Slight spotting of fan leaves

So...Ive checked all the FAQ's, and symptom guides and all that...but my problem doesnt seem to be on any of those lists.

My plants are about 4 weeks into veg from clone. Its only the Blueberry strain, and only one plant is really affected, the other Blueberry is starting to show light symptoms.

Basically its like a yellow/brown spotting/speckling of the larger fan leaves. None of the newer growth is affected, and its only maybe 6 or 7 fan leaves so far.

I checked for pests, took my ph (6.5), and my nutrients are only at 1/2 strength so far.

Watering about every 4-6 days (letting soil dry out slightly before watering)

Im growing indoors, in FF Ocean Forest Soil. And im using FF's nutrient lineup.



Pay no attention to the tear in the leaf, i ripped a small piece off to look at it under microscope.

What type of water are you using?

Im using filtered spring water...sometimes mixed with a small amount of tap water.

Spring water ph is 6.7

Tap water is 7.0

I suspect a PH lock out of calcium at the moment and here is why: Mg and Ca get locked out from 6.5 and below. If one or the other lock out, they affect each other. While everyone says 6.5 is ideal for soil, I strive for high sixes in my runoff. If you are using 7.0 water and it reads 6.5 in run off, chances are you are below 6.5 in the soil. I made mistake of aiming for 6.5 run off and I locked out Mg in my plants.

I suspect your soil is aciditic. You could sweeten it a bit by top dressing with lime, about 1 tsp per gallon of pot size and watering with 7.0 water. I use pellet lime for a nice slow release. Most soils come with it, but it does leech and wear out with waterings.

Google Marijuana Garden Saver_Handbook For Healthy Plants PDF and grab a copy. check out Mg and a lockout and see if that fits with what is going on with the plants.

Below is a picture of a a deficiency that is more advanced that your plant. credit goes to the same sources cited above.

Hmm...i suspected a Manganese or calcium deficiency....Im taking readings from my soil, not the runoff.

I saw that it was a bit low on the affected plant (around 6.0)....After the second dose of nutes it seemed to go back up a little.

Then it went up to about 7, so i added a little bit of molasses to my next watering to bring it down to about 6.5-6.7.

I think ill keep it at around the 6.7 area from now on.