Grow Lights Australia
Well-Known Member
With all the debate over which light is better, we thought it would be interesting to document a hybrid CMH/LED grow, as we believe the two light sources can be complimentary – even if CMH isn't as efficient as LED 
We were contacted by a grower who wanted to get into LEDs but had already invested in CMH. Originally he had two 315W single end High Par lamps and a 600W HPS in his 4.5' x 4.5' tent and wanted to replace everything with LED. It was a lot of light and a lot of heat – especially in summer. We suggested keeping the CMH lamps and replacing the 600 HPS with a couple of High Red boards running at 240W. He took our advice and put the CMH lamps in each corner and the High Red boards diagonally down the middle for a nice even 1000PPFD across the canopy.
The 3000K CMH lamps already had a nice UVA and near-UV output, so we figured the 2800K High Red boards would add a red spectrum boost while reducing the amount of heat in the tent. Here's what the blended spectrum looks like with the above ratio of 3:1 CMH:LED
I'm hoping to update this grow every week as the guy who owns it is very happy with the results so far. Published here with his permission, here's his grow at two weeks of 12/12.
The strain is an unknown clone, believed to be an Afghan-Skunk cross that yields very well. This is a single plant grow in another hybrid system: run-to-waste perlite and coco. Here's a picture of the drainage pipe exiting the 30-litre pot. These photos don't really do the plant size justice. He's hoping to get 2.5-3lb from this 7-8 week grow.
We were contacted by a grower who wanted to get into LEDs but had already invested in CMH. Originally he had two 315W single end High Par lamps and a 600W HPS in his 4.5' x 4.5' tent and wanted to replace everything with LED. It was a lot of light and a lot of heat – especially in summer. We suggested keeping the CMH lamps and replacing the 600 HPS with a couple of High Red boards running at 240W. He took our advice and put the CMH lamps in each corner and the High Red boards diagonally down the middle for a nice even 1000PPFD across the canopy.
The 3000K CMH lamps already had a nice UVA and near-UV output, so we figured the 2800K High Red boards would add a red spectrum boost while reducing the amount of heat in the tent. Here's what the blended spectrum looks like with the above ratio of 3:1 CMH:LED
I'm hoping to update this grow every week as the guy who owns it is very happy with the results so far. Published here with his permission, here's his grow at two weeks of 12/12.
The strain is an unknown clone, believed to be an Afghan-Skunk cross that yields very well. This is a single plant grow in another hybrid system: run-to-waste perlite and coco. Here's a picture of the drainage pipe exiting the 30-litre pot. These photos don't really do the plant size justice. He's hoping to get 2.5-3lb from this 7-8 week grow.
