Why are leaves changing this color?

Ganggreen99

Active Member
I've been feeding Fox farm trio at 2/3 strength...I haven't had any issues until now. I feed once a week with calmag followed by a regular watering. I have no idea why this is happening
 

xtsho

Well-Known Member
I just always use calmag with every watering.... Should I not?
If you don't need it then you shouldn't use it. Too much calcium can cause issues with the uptake of other nutrients.

They're talking about different sources of calcium than calmag but effect of excessive amounts of calcium can have the same effect in container plants in soil.

"Prophylactic applications of calcium applied as lime or gypsum that are not based on soil test results could create deficiencies in other positively charged nutrients (cations), primarily magnesium and potassium."

 

speedwell68

Well-Known Member
I just always use calmag with every watering.... Should I not?
Where I live, my water contains no Calcium or Magnesium. This has been confirmed by my own test and the water company. I have to add some. Mine get my own homemade CalMag, when I pot them up, at the start of flowering and then every other week during flowering until they begin to ripen. I don't give them much, it is basically a tablespoon of Calcium Chloride and a teaspoon of Epsom Salts in 5L of my normal feed.
 

OldMedUser

Well-Known Member
Deficiencies my aunt Fannie. That's nute burn going on there.

A potassium deficiency would be showing on the oldest lower leaves first but some people think everything is low K. Those leaves look great so it's not low K.

Pour enough pH balanced water through each pot to get the volume of the pot as runoff to reduce the buildup of nutes in there. They don't need high levels of nutes this far into flower so give them a few days before watering again or until they dry down a bit then go easy on some bloom feed and use epsom salts instead of calmag. They want more Mg, S and a bit of K. Should be plenty of Ca left and they don't need lots of that any more either. Nor do they need any N and they can scavenge all the N they need from those dark lower leaves. Can steal P and K from them too.

I've seen this kind of damage a lot and it's generally because the upper leaves are too warm so the plant is sending more water their way. Often the jagged edges of the leaves will bend up making the leaves look all 'saw-toothed' which helps increase evaporation. When nute levels are fairly high nutes get left behind until it becomes toxic and fries the edges. Just short of toxic salts buildup where the whole surface of the leaves will fry like that. That could happen yet.

This stuff takes time so I'd feed about 1/3 less next time for the whole grow.

Good luck!

:peace:
 
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