By Thomas Brown


Your light source is the limiting factor for your potential yield, so consideration must be made on your choice of grow light.  Plants thrive under a full spectrum light source,  however during the vegetative stage plants prefer the blue end of the spectrum.  When plants have access to this “sky blue” light they grow more effectively rather than climb towards the light.


When plants have access to full spectrum light, with the focus on the blue end of the spectrum, many benefits are to be seen.  The plants will be short and stocky and have thicker stems,  with better (shorter) internodal spacing.  You will also see more dark green foliage as blue light is responsible for chlorophyll production.  Stomata production will also increase, these are essential for CO2 intake (used for photosynthesis) and for the plant to release oxygen and water.  To put it simply the stomata are the lungs of the plant.  


We would recommend using a metal halide lamp for the vegetative process,  which we stock the Sunmaster brand in 400w and 600w variations.  We would suggest using a 400w metal halide lamp for a 1.2m area.  This lamp may produce that much needed blue light, however a supplement of other parts of the spectrum (red) are recommended for improved photosynthesis.  


This can be achieved best by using the Maxibright daylight ceramic metal halide lamp from Philips.  These lamps produce an almost perfect full spectrum.  There are two lamps for this method,  The Philips MASTERcolour CDM-TMW Elite 315w and the Philips MASTERcolour CDM-TMW Elite Agro 315w EL.  The first of these lamps are centered on the blue end of the spectrum whereas the Agro is more focused on the red spectrum for the flowering stage.


Using a full spectrum light like the Maxibright Daylight kit you will see improved sugar production from the plant through photosynthesis.  This affects growth, plant health, the root system and how the plant reproduces.  To put it simply the more spectrum you give them the more of the natural plant genetics shine through!


Another important factor in using your light efficiently is not to crowd your plants as this will make if difficult for the plant to breathe through the stomata by increasing relative humidity in the plant foliage. If the humidity is too high (over 60%) the plant is unable to release oxygen and water and to absorb CO2 into the leaf from the stomata.  Any leaves that are shaded by leaves above will lose the much needed spectrum and the guard cells of the stomata will close and not be used for the photosynthesizing process.


In summary there are many factors to a bumper crop,  if you follow the principles of plant biology your yield will increase more rapidly than the next new nutrient on the market could ever achieve.  Your light source and how you use it is the first place to look at if yield is not upto scratch.  We recommend you invest in good full spectrum lights (Maxibright Daylight 315w) and the results will speak for themselves.  If you are unable to afford this on your first set up,  then we would recommend a good quality brand like the Eurloux light kit with dual spectrum lamp or go for a digital dimmable sunmaster light kit.


Any questions on this topic you are welcome to call The Grow Superstore in Peterborough on 01733 331115. Happy growing!