Why so little light? Cannabis thrives under high light conditions, including significantly increased plant yield and plant quality.
The plant on the right has the appearance of a plant that has not been given enough light - it's tall with significant internal space and limited foliage. Seeing that it was grown under a veg light, I'd posit that the light level has been low for some time. My rationale for that is that veg lights, with their blue-heavy spectrum, are used to control canopy height and to grow short, compact plants. That's not what I'm seeing in this photo.
I've attached a photo from my current grow. The plant was vegged with a Growcraft X2 veg light and light levels have bee in the 70mol range. The plant is a Chemdog (photo) and is about 70 days old in these pictures. The inflorescence is very dense and the internodal space was so low that it was damned near impossible to work in.
When I flipped a week ago, she was 38" x 24"x 12" tall (the tent is only 24" deep so the front "row" of the plant is pushing up against the tent flaps). As a result of the short internodal space in the plant, the canopy will tend to be even and the plant will tend to yield large colas.
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This picture is from an auto flower grow last year. Same veg light + flower light combination as current grow.
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That growing style might not be everyone's cup of tea I've found yield to be significant. In that grow, the plants yielded 21 ounces in one and five ounces in the other, for a total of 26 ounces or almost 1kg per square meter.
Below is a graph derived from the a research paper. The increase in yield is not linear, no question, but it does also indicate how responsive cannabis is - by increasing DLI from an average of, say, 600 to 800 - a value that is easily achievable by many LED grow lights - yield increased by just under 20%. Not bad for spending $35 on a light meter and turning up the dial a bit.
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