Problems with brown dots on leaves turning yellow and dying

I struggle to diagnose what's wrong with my 2 plants. First they were infested by mites. After 2 applications of some spray it looked like things were getting better. But now, I'm facing a different problem. Dark (mostly brown) spots are appearing on leaves, then the leaves are turning yellow and dying. I thought it was lack of magnesium so I bought epson salt but it didn't help. Then I thought it was lack of calcium and so I added some milk (too crazy?) into the water. But I can't see any improvement. The grow medium is mix of soil and coco, I try to keep pH around 6.5.

Any idea please?

Milk will not work, thats the wrong kind of calcium. It does kind of look like calcium deficiency, go to the garden center and get a Cal-Mag product, and use it for a week or two and see if that helps. Make sure your ph is 6.0-6.5, you can dump all the nutes you want on a plant and if your ph is wrong it'll still starve

jimcz said:

I struggle to diagnose what's wrong with my 2 plants. First they were infested by mites. After 2 applications of some spray it looked like things were getting better. But now, I'm facing a different problem. Dark (mostly brown) spots are appearing on leaves, then the leaves are turning yellow and dying. I thought it was lack of magnesium so I bought epson salt but it didn't help. Then I thought it was lack of calcium and so I added some milk (too crazy?) into the water. But I can't see any improvement. The grow medium is mix of soil and coco, I try to keep pH around 6.5.

Any idea please?

Click to expand...

Roger A. Shrubber said:

Milk will not work, thats the wrong kind of calcium. It does kind of look like calcium deficiency, go to the garden center and get a Cal-Mag product, and use it for a week or two and see if that helps. Make sure your ph is 6.0-6.5, you can dump all the nutes you want on a plant and if your ph is wrong it'll still starve

Click to expand...

Oh for Christ sake....

Yeah a Ca/Mg should be being used. 5ml per gallon of solution. It will take around a week to show and the damage will NOT repair. Look for any changes in the "New Growth" to see if it worked.

Hydro pH should be between 5.6 - 6.3 and 5.8 to 6.2 is prime after the res gets pH "stable". There will be a "swing' so start the pH low at like 5.7 and let it rise to no higher then 6.2 and readjust it down......The pH "swing" will mimic natural pH swings in nature/soil that supply nutrients that are available at differing pH values!

Now then, WHAT nutes are you using and list EVERYTHING that gets mixed in!
What is your pH?

We can get this sorted out!

Thanks guys for help. I started adding Cal/mag into feeding and it's already started showing sings of improvement. I just wonder why the Epson salt didn't help. Maybe it's as useful as milk as calcium replacement....

because epsom salts is magnesium sulfate, for magnesium or sulfur deficiencies, no calcium in it

check this out, guide to a lot of common deficiencies
http://www.growweedeasy.com/cannabis-symptoms-pictures