HELP. Problem getting worse every day.

I am in the fifth week of flowering and this problem has been going on that long. It starts in the veins and slowly progresses outward on the leaf finally turning into a rust. All of the plants are not affected, just a few. The ones affected are a Blueberry and two Afghan Kush.

Growing in soil, Fox Farms Ocean Forest. I was feeding with FF Big Bloom, FF Tiger Bloom and Beastie BLoomz but have since stopped and am only giving water. I use tap water but it is good well water. I found out that the PH of the water was getting lowered too much with the nutes. (to around 4). So now I am adjusting the water to about 6.5 without the nutes. They are under two 400W HPS lights and on a 12/12 schedule. I'm pretty sure that the low PH has done something. I don't think it's nute burn because it did not start on the tips but in the center of the leaves. If there is a nutrient lockout I don't know what it is because I can't find any pictures that look like these in any of the sick plant threads. I tried taking pictures of the plants but they don't turn out under the lights. So I took a picture of a couple of leaves. If you need I can try taking a picture after the lights go out.

Oh, I also tested the PH of the water coming out and it is two points lower than the water going in consistently on all the plants. Let me know if you need more info. I tried to think of everything.

Thank you very much for any help. It is greatly appreciated.

Ph levels is the only thing I can think of but I am still a newbie so get some other peoples advice too.

Good Luck!

Hey Doc. Thanks for the info. If it is PH I hope it will correct itself since I am watering with the correct PH now. I'm just worried that it is too late for the affected ones and there is another one starting. If anyone knows if I need to do anything to the soil let me know. I've heard that low/high PH can cause nutrient lockout. Thank you!

If I were you I would keep feeding nutes and buffer your ph after adding nutes. Iv'e heared that well water is quite soft so maybe you might want to add some cal mag. I think that once you get them back to there feeding routine and by ajusting the ph with the nutes they will recover.

Looks like pH fluctuation to me. I'd give it some no nutes for a couple of feedings and then give it full strength with properly adjusted pH.

Too much nutes, and soil pH is too low. You say you're adjusting pH to 6.5 in your water, and it's coming out of the soil two points lower? At 4.5?

Tap water is not pH buffered. That means you can have a gallon of it, add a drop of acid and the pH goes way down,.. versus staying the same. Your soil is probably very well buffered, meaning you add high pH water and it doesn't change much.

You need to get the soil pH up. Get some dolomite and dissolve about a cup of it in a gallon of water, not all of it wil dissolve and the pH of it is going to be really high maybe over 11. After mixing thoroughly on and off for an hour, let it settle. The next time you water add about a cup of this solution to a gallon of your tap, and pour it through your soil. Let it run out of the bottom, and repeat until the pH of the runnoff is over 6. preferably 6.5. If you overshoot, just flush another gallon through with regular water.

Once the pH is coming out at 6.5, capture the water and pour through again to make sure it stays at 6.5.

Then mix up 1/4 strength big bloom or something with potassium and phosphorus,.. Neutralizing your soil will take out most of the soluble nutes, and that's probably a good thing in your situation, because you may have overdone it, but you have to replace it with some nutes at the right levels,.. 1/4 strength will be good enought to keep things going. Water with the nutes solution at pH 6.5 until you get about a quarter to half of the volume of your pot running off. Fixing this will take time, so don't rush it. Let the plants drain between each dose of flushing, and if you use up the whole gallon of dolomite water before you're finished make up more. Be liberal with it, because if you don't get the pH of the runoff up, you're not fixing anything and expending this effort won't accomplish much but maybe rinse out some salt buildup from your nutes.

From here out, use no more than 1/2 strength nutes, and don't use more than one at a time, unless they compliment each other (are meant to be used together). For every other or third watering, add 1 tablespoon of blackstrap molasses (slightly acidic so pH it). You should see some health return before harvest.

Wow, Thanks Sidd. That was the answer I was looking for. I knew that the soil can get messed up from improper pH and too many nutes. But I wasn't sure what to do. I will try the dolomite. Not sure where to get it but the local hydro store should have it right? I have tried flushing with regular pH'ed water but the runoff didn't change. So I'm excited to give this a try. I LOVE this hobby. It's alot of fun, challenging, but fun. It's amazing how much you learn every day. Thanks again. I'll keep you posted.