In the first study, researchers tested how incorporating wood fiber into the lower layers of containers affects plant growth. They found that using coarse wood fiber below and finer, more moisture-holding material on top helped roots develop well while keeping seedlings healthy and vigorous. The approach also offers flexibility for growers to tailor substrate mixes to specific crops or growing conditions.
A companion study confirmed that layering low-peat and peat-rich materials within the same container can significantly reduce overall peat use. Plants grown in these stratified mixes performed just as well-or even better-than those grown in traditional uniform substrates.
A third study reinforces these findings-showing that stratified systems can cut total peat use while maintaining or improving seedling quality compared to traditional uniform mixes.
Together, these findings give growers practical tools to cut peat use, manage costs, and move toward more sustainable production, all while maintaining the high-quality plants their customers expect.
Collectively, these findings offer practical strategies for nurseries and growers seeking to produce high-quality plants sustainably. By combining stratified substrates, careful packing, and peat alternatives, growers can reduce peat dependency, improve root architecture, and enhance production efficiency.
These studies represent a step forward in sustainable horticulture, demonstrating that environmentally responsible substrate management can go hand-in-hand with high-performance plant production.
According to Dr. Fields, "Researchers across the world have been searching for peat alternatives for decades, but the answer might lie in managing the way we use the substrates we have. Through stratification, we can effectively reduce peat-use by 50% without sacrificing plant growth or quality. Substrate stratification also allows the use of low-cost or recycled materials in place of peat and other growing media, supporting continued and sustainable growth of the horticultural industry."
Dr. Fields is Assistant Professor of Nursery Production and Environmental Horticulture at the University of Florida. His extension & research program is focused on developing more efficient and effective production practices through his environmental nursery production lab. Dr. Fields' primary interests include soilless substrate science, irrigation & fertilizer management, whole plant-water relations and plant abiotic stress physiology.
The full article can be read on the ASHS HortTech electronic Journal website at: https://doi.org/10.21273/HORTTECH05570-24 and https://doi.org/10.21273/HORTTECH05660-25 and https://doi.org/10.21273/HORTTECH05683-25
Established in 1903, the American Society for Horticultural Science is recognized around the world as one of the most respected and influential professional societies for horticultural scientists. ASHS is committed to promoting and encouraging national and international interest in scientific research and education in all branches of horticulture.
Comprised of thousands of members worldwide, ASHS represents a broad cross-section of the horticultural community-scientists, educators, students, landscape and turf managers, government, extension agents and industry professionals. ASHS members focus on practices and problems in horticulture: breeding, propagation, production and management, harvesting, handling and storage, processing, marketing and use of horticultural plants and products. To learn more, visit ashs.org.
