Here are my views on growing with LED and HPS
The strain is Incredible Bulk by Dr. Kripplings and in both grows I've used cuttings from the same plant.
The comparison is between Mars 2 900w and 600w HPS(sunmaster dual spectrum bulb + lumatek dimmable ballast + 100cm parabolic reflector)
(I must say that towards the end of the grow under LED I have added 250w hps for additional light and then a week after the LED died so the plants been finished under 400w hps)
LED True Watts: 450w+-5% used from the start
HPS: 3 different sunmaster bulbs used: 250 w, 400w and 600w in flower. (to reduce energy costs)
Feeding schedules: On the both grows been the same with the only difference that I haven't used Green Planet Massive on the HPS run.
Veg time on both grows: 6 weeks
Training methods used: LST and supercropping.
Just a comparison photo - These photos are both taken at Week 7 Day 3 after flip - The one on the left is grown under Mars 2 900w + additional 250w HPS and the one on the right under HPS 600 and parabolic shade.
I truly enjoyed growing this strain under both different lights. Considering I used 3 different bulbs during the HPS run I think the average electricity consummation is pretty much the same BUT. There is that big BUT. As I am growing in the attic the temperatures in the attic can drop a lot. Even with the lights on in the winter I had temperatures under 19-20 degrees. So I had a fan heater wired to my controller to kick in every time the temperatures dropped under 22. You can imagine that the fan heater was pretty much constantly on and that increased my electricity consummation big time.
Light spread - as the MARS 2 900 was advertised to cover my grow area which is 1.2 x 1.2 I don't think it really did. Maybe it needed just a bit more and it would fit perfectly in that size tent but there was some lack of light in the corners of the tent while the parabolic shade and the hps covered it perfectly.
Light penetration and bud density: I've used the same lollypoping technique 2 weeks after the flip on the both runs. I am against removing any fan leaves from the top of the canopy so I have only removed the lower 1/3 of the plant. I must say that the penetration of the HPS was much better than the one of the MARS. With the LED I had lots of fluffy lower growth(undeveloped buds) while with the HPS it was nice buds everywhere! And I mean everywhere!
There was difference in the colas structure as well. HPS produced mostly 6 inch colas while the LED produced short bulky colas.
Bud Density under LED I will rate 10 of 10. I truly is amazing. Rock hard nugs.. but on top of the canopy only. HPS imo is 9 of 10 but everywhere. Some people the crystals production under LED is much better than HPS.. I think this time with me was the other way round.
Something else I also noticed is that the stems of the plants were much stronger under HPS. I've used the same amounts of Liquid Silicone during both runs.
Yield: Both runs been chopped on week 8 at 100% cloudy trichomes. That's how I like my smoke. Unluckily I found some rot during the HPS grow and I had to bin between 14-28 grams of bud. The results were: LED - 581 grams HPS - 625. On average I will rate the bud quality under LED 6 of 10 and the hps 8 of 10(Allowing 2 points for my next grows so it can be perfect lol )
Photos just before chopping: LED on the left and HPS on the right
In general I think the LEDs have bright future ahead and maybe there are units on the market which are much better than the one I was using. The only thing is that they are very expensive. In a perfectly controlled environment I think they will perform great in future!
And should I say something about the HPS? Well I think you all know the answer - The oldschool methods still rock!
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