Are there good alternatives to peat?

There are substitutes for peat, but so far, replacing its excellent physical, chemical, and biological properties has proven challenging. Peat regenerates very slowly, making sustainable production dependent on new solutions.

“The results from the SUBTECH project show that several plant species can be cultivated in mixes where the range of the peat replaced with other alternatives was from 25 to 100 %,” says project leader Dr Anita Sønsteby at NIBIO.

This applies to strawberries grown in plastic tunnels, as well as certain flowers and herbs. However, not all crops react the same way. A common factor for all is that when peat is removed from the growing medium, fertilization and irrigation must be adjusted for each plant species.

“The challenge with most types of compost is that quality, including structure and nutrient content, varies significantly,” explains Dr Trond Haraldsen at NIBIO.

Several producers of growing media have attempted to introduce peat-free, compost-based blends of growing media for both private gardens and professional use. However, according to Haraldsen, none of these products have reached significant volumes in the market so far.

Wood fiber, such as Fibergrow® produced by Hunton, appears to be a promising alternative. It is a locally sourced, uniform raw material of Norway spruce fibers. Tests show that wood fiber can replace peat in blends, and in some cases—such as for cucumbers and tomatoes—pure wood fiber can yield better results than rockwool.

The SUBTECH project concluded with a seminar at Gardermoen in February, where representatives from research, industry, and the growing media sector shared their experiences. The follow-up project, SUBTECH 2.0, will run until 2027 to further develop knowledge and ensure stable plant production without peat.