Project Het Seminar

At the beginning of December 2021, we realized the first part of this project in the basement of restaurant “Het Seminar” in Zenderen, Netherlands. The Seminar, in possession of a green Michelin star, aims to become 100% self-sufficient. In addition to meadows, vegetable gardens and a food forest, there is now also an indoor garden.
The first part consists of 10m2 of cultivation surface, spread over 2 floors, for growing leafy greens and herbs.
The set-up consists of a pallet rack in which 10 grow trays of 140 x 70 x 15 cm are placed. These are continuously filled from a water tank (wheelie bin) with a water/nutrient solution until there is a level of about 5 cm. With this so-called hydro cultivation method, the plants hang directly with their roots in the water. So no messing with soil or other growing medium.

For the lighting, we opted for 18 pieces of 80 Watt LED grow bars. The entire installation consumes 1440 Watts for the lighting. In addition, about 300 Watts of electricity are consumed by pumps and ventilation systems.

In February 2022 we were asked to build a second part. This time for growing tomatoes and peppers. The hydro cultivation apparently went well because this modus also had to be applied here.
This time we used square PVC pipes that are 150cm long. 7 Pieces in total. To create the same “look” as the first set-up, we again used a pallet rack to place the tubes. Here too, the plants are in baskets that are connected to two water tanks (wheelie bins) for the water supply and drainage.

Because tomato and pepper plants can grow quite large, only one floor can be realized. Growing flowering, fruit-bearing plants requires considerably more light than growing leafy vegetables and herbs. That is why the lighting also had to be adjusted. In this tomato grow rack of approximately 3.4 m2 surface 4 LED grow lights with a power of 250 Watt each are used. So per m2 there is 294 Watt of lighting above the tomatoes. For comparison, there is 144 Watt per m2 above the first cultivation set-up for leafy greens.

The lamps used in the tomato arrangement are dimmable. As a result, less light can be applied in the initial phase when the plants are still small and have less light need. This also saves energy.

There are approximately two months between the delivery of the first and second part of the nursery. When we were installing the second part, the first part was already in full bloom and the cooks were coming and going to harvest the crops.