Best Spectrum – LED grow lights for medical plants

Best Spectrum – LED grow lights for medical plants

Best Spectrum - LED grow lights for medical plantsLED grow lights for medical plants have made considerable advances in recent years. They are now competitive and at times outperform older HID technology – that is if the light has the most favorable spectrum and correct number of bands for plant photosynthesis. So what is the best spectrum for indoor growing with LED grow lights and how many bands of light will give the highest yield?

There are many variations of LED indoor grow lights. Some are made with 2 bands of light, some with 6, 12 15 and more. What does this mean and which one is best? The benefit of growing with LED grow lights is being able to use diodes to target specific wavelengths of light needed for photosynthesis and eliminating extra wavelengths to get the most efficient growing system.

HID lights, on the other hand, give off white light which encompasses all the color of the light spectrum. Hence HID lighting gives of excess heat and wastes energy by using a higher wattage. The best configuration for medical photosynthesis is a grow light with 6-8 bands of light.


Best Spectrum – LED grow lights for medical plants

PAR peaks and highest yields

PAR peaks can be seen on a photosynthetic action radiation chart. Primary peaks are at 630nm (red) and 480nm (blue) and a secondary peak is at 580nm (orange). To cover these peak colors the area around them it is necessary to have at least 6 wavelengths. Adding a couple more wavelengths to balance the spectrum will give the perfect wavelength ratio for indoor growing light.

Any more bands will be excessive and result in a less efficient grow light with a lower yield per watt. If more wavelengths were better, why not grow with a 15-band, 20-band or a 30 band light or more? What about an all-band light which has white diodes and encompassed all the colors of the visible spectrum? Excessive bands of light are counterproductive when it comes to indoor growing.

Having excessive band of light in the grow light defeats the intended purpose of growing with diodes to target only the wavelengths needed. Therefore it is best to include only what is needed and nothing extra. The highest yielding lights will have between 6 to 8 bands of light in the correct weighted average ratios per band.

Best Formulation of Wavelengths of Light

Best Spectrum - LED grow lights for medical plantsTo get the highest yields possible with LED grow lights it is important to have the 6 to 8 bands of light in the correct amounts. The photosynthetic action radiation chart provides a map for the ideal indoor grow light. Taking a weighted average of each diode from the photosynthetic action radiation chart will give the perfect spectrum needed for indoor growing applications.

Research has shown that approximately 60% of the light should be centered around the red wavelengths which make up the primary peak necessary for photosynthesis. The secondary peak around the blue/violet wavelength should make up around 20% of the light.

The final 10% should be allocated to tertiary peak colors and some extra diodes to round our ant balance the entire spectra. Grow lights that are configured with this method will not only provide your plants with the ideal balance of light needed for robust growth but will have the highest yield per watt and highest yield per wattage of electrical consumption.

Led Lighting



  1. ok so heres My question…. If Ive a total of 8 1000 hps lights in a room 20X20… how many NEW LEDs would I Need to replace… OR In other words… what is the multiplier factor??? I j=know how far each 1k hid light covers… no need to buy to many…Assuming using a correct color band fixture???

    1. I too would like the answer to your question (leds neaded to replicate/replace 8 1,000 watt hids)
      I saw a documentary on this exact subject in which they used leds to grow lettuce on a very large scale, along with the different combinations of reds, blues, and even infrared- per different stages of growth- we all know that the vegetation stage is more blue spectrum dependant and the flowering stage is more red dependant, which I also would like to know from those using leds if they have an answer that incorporates the different phases of growth vs the different led combinations, or if they have finally found a “one combination of spectrums that fits all”. That along with the price difference I believe is the most important aspect in the long run and short run both color and energy wise.

  2. I got a pair of G8LED 900W grow lights for $1049 each and they have been serving me well for several grows now. Truly excepctional technology

  3. How expensive are these things? Since I’m retired, and living on a fixed income, cost is extremely important! Also, are they adjustable?

    Doc Jones

    1. high end, 1250 a pop, amazing heat reduction, no need for lamp exhaust fans, yields almost identical to hps. 0 issues thus far.

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