This particular plant is in
its fifth week of flowering
I’m having similar issues with my two indoor plants. One is Northern lights and the other is Bubble Gum. I’m pretty sure it’s because I messed up the PH of the water when feeding my plants during the transition from veg to flower and caused a nutrient lockout. At this time I also noticed stems turning a dark purple which i read could be stress. As shown in the pictures the Nl has significantly more purpling in the stems. I’ve tried my best to correct the problem but now I’m about 2 weeks away from harvesting and going to start flushing. The leaves are showing more signs of deficiency now but I also know that some of is caused naturally when the plant is in bloom and sucking up all the nutrients. Do you think the damage that’s been done already will affect the harvest in any detrimental way? Thanks, any advice is appreciated!!!
I also have exact issues and marking with my AK plant outdoor pot grown. PH is a solid consistent 6.5. Also soil test done for phosphorus, nitrogen, and potassium. Levels also solid. Haven’t tested micro nutrients. Flowers are 4 weeks into flower. I believe it’s a deficiency or sort but not sure any
recommendations.
Hi Smax,
This looks like Manganese deficiency. There could be a couple of factors. First, your Water PH level should be between 6.0 and 7.0 for soil. You must keep it between these numbers to avoid nutrient lockup. Similar symptoms could also mean too much Iron.
For newer growers with similar issues, there are various possibilities for black spots.
One of the main reasons is a pH rate which is too high.
However, as stated by another user, manganese deficiency is the most likely culprit.
In some cases it might also be a calcium excess.
Sheesh, sorry for necro bumping, but I’m having some similar issues popping up in flower - blackened spots on leaves that are fading out probably too quickly.
My area IS known for excessive iron, but I also heard a professor from McGill university on the Cannabis Science podcast saying he sees a shocking amount of iron deficient plants in Canada, so I was thinking maybe it’s not this at all… Perplexed
Thank you, MidwestGuy
Any chance you can show me excess iron?
I believe we have an abundance in our water supply, same water I’m using on the plants unfortunately. I know the water softener salts the big stores sell in town all have more expensive Iron Reducing versions because our toilets can get red rings otherwise
I’ve never seen an iron excess.
1 Like