Someone should be able to recognize this, and it happens on a repetitive base, with different strains.
Right around week 4-5, there is a sudden darkening of the canopy that happens literally overnight. One day they are all light green and lime and the next they get dark and remain that way until then end. Results are fine, but I think this is not normal and there should be a way to keep them light green until the end.
Nitrogen is the main focus of my experiments, I have reduced it a lot, especially after I flip them, I have attempted to reduce it further even getting yellowing in lower leaves, however I can never seem to save them from darkening eventually. Sometimes beginning of week 6.
My main question is, could this effect be anything else than excess nitrogen? Does something else cause this darkening?
Also, is this perhaps normal? I know it is not strain related as I have tried various.
I do see some clawing and the smaller plants and those with weaker genetics definitely show nitrogen excess symptoms, at least that's my read.
This has been happening my 5-6 grows as this is a repetitive production cycle. All other factors the same, reducing Nitrogen has not shown great improvement. The following pair images are taken 1 to 2 days apart and see the difference.
Plants are visibly happy at all times, but something is off.
I will provide some more information that will hopefully help you identify the problem.
This is a SOG, no training grow, 4 weeks growing and 9 weeks flowering. I use organic base nutrients from Plagron.
Soil is Plagron Lightmix. Peat based with a little starting mineral food.
Alga Grow NPK (4-2-4) in growing stage (3-4 weeks).
Plagron Alga Bloom NPK (3-2-5) + Green sensation NPK (0-9-10) + a little P/K booster (0-13-14) (mineral)
Also in flowering I brew compost teas with almost every watering. There is some extra nitrogen in the tea which amounts to additional 30-50ppm but I have tried to cut on the tea until week 5 and it didn't help with the darkening problem.
Calmag is from General Hydroponics, I believe it was 1 or 0 nitrogen in the NPK. Intentionally I found the one with least nitrogen.
I also added PK with the idea to further reduce the base nutrient that seems to have a lot of nitrogen.
Overall I feed a lot under what is suggested by Plagron calculator.
* some theories I work on include:
- high temps of 30-31 degrees (84-87F) might cause excessive evaporation and water uptake, that might forcibly make the plants to update excessive amounts of Nitrogen. I've read that this temperature range is fine and recommended for LED, and I keep VPD in range. What do you think?
Although temps in weeks 1-5 are more around 28-29 degrees. (82-84 F)
- I notice that my C02 tends to accumulate at night above 2000ppm. Could this be a problem?
- Low light intensity (Plants are unable to use all nitrogen)
Here is also my environment parameters.
Some more images from around week 5-6. Strain is Cookies Gelato from Royal Queen seeds. This particular grow turned out fine, but I've had much worst in the past.
Right around week 4-5, there is a sudden darkening of the canopy that happens literally overnight. One day they are all light green and lime and the next they get dark and remain that way until then end. Results are fine, but I think this is not normal and there should be a way to keep them light green until the end.
Nitrogen is the main focus of my experiments, I have reduced it a lot, especially after I flip them, I have attempted to reduce it further even getting yellowing in lower leaves, however I can never seem to save them from darkening eventually. Sometimes beginning of week 6.
My main question is, could this effect be anything else than excess nitrogen? Does something else cause this darkening?
Also, is this perhaps normal? I know it is not strain related as I have tried various.
I do see some clawing and the smaller plants and those with weaker genetics definitely show nitrogen excess symptoms, at least that's my read.
This has been happening my 5-6 grows as this is a repetitive production cycle. All other factors the same, reducing Nitrogen has not shown great improvement. The following pair images are taken 1 to 2 days apart and see the difference.
Plants are visibly happy at all times, but something is off.
I will provide some more information that will hopefully help you identify the problem.
This is a SOG, no training grow, 4 weeks growing and 9 weeks flowering. I use organic base nutrients from Plagron.
Soil is Plagron Lightmix. Peat based with a little starting mineral food.
Alga Grow NPK (4-2-4) in growing stage (3-4 weeks).
Plagron Alga Bloom NPK (3-2-5) + Green sensation NPK (0-9-10) + a little P/K booster (0-13-14) (mineral)
Also in flowering I brew compost teas with almost every watering. There is some extra nitrogen in the tea which amounts to additional 30-50ppm but I have tried to cut on the tea until week 5 and it didn't help with the darkening problem.
Calmag is from General Hydroponics, I believe it was 1 or 0 nitrogen in the NPK. Intentionally I found the one with least nitrogen.
I also added PK with the idea to further reduce the base nutrient that seems to have a lot of nitrogen.
Overall I feed a lot under what is suggested by Plagron calculator.
* some theories I work on include:
- high temps of 30-31 degrees (84-87F) might cause excessive evaporation and water uptake, that might forcibly make the plants to update excessive amounts of Nitrogen. I've read that this temperature range is fine and recommended for LED, and I keep VPD in range. What do you think?
Although temps in weeks 1-5 are more around 28-29 degrees. (82-84 F)
- I notice that my C02 tends to accumulate at night above 2000ppm. Could this be a problem?
- Low light intensity (Plants are unable to use all nitrogen)
Here is also my environment parameters.
Some more images from around week 5-6. Strain is Cookies Gelato from Royal Queen seeds. This particular grow turned out fine, but I've had much worst in the past.