At a loss on this one... (with pics)

Hey guys,

Just noticed these interesting new patterns on a couple of my leaves. Seemed to only be concentrated on one plant at the moment.
Currently watering every 3 days with a mix of FF Grow Big and a dash of molasses. Room is lighted with one 600w HPS lamp and a couple 85w cfls spread around for filler. Temp in the room is a consistent 73 degrees, humidity however is unknown at the moment. Plants are in there 6-7th week of vegetative growth (sorry cant remember for sure).
Been doin' some research myself but I just cant seem to find anything that looks similar to the problem I'm having. Hopefully the pictures will suffice but the best i can say is the leaf space between the veins are turning a brown, almost greyish rust color. It is also on these same infected plants that some leaf sag tends to occur. However those that are not affected are quite peckish and lively.
Any feedback would help and thanks for your time.

what is the ph of your water?also..i wouldnt start chopping off leaves tilll they are completely dead.

djruiner said:

what is the ph of your water?also..i wouldnt start chopping off leaves tilll they are completely dead.

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I agree.

While every grower should know the Ph of the liquids their plants receive, checking the Ph of the soil is even more important (if you're using any). If you don't have one already, try to get ahold of a soil Ph tester. It's a good idea to get one probe-type soil tester and one capsule-type or similar test kit to verify the probe's accuracy once in awhile. Be sure to save the receipt of any probe tester.

As far as pruning goes, if you remove damaged leaves before fixing the cause then future damage will just affect other leaves. Whether it's from Ph lockout or not, your plants are nutrient deficient and are drawing what they need from older leaves. The browning between the veins is a common symptom of Magnesium deficiency. The yellowing and any other problems are probably caused by something else. Nutrient lockout from incorrect Ph could cause all of this. Even so, after checking and then adjusting the Ph if necessary, it would be a good idea to give them some extra Mg.

Whole plant pics are always helpful for diagnoses so we can see exactly where on the plant damage is occurring.

My bad I did forget to mention the p.h of the grow. We are rockin a soil medium and I do in fact have a p.h. meter. I shoot for a p.h. of 6.3-6.5 every time i water. Ill look into gettin a soil ph tester in the near future though.
Ill roll with the Magnesium def theory for now, got some epson salts already at the house. Whats the best way to apply the salts? Just got some stuff I got from walgreens, would that be alright? Ill try to get some more pics up of the whole plant as soon as I can. Dont own a camera and my phone doesnt take the best pics ever as you can tell. Thanks for the quick responses!

6.3 is just a little too low for standard soil. Try not to let it go under about 6.5. I know it's only .2 but it can make the difference between healthy and not. Personally, I've never used Epsom Salts. For Magnesium, we mix Worm Castings into the soil and when they start to run out, we use Guano teas that provide plenty of Mg.

Cramos241 said:

My bad I did forget to mention the p.h of the grow. We are rockin a soil medium and I do in fact have a p.h. meter. I shoot for a p.h. of 6.3-6.5 every time i water. Ill look into gettin a soil ph tester in the near future though.
Ill roll with the Magnesium def theory for now, got some epson salts already at the house. Whats the best way to apply the salts? Just got some stuff I got from walgreens, would that be alright? Ill try to get some more pics up of the whole plant as soon as I can. Dont own a camera and my phone doesnt take the best pics ever as you can tell. Thanks for the quick responses!

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epson salts you use 1 tbls per gallon...but only use it when needed..they can get too much of a good thing...also to check your soils ph you can just test the runoff....as your watering...catch some of the water as it is running out the bottom..let it drain for a few seconds before getting a sample...ive used the soil tester and ive always gotten the same results with it as i did just checking the run off