# Brown spots on leaves week five in flower



## Jkjiv (Dec 9, 2020)

Week five of flower showing brown spots on leaves, my best guess from reading up on it is calcium deficiency.  All water for them comes from a dehumidifier nearby in the basement.  We are feeding once a week with big bloom and tiger bloom and also twice since beginning of flower with sledgehammer 3 weeks apart.  I read that calcium deficiency can stunt bud growth.  No sign of any kind of pests on underside of leaves either.
What can I do to get on top of this?


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## WeedHopper (Dec 10, 2020)

Slight magnesium deficiency i would say.


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## bigsur51 (Dec 10, 2020)

give them girls a shot of cal-mag 2-3 times a week


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## Jkjiv (Dec 12, 2020)

WeedHopper said:


> Slight magnesium deficiency i would say.


Went looking g for cal-mag, no luck. Did find this though...


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## Jakefish (Dec 13, 2020)

Careful with that stuff.  Super concentrated and really easy to nute burn everything.  I use the open sesame version of that stuff


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## zem (Dec 13, 2020)

Around that time in flowering, brown spots could also be due to salt buildup. Also calcium appears on new leaves first


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## Jkjiv (Dec 14, 2020)

zem said:


> Around that time in flowering, brown spots could also be due to salt buildup. Also calcium appears on new leaves first


We hit them with sledge hammer as soon as we read up on this should we do it again? Earlier than 3weeks?  Brown spots seem to be mainly on older leaves btw.


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## Jkjiv (Dec 14, 2020)

Jakefish said:


> Careful with that stuff.  Super concentrated and really easy to nute burn everything.  I use the open sesame version of that stuff


Ok, thanks for the warning


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## zem (Dec 15, 2020)

Jkjiv said:


> We hit them with sledge hammer as soon as we read up on this should we do it again? Earlier than 3weeks?  Brown spots seem to be mainly on older leaves btw.



I just use ph'd water to wash the medium then i feed normally but i am growing in a hydro system and i have no worries about overwatering. If you are in soil, i guess you could use RO water with a light feeding. The most important mineral that you want to purge from the medium is sodium that accumulates quickly to levels that cause damage. Sodium is present in all mineral water and in most ferts. If you are not washing your medium like what rain does in nature, sodium will acuumulate. There is no way to precipitate sodium in the medium as fas as i know so any product will not be targeting sodium will not solve this issue.


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## WeedHopper (Dec 15, 2020)

Funny how sodium can mess up your plant and you. To much is bad for both of you.


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## bigsur51 (Dec 15, 2020)

just be glad it’s not brown spots on your shorts


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## BeeKeeper2 (Dec 16, 2020)

Jkjiv said:


> Week five of flower showing brown spots on leaves, my best guess from reading up on it is calcium deficiency.  All water for them comes from a dehumidifier nearby in the basement.  We are feeding once a week with big bloom and tiger bloom and also twice since beginning of flower with sledgehammer 3 weeks apart.  I read that calcium deficiency can stunt bud growth.  No sign of any kind of pests on underside of leaves either.
> What can I do to get on top of this?


  JK .. I was using the water from dehumidifier and it started getting slimy in the catch container. Is this bad for plants? I stopped using it, because after cleaning it with bleach water it just came back week or so.


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## bigsur51 (Dec 16, 2020)

BeeKeeper2 said:


> JK .. I was using the water from dehumidifier and it started getting slimy in the catch container. Is this bad for plants? I stopped using it, because after cleaning it with bleach water it just came back week or so.




i have heard that dehumidifier water is bad for cannabis plants


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