With the use of vertical towers, it's now possible to cultivate the same amount of lettuce on just 20m² as a grower would on 200m². Dutch Lion has developed a growing system for this purpose, which is currently being tested at the World Horti Center in Naaldwijk. At the same time, an anthurium grower is evaluating the system for propagation, and larger projects are already in development.
Founder and Managing Director, Vincent van der Gaag, provides an update at the end of February. He presents this update the day before an official harvest celebration with invited guests, while offering a bird's-eye view of the striking cultivation system.
In Naaldwijk, the cultivation system was installed last autumn, and butterhead lettuce cultivation began in January. The goal is to continue growing a variety of crops at the World Horti Center to validate the system and showcase its potential to the market.
The test greenhouse features a setup with four monorails, each supporting 30 cultivation towers. Currently, each tower holds 42 heads of lettuce, but this capacity can be expanded to 60, significantly reducing the amount of space needed for production. "It saves 90% of the space," Vincent calculates.
The plants in the cultivation towers are watered via drippers
A hybrid approach
Dutch Lion has intentionally avoided labeling its system as "vertical farming." According to Vincent, the vertical farming industry has faced significant challenges, particularly during the energy crisis, when many companies struggled with the high costs and complexities of fully automated, multilayer growing systems without natural light.
"Many investments failed, companies had to shut down, and some went bankrupt because the unit economics simply didn't work," he explains. "Greenhouses, on the other hand, utilize free daylight and rely on proven technologies that have been successful for decades."
The trial is equipped with daylight LED. Dutch Lion is brand-independent for LED lighting.
Dutch Lion focuses on integrating the strengths of both vertical farming and greenhouse growing. The system was initially developed and extensively tested in a container-based, daylight-free setup. Now, it's being deployed in a greenhouse environment, marking the next stage of its evolution.
For the trial, the cultivation towers were numbered with notes.
Smart mechanical design
The greenhouse system still incorporates elements of the smart, mechanical carousel technology previously used in cultivation containers. However, the tall cultivation towers no longer rotate. Instead, they move forward throughout the growing cycle, from seeding to harvest.
This system operates similarly to a mobile gutter system for hydroponic growing, where gutters shift apart to provide more space. However, in this case, the movement happens vertically. The towers automatically spread apart as the lettuce grows, ensuring optimal spacing.
"We start with an 8cm spacing between plants, and by the end of the cycle, it's 22cm," Vincent explains. A single cylinder at the front controls the entire monorail system mechanically. "This design reduces maintenance and keeps the system as simple as possible."
The towers consist of plastic parts that can be linked, and also made horizontal.
Managing light and airflow
One challenge with vertical growing in a greenhouse is ensuring adequate light reaches the lower plants. To address this, the trial setup includes PAR sensors that measure light levels, allowing the daylight LED lighting to adjust accordingly. "Vertical farming requires more light than horizontal cultivation, but we offset this with lower labor and heating costs since we're operating in a much smaller cultivation area."
To maintain a consistent climate throughout the towers, vertical airflow is used. Air hoses ensure even air distribution, balancing temperatures between the top and bottom sections of the system. "We control the airflow ourselves, while the climate chamber regulates the overall conditions," he adds.
Air hoses with holes ensure airflow
Optimizing unit economics
Dutch Lion's approach has already attracted interest from investors experienced in the vertical farming industry. "Our system is designed with unit economics in mind," Vincent says. "This was a major challenge in previous vertical farming projects."
By shrinking the required greenhouse footprint by 90%, Dutch Lion reduces the project's capital expenditure (CAPEX) by 40% compared to a fully automated greenhouse. This results in a 20% lower crop cost than conventional horizontal cultivation systems.
Dutch Lion firmly believes in the future of hybrid growing, and other companies in the horticultural sector are also exploring unconventional cultivation methods. Many of these new systems aim to reduce labor costs and introduce advanced automation.
At the World Horti Center, Biomic Agritech is running a similar system, while Saia Agribotics is testing a method in Ede that moves tomato plants to processing areas instead of requiring workers to move through the greenhouse. These innovations challenge the market to rethink labor and efficiency.
Below, water drips from the cultivation towers. With this way of growing, water usage is kept low. "We found that we have up to 70% less watering compared to horizontal mobile guttering systems - which saves significantly on CAPEX and water consumption," Vincent (left, beside the screen) shared with a group of invited guests on 6 March.
Indoor Ag-Con
Although the current setup focuses solely on the production phase, the entire cycle, from automated sowing and transport to harvesting and tower cleaning, can be fully automated. "The cycle is sacred," Vincent emphasizes. "Harvesting and re-sowing every day is important. That way, the crops grow optimally, 365 days a year." Short crops are preferred. "The longer the crop, the higher the cost of supplemental lighting."
Dutch Lion primarily targets new-build projects with the system, but it is also possible to install the system in existing greenhouses. The weight of the system is comparable to that of hanging gutters for tomato cultivation, for example, Vincent notes.
On March 11 and 12, Dutch Lion will be present at Indoor Ag-Con, where visitors can find them at stand 725.
For more information:
Vincent van der Gaag
Dutch Lion
[email protected]
www.dutchlionag.tech