At the North Brabant, Netherlands based Jongeleen Bell Pepper Nursery, Arie Jongeleen was puzzled by the root problems in his pepper cultivation for many days. The cause of that remained a mystery to him, until the switch to organic substrate made said root problems disappear. "The plants must need something organic," he says.
© Dutch Plantin BV
Excellent rock wool
Arie Jongeleen has forty years of experience in cultivation, with 22 of those years successfully using rock wool as a substrate. He says, "We always used new materials every year. Three years ago, we decided to reuse half of the materials to save costs. It worked for others, so why not for us? And it actually went quite well."
Last year, growing on the reused mats was positive, but root problems came up with the new mats - a widespread issue in the pepper space characterized by brown roots and weak plants. Following that, a sudden aphid infestation caused more issues for the grower. "It's an even bigger problem if plants are already weak, as crop protection solutions don't work as well." Tests did not reveal a clear cause. "A little pythium or fusarium always shows up, even in plants that are doing well. But in this case, things weren't going well. It started to keep me up at night."
Beautiful roots
The confusion is a complete contrast to how Arie feels now as he walks through the greenhouse. This year, he switched to growing green peppers of the Bastianini variety and red peppers of the Mathieu variety, both of which showed promising results in terms of production and quality during trials. "I just looked at the roots. I'm almost afraid to say it's going well, but they do look healthy, the way we want them to be."
Like many bell pepper growers, he switched to a substrate made of 100% coconut fiber from Dutch Plantin. "We also have a trial with a mix of coconut and peat. That's also a great mat, but bringing it into the greenhouse requires more effort. With 100% coconut, it's easier: you can take the pallet to the back and get started immediately. The Dutch Plantin mats are pre-drained, and the holes are in the right places. You can get to work right away."
Arie practices dry cultivation, an approach that works especially well with coconut substrate. "We water a bit later and stop a bit earlier. The amounts we give are slightly smaller, but there are no crazy issues. It's all quite manageable."
Mystery
The cause of the initial root problems that led Arie to use organic substrates remains a mystery. Even after consulting with other pepper growers and cultivation advisors, no clear cause has been identified. However, it's a fact that after the summer, the roots in Arie's garden grew better. "It's helpful because we didn't have to clear out any plants."
Last year's unusually wet weather has been ruled out as the cause of the problems. "This issue has been going on for four years. We've heard from growers whose entire greenhouses failed, except for the mats on organic substrate. But at the same time, there are growers with new rock wool mats who have no problems at all. Usually, people say, "The cleaner, the better," but since the plants thrived on reused mats, it seems they might benefit from something organic. However, we're not sure what that is. I don't think the cultivation methods have changed or that the rock wool is produced differently. We simply don't know, but I'm not willing to risk having weak plants again."
Organic substrate
The root problems in bell peppers have affected the entire sector over the past few years. The mysterious plant losses during the first months of the season affected all varieties, not just naturally weaker plants, which has led to a rapid increase in the use of organic substrates in horticulture. Wim Roosen from Dutch Plantin notes that this shift is also reaching other types of cultivation. "We've seen a huge increase in demand due to the root problems in bell peppers, but it's not just bell pepper growers who are switching to organic substrates. Tomato growers are also making the switch, and soon a cucumber grower in Brabant will switch to coco substrate after a successful trial."
Wim encourages growers to make decisions soon because demand is high, and costs will be higher for those who decide later. "By the end of June, we will have allocated most of our production capacity for deliveries until the end of November. Those who decide later might miss out." The mats are shipped by sea from India, which takes two months. "We build in some reserves, and orders placed now will be delivered in October and November directly from our factory in India. Those who decide later will be supplied from stored materials that were produced earlier."
© Dutch Plantin BV
© Dutch Plantin BV
Left: vine tomatoes, right: sweet peppers
© Dutch Plantin BVCucumber growers are also increasingly choosing organic substrate
Beautiful crop
Arie plans to continue using coconut substrate next year, likely with new mats again. "We don't want to take any more risks." The root problems are a major factor in this decision, but so are the consequences: lower production and higher labor costs. Additionally, the atmosphere at the company is completely different now. "Everyone got paid, but no one wants to deal with a crop that doesn't look good despite all the efforts. Now, you see a healthy crop, fruits of great quality, and everything is growing well. There are no drooping plants, and when you look at the roots, you can see that everything is in good condition."
For more information:Dutch Plantin