any ideas??

We need all the info on your grow including:

What type of medium; soil or hydro?
What brand and type of soil?
Indoors or outdoors?
What strain?
How old are the plants?
What type of lights and how many watts?
How far from the lights?
What is your watering frequency and source of water?
What, how much and when was it fed? NPK?
What is the medium/runoff pH and PPM if in hydro?
What are the temps and humidity in the room?
What size pots?
Any bugs? Look real close.
Any other pertinent info?

If any of these questions have already been answered please disregard as I cut and paste this for everyone.

If there is leaf discoloration please TAKE PICTURES WITH ALL GROW LIGHTS OFF, ESPECIALLY HPS & LED's. Taking pictures and taking them with lights off, allows us to see what the leaf discoloration looks like.

 

Friend, you're going to have to give more information if you want help. That's what we're here for. Do you not want to fill out the form? Are you phing your source water? Isn't Pro-Mix considered a soil-lees substrate? If it is you should ph the rootzone at 5.8... irregardless, perhaps you can supply us more info, huh?

 

Okay, went to investigate Promix and seen it is precharged with lime, but you've driven the ph of the root-zone down with excessive amounts of fertilizer. The pix in the original post are indicative of Ca and Mg with Ca being the overriding deficit. Have you flushed?

 

I wouldn't necessarily consider it soil-less since it comes precharged with lime, you should treat it as soil. I only made reference to soil-less because I thought it was also. Ph at 6.5/6.8 Sometimes if you don't flush enough, ph run-off will not change, but you may notice marked improvement in a few days. Be vigilant.

 

Been thinking about what you said about the Cal-Mag, using it every time you water? Beats me bud, I've never used the stuff. Depends on many other factors... we know already the root-zone ph is low, I can only imagine that adding Cal-Mag each water through certainly didn't help. 

 

 
What was the ph run-off on the fresh batch?

 

That's not good, sorry to hear. You need to get some ph up and dolomite lime, or do a transplant into some fresh soil besides Promix. What say you?

 

Yea, the lime needs time, and is slow to react. I've used baking soda from time to time, but don't really advocate it's constant use, but have never seen any adverse reaction to a one time application.

 

are you using well water, city water or? is it filtered?

 

Another dude is using Promix and having problems also. I'd get away from that mix next grow.