Brown/Greyish spots on leaves, pH etc

Hi Guys,

Sorry, no pics.. but it's pretty easy to explain. My Blue Cheese (soil) is showing brown greyish spots on her lower leaves. I looked up a few guides and some say Calcium Deficiency others say PH Fluctuations. I have it in a good soil mix and I PH all my water when I have too. It changes at times.. lately it's been around 7-7.5. I know PH fluctuations are bad.. but what is too big of a fluctuation? Sometimes I get it to 6.8-6.9.. other times its 7.5 at most. Is that too much?

Thanks!

It pays to try and keep as close to 6.8 as possible, a little fluctuation in soil is fine because of the way soil holds its pH. Tell us a bit more about your setup, and your feeding/watering techniques?

in soil you should keep the ph between 5.8 to 7.4.
outside that range major deficiencies will show.

the PH check should be done in the soil - thats what the plant is getting and that is what's important.

getting a ph of 6.3 instead of the recommanded 6.0 for coco for a week wouldn't do much at all. And coco is way less forgiving than soil.

PH is over-rated in soil\soiless grows.

Thanks for the help. I have a 400W MH on a couple plants, but the Blue Cheese is the only one having problems. I just checked again and lower leaves are yellowing a little bit. They are about 1/5 Months old but been severely topped/LST/ed.. so its a MEGA bush in 3 gallon pot and only about a foot tall. I have only given it 1/2 strength technaflora's recipe for success once, did a normal water, next will be a full dose. What other info would help me figure out what it is?

what medium do you grow in?
how often do you water?
with what kind of water?
at what PH?
do you apply foliar feeding?
what are the temps and humidity?
What is the size on thoes brown\gray spots?



lower leaves turning pale is usually a sign of N deficiency. Either your plant have too much P and K it locks the N, the PH is shifting so much the N gets locked or simply there isn't enough N in the medium readly available for the plant.