News » 29.08.2025 - Making progress with substrate slabs and jute plugs
This summer, a few greenhouses in the Netherlands are testing a new way of growing tomatoes, peppers, and eggplants: on organic substrate slabs made from jute. For Holland BioProducts, this is an important step into traditional greenhouse horticulture. Until now, the company has been most successful with jute-based substrates in hydroponics and vertical farming.
At the GreenTech Amsterdam trade show, Holland BioProducts presented its product range, which includes jute substrate slabs for greenhouse crops, jute pads for microgreens, and even jute plugs. "Right now, our main focus is hydroponics and vertical farming," says Sales Director Arjen de Haan, speaking from the company's office at the World Horti Center in Naaldwijk.
Holland BioProducts was founded in 2017 but brings more than fifteen years of experience in processing jute. With that expertise, the company develops high-quality, compostable alternatives to traditional substrates such as peat and rockwool. Their products are made from a specific part of the jute plant's fibers, sourced in Asia, combined with other raw materials from Europe.
Reinout Broekers, Rob Teepen, and Arjen de Haan (Holland BioProducts) at GreenTech Amsterdam 2025
Resilient cultivation
The jute plugs have a unique conical shape and a sowing slit, a product of the fact that they are designed for sowing and propagation in hydroponic systems. While they sometimes require slight adjustments to fit into existing setups, they are now widely used by large international customers, Arjen explains. Indoor farms in Switzerland, the UK, Scandinavia, the United States, the Middle East, and Australia are already growing successfully on Holland BioProducts' substrates.
For microgreen growers, Holland BioProducts offers the fully organic Blue Line Series, with jute pads that come in different thicknesses, tailored to the crop type and harvesting method, whether with or without roots.
The current movement toward more resilient cultivation is playing into the company's hands. In pepper production, as growers are increasingly shifting away from traditional substrates toward alternatives. For this market, Holland BioProducts has developed a substrate slab made with jute, blended with miscanthus and other grasses.
"It's really a mix of organic fibers," Arjen explains. "Jute provides strength, miscanthus adds airiness, and the grasses give volume. All components are sterilized to ensure a safe crop environment." The mats are suitable for more than just peppers, as tomatoes and eggplants can also be grown on them.
Collaborating with system manufacturers
Holland BioProducts has recently joined the World Horti Center as a participant and also became a member of Dutch Greenhouse Delta, a network that brings together many technical suppliers. "That's very valuable for us," says Arjen. "It connects us with system manufacturers Together we explore how their systems can be adapted so that growers can work successfully with our substrates."
Within Dutch Greenhouse Delta, the company has become active in the Middle East module. "We see strong growth there, just like in markets where the use of peat is under pressure, for example the UK. Scandinavia is another important region, where, just like in the Middle East, sustainability is a key driver."
Footprint
In order to measure its sustainability, Holland BioProducts had its substrates independently assessed by Wageningen University & Research. "The results showed that our substrates compare very favorably with other common options. Our footprint is significantly lower," Arjen confirms.
The numbers look very promising, especially for the slabs used in fruiting vegetables. "These slabs combine jute with grasses and miscanthus. Around 70 to 80 percent of the raw materials come from Europe, which helps keep the footprint low."
Holland BioProducts aims to be able to supply not only slabs, plugs, but also blocks made of jute, similar to ground plugs for soil cultivation and rock wool plugs and blocks for rock wool slabs.
Scaling with slabs
Holland BioProducts is making steady progress with its plugs and microgreen substrate, while continuing with new tests on substrate slabs for fruiting vegetables. Soon, they will meet with growers to review this season's results. "So far, the crops are growing well. Even during the recent heatwave, growers didn't need to add extra irrigation," says Arjen. Looking ahead to 2026, he expects that the Dutch four growers now testing the slabs will expand to using them on a larger scale, while other growers will begin with smaller trials.
Arjen explains that the early stages of cultivation require special attention., as growers cannot simply use the same methods they applied with their old substrates. However, as more crops are being tested, growers are starting to see the benefits of switching to alternative materials. One example is jute, which is fully compostable after use. "This saves growers money on disposal costs," Arjen says. Jute also has a lower environmental impact, needs less water to produce than coco, and is certified under the Fertilising Products Regulation (FPR).
Pre-seeded slab
To meet growing demand and improve local availability, Holland BioProducts is opening a new facility in the Middle East. Here, jute from India and Bangladesh will be sterilized and processed, improving logistics and efficiency. In the future, the company also plans to give large growers the option to produce plugs on site, helping them cut costs even further.
"But first, our priority is to make more growers aware of the possibilities of growing on jute," Arjen says. One eye-catching product that may help with that is the pre-seeded jute slab, which Holland BioProducts recently added to its range. These slabs are aimed at garden centers and other consumer-focused retailers, but to Arjen's surprise, there is also interest from professional growers. "That really wasn't something I expected," he admits with a smile.
Source: www.floradlaily.com
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