Plants need photosynthetically active radiation
Growers cannot simply use any lamp because different plants have different lighting needs. They require different wavelengths for optimum growth. Ivy, for example, likes shade, whereas cacti and any plants that grow naturally around the Mediterranean, on mountains, or in savannas need lots of light. Plants need the right level of “photosynthetically active radiation” (PAR) for photosynthesis and plant growth to occur. In other words, the wavelength of the lamp must be optimized for the type of plant being grown.
Greenhouses are small autonomous ecosystems
In a large greenhouse covering ten hectares (about 25 acres) there will be 10,000 lamps each rated at 1,000 W, so one megawatt of electrical power is needed. Some very large greenhouses have their own gas turbines to supply power. Karen Twesten said: “The waste heat is also used to heat the greenhouse in winter, and the carbon dioxide is fed to the plants. The tomato plants, which are illuminated by the 1000 W Plantastar lamps, are pollinated by humble-bees. And there are separate companies that breed bees for this purpose, as well as companies that only produce seeds and grow young plants.” It’s a system that works well and has an established infrastructure.
As with the other products in the series, the success of the new Plantastar 1000W Plus will depend on the yields from the harvests. “The growers are harvest experts, not lighting experts”, said Karen Twesten. “Only if the yield is right will the growers be prepared to invest in the new Plantastar. They therefore rely totally on our know-how as manufacturers.”