More experimenting with lighting has led us to a new low cost configuration for LED's that are well suited for growing microgreens. We have found through our experimentation that microgreens are fairly happy with lower light levels as they grow out in such short time spans. We have found that light levels as measured by wattage is not as critical as we first suspected. Light wavelengths have proven to be of higher value for initial growing experiments.
Microgreens after several days of darkness will unfurl cotyledon leaves when then start the photosynthetic reactions for greening. We have found over a pretty large range of CFL grow lights and LED's of red/blue and blue spectrums that variance was not significant and we could obtain good results even with really lower light levels. This was surprising to us as an outcome since most research and marketing pointed out that higher levels of lighting would normally reward the user up a point. This prompted going down in power to experiment.
We have now put up an inexpensive array of low power LED's to test the hypothesis. See the picture of the installation on the bottom tray of a modified rack system. Using now 5 5W strips for the light array. This experiment was prompted by our use of the low power commercial bright white LED sign lighting in our LED Grow Lights. Extremely low power and full spectrum. So reasoning was spectral selective low power LEDs will provide enough grow lighting, virtually no heat and more than enough PAR radiation to grow out microgreens.
The new array will be used to grow out a larger surface under our bottom tray and so far it compares favorably to our top units which are 28W corncob lights with reflectors. The bottom light is less than 1/2 of the upper trays. Experiments are ongoing now and we are planning another round of lighting experiments by varying our times and colors ... stay tuned!
Urbaform is a technology integrator and developer specializing in food production in the urban environment ...