant growth regulator (PGR) is a product used to influence plant growth processes—such as height, lodging risk, or reproductive development—depending on the active and the crop. In corn conversations, growers often ask what a plant growth regulator does relative to fertility or fungicide passes.
PGRs are not fertilizers and not fungicides. They are tools with specific timing windows and label limits.
Where Midwest growers typically evaluate them
High-yield corn systems, irrigated acres, and fields with lodging history are common evaluation spots. Some programs also discuss late-season PGR timing around reproductive stages. Results depend on hybrid, weather, fertility, and whether the field actually had a lodging or canopy problem to solve.
Treat strip trials seriously: same hybrid, same fertility, documented timing, and harvest notes.
Questions to ask before you buy
Ask what growth process the product targets, which growth stages are labeled, what tank-mix partners are allowed, and what evidence exists in conditions like yours. Roush Ag Solutions can walk through plant growth regulator options and call-for-price availability for your acres.
Always verify rates, crops, tank-mix partners, and restrictions on the product label and SDS before you spray. This article is educational guidance for Midwest farmers—not a substitute for label directions or local agronomic advice.
Always verify rates, crops, tank-mix partners, and restrictions on the product label and SDS before you spray. This article is educational guidance for Midwest farmers—not a substitute for label directions or local agronomic advice.