Amends the Federal Insecticide, Fungicide, and Rodenticide Act to add and clarify definitions for plant regulators, plant biostimulants, nutritional chemicals, and vitamin hormone products, and requires the Environmental Protection Agency to update its implementing rules within 120 days. Directs the Department of Agriculture to carry out a funded study on plant biostimulants to identify which types and uses best improve soil health and related outcomes, publish results, and report findings to congressional agriculture committees within two years after study funds are first made available.