News » 29.01.2026 - Successful trials with peat-free Calluna and Poinsettia

Global demand for raw materials used in substrate production continues to grow, alongside increased attention to peat-free substrates with a higher share of renewable and circular raw materials. Van der Knaap Group has been working on this transition for several years.

Research into circular raw materials and peat-free substrates is carried out at the company's 'de Kas' innovation centre through an extensive trial programme. In addition, outdoor trials and a growing number of practical trials at customer sites are conducted.

Calluna
For the second consecutive year, trials aimed at reducing peat content in substrates were carried out at a large Calluna grower in Germany. Insights gained during the first trial allowed further optimisation of the substrate composition to better suit the crop.

The trials showed strong results. Calluna plants were successfully grown using a substrate with a 50 percent reduction in peat, a 75 percent reduction in peat, and a fully peat-free substrate. According to those involved, no visible differences were observed compared to plants grown on conventional substrates.

Poinsettia
Trials with Poinsettia were also conducted for the second time to assess the feasibility of peat-free cultivation without compromising quality. At research station Straelen, substrates with a 50 percent peat reduction and fully peat-free compositions were tested. The results were positive, with no differences observed in plant quality or shelf life when compared with substrates containing peat.

Local production and logistics
Substrates are produced at the company's site in Grubbenvorst (Limburg) using carefully selected raw materials. With local teams and available stock, deliveries can be organised efficiently. Multiple production locations allow for flexible responses to customer demand.

IPM Essen
During IPM Essen, visitors can view the results of the trials at the Van der Knaap Group stand. A new, circular raw material. This raw material has recently been granted an exemption and may be used in RHP-certified substrates in professional horticulture. Substrate solutions for crops such as soft fruit and perennials will also be showcased.
 

Source: www.floraldaily.com

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