A full spectrum of light.
Visible Light
Visible light (400 to 700 nm) accounts for 43% of the energy in the global solar irradiance spectrum (300 to 2500 nm). The balance arrives as 52% near-infrared (NIR; 700 to 2500 nm) and 5% ultraviolet (UV; 300 to 400 nm)1Levinson, R., Berdahl, P., & Akbari, H. (2005b). Solar spectral optical properties of pigments– part II: survey of common colorants. Solar Energy Materials and Solar Cells, 89(4), 351- 389..
Pigments
Ultra-violet light can cause significant visual and photosynthetic damage to turfgrass species in only a short period of time4Ervin, E. H., Zhang, X., & Fike, J. H. (2004). Ultraviolet-B radiation damage on Kentucky bluegrass. I. Antioxidant and colorant effects. HortScience, 39(6), 1465-1470.. As a result of this it has been found that to reduce this you can apply synthetic green pigment to Poa pratensis and get significantly higher visual quality and photochemical efficiency.
What is a full spectrum grow light?
A full spectrum grow light provides the optimal light needed for turfgrass to fully photosynthesise and recover from wear in shade areas. By using full spectrum grow lights you are able to grow turfgrass from seedlings to full maturity.
Blue light
Red light
Questions
If I have an infrared heater won’t it throw the light spectrum out?
This is an interesting question. In order to answer it you have to realise that infrared light is further to the right of the visible light spectrum that turfgrass generally uses but that Infrared waves can also affect how plants grow.
An “infrared heater” converts electricity into light and heat as well as emits infrared light.
Turfgrass cannot make use of infrared light for photosynthesis because they lack a pigment which can utilise light with that wavelength.
Plants grown in light that is too red may seem spindly and long-stemmed. Too much infrared light, especially in the far red end of the spectrum, may actually damage plants.
Can red light help fight disease?
There is evidence suggesting that exposing plants to red light increases levels of salicylic acid (SA) and induces SA signalling which is vital for plants to survive fungal infections. That’s all well and good but doesn’t mean you should bombard your turfgrass with red light unless you want it to etiolate. In response to too much red light, it will just make your turf stretch and bleach.
As we keep mentioning a wide LED light spectrum is best which includes red and blue (plus others). If you’re concerned about increasing salicylic acid levels you can make exogenous applications using Vertmax Duo turf pigment which already contains this within its proprietary formulation. That way you increase SA levels get an instant green colouring and avoid your turf becoming like straw!
Does turfgrass mainly use red light?
Contrary to what some say turfgrass uses both red and blue light. Turfgrass gets the hots mainly for blue and red wavelengths. LED grow lighting that only has those colours will not seem very bright but it will be quite effective for grass growth.
References
Graduated from Newcastle University with an Hons Degree in Soil Science in 1988, Jerry then worked for the Sports Turf Research Institute (STRI) as a turf agronomist before emigrating to Australia in 1993.
He followed this by gaining a Grad Dip in Business Management from UTS. He has worked in a number of management roles for companies as diverse as Samsung Australia, Arthur Yates and Paton Fertilizers.
He has always had a strong affinity with the Australian sports turf industry and as a result he established Gilba Solutions as an independent sports turf consultancy in 1993. Jerry has written over 100 articles and two books on a wide range of topics such as Turf Pesticides and Nutrition which have been published in Australia and overseas.