To grow any crop, you need light. It is not just the amount of light that is important, but also the quality. Removable coatings for the greenhouse roof have been developed that change the sunlight’s properties for optimal plant growth.
Diffuse light
The use of diffuse light is a trend, not only in the Netherlands but in the whole of Western Europe. A diffuse coating on the greenhouse cover retains a similar amount of sunlight in the greenhouse, but the distribution of the light over the crops will improve. By applying the diffuse coating, there will be less light at the top and more light at the bottom of the plants. The amount of direct sunlight decreases, which results in less combustion; the plants remain cooler and are less likely to be stressed. Because more sunlight is let in, there will be more energy for photosynthesis. It is now scientifically proven that plants will perform better: it can quickly result in an additional growth of several percent. These types of coating will especially prove useful for chrysanthemum, phalaenopsis, anthurium, and other potted plants which need a lot of light.
Heat shielding
Traditional coatings block out as much light as heat. Some plants require more light, but not so much heat. The manufacturers have developed heat-shielding coatings. The coatings contain a pigment that reflects a larger proportion of the heat radiation (Near Infrared). It will stay cooler in the greenhouse, and the plants will still get sufficient PAR light (Photosynthetically Active Radiation). A small proportion of the PAR light will be reflected, though. These products are widely used in growing chrysanthemum, gerbera, rose, amaryllis, lily, phalaenopsis, and hortensia.
In some coatings, the diffuse and heat-shielding properties are combined, as they are in D-Gree, Optifuse IR, and ReduFuse IR. These coatings diffuse a lot of PAR light but keep a proportion of the NIR radiation outside the greenhouse. These types of coating are widely used in growing chrysanthemum, alstroemeria, and amaryllis.
There are several companies at GreenTech, which sell special coatings for greenhouse covers.
CompanyCountryBooth # at GreenTech
Mardenkro Netherlands 10.200
Sudlac France 10.316
Royal Brinkman Netherlands 11.108
