Simulating sunlight - T5 lights

I have 2 greenhouses I am looking to outfit with T5 florescent lights for stimulating daylight.
1 GH is 4,050 sq and 1 GH is 2,700 sq - canopy areas.
Any recommendations on how many T5 6500k lights i should use for this. I was thinking 4 or 6 lamp fixtures for both houses. I am open to all suggestions, or if I should go with a different style light.
Thanks in advance!


How big of a concern is efficiency? LED’s are really great for growing and far better bang for your buck long term.

1 Like

LED would be fine with me, looking for best way to calculate what is needed. happy with fl or led

1 Like

T5 fixtures are not a good idea in a mixed light greenhouse. The 6 lamp fixtures will cast a huge shadow, which will go against any of the help that the sun and growing in a greenhouse would provide.

Greenhouse top lighting is usually high-output, low-footprint. 1000w HPS fixtures are much smaller than T5 fixtures and put out a lot more light. There are LED options that are very small and put out light equivalent to an HPS.


I’d look into HLG quantum boards. Top grade efficiency and construction, small footprint. You will pay top dollar, and get top dollar results. Granted for a greenhouse that will be a ton of money. Is this for Veg or flowering? Both? You’ll need to factor in cost of electricity throughout the year too - December’s a bitch kinda thing.

1 Like

You should be asking yourself what light frequencies they put out not how many lights I need! if your lights don’t put out 280nm-400nm then your plants won’t produce THC. see for more info.

1 Like

I work with a company called The Sun on Demand, they make a plasma grow light that is 50% more efficient than LEDs.

More importantly, they mimic the exact spectrum of the sun including UVA/UVB + far red that areas that are known to stimulate plant growth. Google the emerson effect, which is outside the range of LED’s and T5’s… These help your plants be healthier, better yields, and more terpenes. Check us out and hit me up if you’d like to know more:

Yes, terpenes are like the plants sunscreen so UV is important. Plasma lights solve this as well =)