Plant Biostimulant Act of 2025

This bill creates a clear, national definition for “plant biostimulants,” so farmers and product makers know what counts and how these products are treated under federal pesticide law. It says plant biostimulants are substances or microbes that, when used on seeds, plants, soil, or growth media, help the plant’s natural processes—like improving nutrient use, handling heat or drought, and boosting growth or yield—separate from the product’s nutrient content . It also clarifies related terms like “nutritional chemical” and “vitamin hormone product,” and adjusts the definition of “plant regulator” so that qualifying plant biostimulants aren’t treated like traditional pesticides .

The Environmental Protection Agency must update its rules within 120 days after the law takes effect to reflect these definitions . The U.S. Department of Agriculture must study which plant biostimulants and practices best improve soil health—such as cutting runoff, raising organic matter, and helping with carbon storage—and publish a report within two years after funds are provided for the study .

• Who is affected: Farmers, ag retailers, product makers, EPA, USDA .
• What changes: Clear definitions for plant biostimulants; some products no longer treated as “plant regulators”; EPA must update regulations; USDA will run a soil health study and report results .
• When: EPA updates due within 120 days after enactment; USDA report due within two years after study funds are made available .