Biostimulants: Helping crops beat stress and boost yield

Biostimulants are rapidly emerging as an essential tool for South African farmers, helping crops withstand variable environmental conditions while making the most of available nutrients to deliver stronger yields – even in challenging seasons.

Venessa Moodley from Omnia shared insights at a recent Grain SA research meeting that brought together researchers, industry partners, policymakers and producers to exchange ideas and explore how stronger collaboration can support innovation and long-term growth in the grain sector.

Moodley highlighted the role of biostimulants and emphasised how closer cooperation between science, industry and policy helps unlock their potential for farmers.

What are biostimulants?

According to a research article in Science Direct, “A plant biostimulant is any substance or microorganism applied to plants with the aim to enhance nutrition efficiency, abiotic stress tolerance and/or crop quality traits, regardless of its nutrient content.”

Moodley explains, “Biostimulants are the bridge between input, stress, and yield. They don’t directly deliver nutrients, but they help plants cope with stress and make the most of the nutrients they have.”

She adds that some biostimulants even include humic and fulvic acids, protein extracts, seaweed extracts, and beneficial microbes.

Why biostimulants matter

The market for biostimulants is growing worldwide, driven by demand for sustainably produced food. According to Spherical Insights, the global biostimulants market is expected to surpass USD 9.8 billion by 2032, growing at an annual rate of 11.1% from 2022. This rapid growth is driven by the push for more sustainable farming practices and the rising demand for high-quality crops.

She also points out that affordability and integration into existing application systems are the main factors holding back adoption, especially in grains. In addition, she notes that the lengthy regulatory approval processes and the need for feasibility studies make it harder for farmers to access new products.

Biostimulants support plants during stress by helping maintain normal metabolic processes that would otherwise reduce yield and crop quality. Photo: Pexels

How biostimulants work

“When a plant is stressed, it redirects energy away from growth and yield toward survival. Biostimulants can help plants maintain growth and quality even under tough conditions,” Moodley explains.

For example, trials with a microbial product showed that under severe drought, treated plants produced the same root biomass as unstressed plants. “This is a clear demonstration of how science-backed products help farmers manage plant stress in the field.”

She notes that understanding how these products work enables the development of practical solutions that are effectively applied under real farm conditions.

Practical tips for farmers

Moodley offers advice for getting the most from biostimulants:

Know your soil and crop needs – “A holistic view of soil chemistry, biology, and physics is essential to identify what is limiting your crop’s growth,” she says.
Timing is critical – Moodley emphasises that timing remains critical, particularly in drought-prone regions. Under these conditions, biostimulants must be applied at the appropriate stage of crop development to perform effectively, even when water availability is limited.
Delivery matters – Most biostimulants are applied as liquids, although in some regions farmers may prefer dry formats that are easier to integrate with fertiliser applications.
Integrate into your programme – “Biostimulants are most effective when they are part of an overall crop management plan, not used in isolation,” she says.

The future of biostimulants

Moodley explains how biostimulant products have evolved, moving through three distinct generations.

The first generation consisted of products with undefined compositions and inconsistent results, offering limited impact on crop performance. The second generation marked a step forward, with well-defined formulations supported by research and clear claims. This allowed farmers to see more predictable benefits.

Today, the focus is on third-generation biostimulants, which are fully understood at a mechanistic level and designed as integrated solutions that address specific farm challenges.

“Biostimulants are no longer a nice-to-have,” Moodley says. “They are a practical tool for modern farmers to manage stress, improve yields, and grow crops sustainably.”