Biostimulants: How Can I Make Them Work for My Farm?

Maybe you’re not planning on using biostimulants in your production this season. But there’s a good chance that you’ve heard about biostimulants and wondered whether you should.

There’s a lot of information out there about these products, and perhaps just as many explanations about what they can do. Biostimulants don’t directly control insects or diseases. And while you may see some of them promoted as plant nutrition products, that isn’t technically correct either.

We wanted to cut through the confusion to help you understand what biostimulants are, how they work, and whether you should be investing resources in them this season.


So, we caught up with the Chair of BPIA’s Biostimulants Integration Committee, Terry Stone, Vice President, Regulatory Affairs for biostimulants supplier Agrinos, to ask a few questions and get a deeper explanation.

Q: So let’s clear things up. Broadly speaking, what are biostimulant products, and what do they do for plants and crops?
Stone: Biostimulants encompass a diversity of products that enhance the uptake of added or existing nutrients, nutrient efficiency, plant health, yield, and quality. They can enhance plant growth and development, improve the efficiency of plant nutrients as measured by either improved nutrient uptake or reduced nutrient losses to the environment, or both. They can also act as soil amendments, with demonstrated ability to help improve soil structure, function, or performance — and thus enhance plant response. Biostimulants can be derived from natural or biological sources such as bacterial or microbial inoculants, biochemical materials, amino acids, humic acids, fulvic acid, seaweed extract, and other similar materials. These products can improve soil health and agricultural sustainability.

Terry Stone of Agrinos

Terry Stone

Q: Are biostimulants fertilizer or plant nutrition products? Do they have any plant protection or pesticide properties?
Stone: Biostimulants are neither fertilizers nor pesticides. Rather, they uniquely facilitate the uptake of existing and applied nutrients, enhancing plant health and resistance to abiotic stress such as salinity or drought. They do not directly protect the crop from plant pests such as insects, disease, or weed competition.

Q: Are biostimulant products labeled and regulated like biopesticides are?
Stone: Biostimulants are regulated, but they are categorized as fertilizers or biopesticides depending on the claims a company makes for its products. This means developers are prohibited from calling their products biostimulants and limited in the benefit claims they can make. Companies must either register their product as a pesticide with EPA or as a fertilizer in every state they wish to market. Neither path is truly appropriate for these products, and both can be unnecessarily burdensome, costly, complex, and confusing for developers, regulators, and consumers.

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The biostimulant industry is actively working with EPA to issue guidance clarifying claims for plant regulators and products currently excluded from FIFRA such as fertilizers, soil amendments, and plant inoculants. Biostimulant products currently lack a specific regulatory path that would enable developers to register products according to their intended use, benefits, and safety. The industry is also actively working with the U.S. House and Senate agriculture committees on language for the next Farm Bill. Specifically, we are requesting biostimulants be defined (as described above) and that additional regulatory clarity be provided for the industry.

Q: How can growers or consultants determine when a biostimulant is needed for a crop?
Stone: Farming is a dynamic business where growing conditions change every year, and throughout the year. We have seen excellent results over a wide variety of conditions and specifically where growing conditions are variable, and perhaps not ideal, e.g., weathered soils, soils with poor nutrient holding capability, drought, etc. Biostimulants can be considered insurance to some degree, in that their use is helping to ensure yield stability in the event of a stress condition. The benefits will be realized over the course of the growing season and include improved plant health and vigor, resistance to abiotic stress, better quality, and ultimately improved yield.

Q: How can growers determine the efficacy of biostimulant products when they use them in their production?
Stone: One way is to ensure growers accurately measure the outcomes. It is also important to set up proper field scale trials to accurately monitor the benefits. Efficacy for biostimulants comes in different forms; the major types are increased yield and quality of the crops they produce. In addition, measuring root mass, soil consistency/tilth, crop color, and plant growth in harsher environments can be used to determine whether the product is working properly or not. In addition, sustainability measures include better N-utilization and a lower CO2 footprint in the target area of production.