Rust Spots Turning Into Brittle Yellow/Brown Leaves.

Does molasses have enough cal/mag to fix the problem? I am havinng the same issuses.

its ph problem

To high or to low cuz my ph was close 7 if not 7.

Wow... A lot of people here seem to think they know wtf they are talking about with their diagnosis. 420 God is the only one with the reasonable approach, and he offers a solution rather than just a name to the problem.

The reason most people here are struggling is because there is just so much wrong.

There is most definitely a pH issue. I question the accuracy of your measuring device if your pH is infact 7.0. Your meter may need to be calibrated or replaced with an upgrade.

The rusty brown spots 99% of the time are referred to as pH spotting and it results from an acidic media locking out elements like calcium, magnesium, and potassium. Low and behold. Those are the elements listed in this discussion. So we're not far off in the diagnosis. Yes the plant is deficient... but not as a result of an under-abundance of elements in the soil. It is actually quite the opposite.

In addition to the pH issue, there is a contributing heat issue (86 degrees is not okay). Heat causes increased rates of transpiration, which utilizes elements like potassium to mobilize energy for the procedure. This then exaggerates the potassium situation, ultimately creating a domino effect.

The use of Sphagnum Peat Moss based Happy Frog Soil indicates to me that it is likely a conglomeration of issues that all started with a pH imbalance and a heat problem. These will ultimately cause more problems and you're knee deep in the thick shit right now.

Identified the problem. Now for the solution.

Start with the easy stuff. Back the light off to 18" to 21" from the plants. This will reduce canopy temperatures and the load on the chlorophyll. Think of it like driving a little less "lead footed." If your plant is a car, then you are low on gas because you've had the pedal to the metal. It is a good idea right now to slow down to 55mph and get that efficient mileage so you can make it to the next gas station.

Reduce the heat in the room. Get an AC, leave the window open. Do whatever it is you have to do to keep your temperatures under 82 and ideally around 75.6 to 76.2 all day every day. Night time temperature swings, from 80 during the day to 60 at night, is not beneficial.

You need to flush the media to balance the pH. Using a 6.8 to 7.0 pH solution run at least 2 gallons of water through the media (after saturation) to get the system back in balance. Once the media has been flushed and the run off pH is dialed at over 6.5 but beneath 7.0; then you can rebuild your nutrient buffer. Using 1-2ml per gallon of your macro system from H&G make a nice low strength solution. If you have some cal-mag around 1ml per gallon of that would be fine to add around 20ppm of the stuff to your system, not a lot, but enough to keep the plant from leaching more elements in a "reverse osmosis" fashion back into the media in order to balance out electrically. (Plant=high pressure nutrients / Flushed media=low pressure nutrients / Pressure flows from high to low).

Once the temperature is resolved, the light backed off, the media pH and CEC balanced... Then you can take a week or so to let the plant rebound and make your follow up treatment based on the current issues with the plant. You do need to drop your ppm levels in the future. 1000ppm in soil is ridiculous. If you want to feed like that then move into coco. 500ppm to 800ppm is a good range for most strains.

Good luck dude. Work on your environment before you get this far with another grow. Better to have everything dialed in.

I'll go check my runoff now and flush if it's off. How close should my run-off be to what I put in?

Right now... You want that shit dialed perfectly. What goes in should be almost exactly what is coming out.

Ultimately it is going to be different. Can't be exact. But you want to be as close as possible.

The run off is a little over 5, flush?

Pimpernickel said:

The run off is a little over 5.

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There you go!

Build up of salts in the media probably contributing to the low pH as well.

Think of it this way. If the soil was a 3 and you added some 7 then the middle of that would be 5. To put it another way, your media is more acidic than the run off... You are WAY acidic right now, probably as a result of some salt buildups.

You're going to really need to flush this plant. I'd do 5 gallons at a time, every 20-30 minutes, as many times as it took until the water runs out nearly clear and the run off pH is back in range.

I`m glad an expert tookover.

Goodluck Pimpernickel!

Tricks said:

I`m glad an expert tookover.

Goodluck Pimpernickel!

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Me too! I flushed each plant with 2.5 gallons, which is all I could fit, four times. I had to use water from my old dechlorinator/sediment filter because my RO system doesn't put out enough water. I finished an hour past lights out. I'm going to give them some Green Magic foliar feed in the morning, hopefully everything goes well. This is my third grow and it's allready looks bigger and better than my second. I have two issues to solve, I'm picking up a A/C in the next week or two for my temps. Then I need to figure out this lockout problem, I'll start by lowering my base nutes by 25%. I am still confused as to why my biggest and best plants are the most afflicted with this problem though.

Thank you very much Snow

I hven't seen any real changes same shit is still f'd and spotted, som eof the lowers are yellowing and flaling off. The folier which was Magic Gree3-.1-.4 didn't do much or pretended incoming problems unseen.

The plants aren't going to "heal." What is brown is dead, and you haven't seen the end of the problem for a while. The yellowing you are seeing could be a leaching of nutrients, but you need to really give this plant time to recover from the stress of the acidic media. It might take a week before you see the problem really stop and good green vigor return. Soil issues are slow in both regards, starting and stopping. Just take it slow, stay the course, and maybe toss a really light feeding with plenty of run off the next time the soil goes dry. Keep that pH in check and this little hiccup with be nothing but a memory by harvest time.

either magneisium or calcium, they look allot alike cantremember. just get some Cal/mag. use every grow.. Pe@ce.

The problem has stopped spreading for the most part. Some of the leaf sets that were affected did still die completely. There are a few new leaves at the tops of the buds that look good. A few of the plants started to yellow a bit so I'm going to give them a feed today, I'll go 75% of normal base nutes.

cannabisguru said:

here, here's a nice chart for everyone to check out. Not sure how accurate the chart is.. but its def. a good chart IMO. But again, as for the accuracy of it.. not sure on that.. because I didn't create the chart. But here it is.. if anyone wants it.

View attachment 1498834

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Nice Chart Cannabisguru, VERY helpful thank you.

The deficiency problem ended up hitting all of my larger plants while not hitting the smaller plants. I talked to a tech from House & Garden, he didn't seem concerned with the pH drop in the run off, based on that and my thoughts that the larger plants get hit because they aren't getting what they need I've doubled my feed rate. I now feed 2 gallons of standard strength mix nutes each week instead of one. I'm in my second week of flower in my next grow and haven't seen any of the signs of deficiency I saw in my first three runs. I got an air conditioner to solve the heat problem.

i know this thread is old but i just went through the same shit... on my last two grows. thanks for all the info... I will be trying out the same solution

Snow Crash said:

The plants aren't going to "heal." What is brown is dead, and you haven't seen the end of the problem for a while. The yellowing you are seeing could be a leaching of nutrients, but you need to really give this plant time to recover from the stress of the acidic media. It might take a week before you see the problem really stop and good green vigor return. Soil issues are slow in both regards, starting and stopping. Just take it slow, stay the course, and maybe toss a really light feeding with plenty of run off the next time the soil goes dry. Keep that pH in check and this little hiccup with be nothing but a memory by harvest time.

Click to expand...

hey I’ve seen u post some real helpful stuff. I’ve got a similar problem. But I’m growing in coco and pebbles! Is this still a ph problem if growing in coco