At the beginning of March the new substrate steaming technology was tested at a flower farm located near the German-Dutch border. A special challenge of this task was to avoid shifting of very light pumice-like clay substrate in special trays for planting flowers. Moreover, irrigation hoses installed on the bottoms of the planting trays shall not directly be exposed to temperatures exceeding 110°C.
This solution was developed and put into a trial operation by a service team of Marten Barel Consultancy B.V., a well-known consulting company for hot steam applications.
The flower farm, which has successfully tested the new technology, specializes in high quality crops, especially amaryllis.
After the culture is harvested and all plants are pulled out from the substrate, a special steam hose is laid on the substrate along the longitudinal axis of the plant tray. The steam hose is extremely steam-permeable and, thereby, uniformly gives off the stream along the entire plant tray. The plant tray and the hose laid in the middle of it are covered with a heat-resistant steam foil whose edges are weighted with appropriate weighting hoses.
As soon as the steam boiler is connected and started, the substrate starts to be gently steamed. Since the steam is slowly guided through the clay substrate and condensed in it, the irrigation hoses installed at the bottom of the plant tray are not exposed to excessive heat. The steaming time is very short. In already 30 minutes you can sanitise a plant tray of up to 50m length when only using ~30-40kg steam per cubic metre. As the substrate shall not be moved or shifted, additional labour cost is minimal.