Help! Brown spots

First timer with a 3 plant grow (BTW, ILGM seeds = 100% germination!) starting to see the leaves on 2 plants being to show signs of spotting before the spotted leaves begin to develop brown patches. My setup includes a 400w MH in ocean forest soil. I’m about 4 weeks into veg. I’ve been watering about once a week with ph’d water anywhere between 6.4-6.6ph. Each time I water enough so that there is enough runoff to fill a plant saucer (roughly 20% runoff). For nutrients, I have used them very sparingly (fox farm grow big)…about 1.5 mL. However, did this two waters in a row thinking the low dosage would be ok. The spotting is currently on the lower fan leaves only and not on all of them but afraid that it will start spreading up the plants. I topped and LST’d the plants two weeks ago and they responded well to that. Just not sure how to diagnose the new spotting.


I tried posting a picture but couldn’t get it to work…

However “Manning1017” posted a photo that exactly resembles my problem on January 19, 2015 @ 0643am (reply #28021). I wasn’t clear what the problem was (and how to correct) after reading through the follow up replies.

Thanks for your help!

I really do not know what to tell you aside from sating; When growing in soil, you need to know what you are doing. Using an organic rich soil and applying nutrients will possibly add too much of one mineral or another.

Please fill out a support ticket for a more educated answer. :slight_smile:

Take that 20% runoff and test it for TDS/PPM and pH. Maybe even start with only letting only 5% or 10% runoff build up and test it. Just enough runoff to test, say 3 oz. of fluid.

Test this and I bet it wont be reading 6.5-ish. Just because you are constantly watering or feeding with 6.5 pH doesn’t mean it will stay 6.5 at the roots. I suspect your spots are signs of a nutrient imbalance due to a pH that is out of range.

The total dissolved solids/parts per million test will show if you have too many nutrient salts built up.

You can also test for these as described by Robert in his new blog posting:

The only issue with that is; PH will not tell you how mcuh extra (too much) of one mineral or another is causing the problem. Correct PH, although one of the most importamt elements of growing, has nothing to do with applying an imbalanced nutrient solution to N-P-K soil

I would be testing the ph of the runoff water if I hadn’t made one big mistake when I was planting. I dropped in a 1 inch layer of gravel at the bottom of my pots and now all the dust from the gravel clouds up the runoff. I did it to help with drainage but now I am kicking myself (rookie mistake). I will try testing the ph anyhow to see if it will give me a sense of root-level ph. I don’t have a TDS/PPM meter unfortunately…its on my wish list :wink:

Thanks again for the quick replies…

I will also try Roberts method of testing root level ph from his blog entry

Thank you

For the future. I like the idea of an inch of gravel or rock, but you must always rinse it thoroughly before use. :slight_smile: Peace

You would be amazed of what dripped coffee grinds could do for your plants ?

PLease do not do this.

I won’t , I read that from Robert forum response , but you right I won’t do it , I’ll leave that to the professionals .

Can you up load a pic

Does it look like this