Help please - Gorilla Bomb

coralman

Well-Known Member
So I have 4 gorilla bomb in biobizz all mix under 750w light 1mx1m Scrog.

The bottom right plant is having problems as you can see by the pictures.

Currently in 6th week being fed on 3ml bloom. 4ml grow. 1.5ml ok boost and 2ml algamic and last watering had tbs per gallon of Epsom salts. My soil ph is 6.8.

At first it showed signs of underfeeding and now it has burnt tips which has thrown me. It's a 10 week strain.

Any suggestions the other 3 seem fine

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First you need to calibrate that soil pH meter.

To calibrate the soil pH meter:
  1. Place soil pH meter on a sturdy surface. A concrete sidewalk is best.
  2. Using the heaviest hammer you can find, hit the soil pH meter with all your might.
  3. Gather and dispose of the pieces of the soil pH meter.
  4. Buy a real pH pen and a bottle of pH 7.0 calibration solution. (I use General Hydroponics brand.)
  5. Place tip of pH pen in calibration solution.
  6. Adjust calibration screw until meter reads pH 7.0.
  7. Repeat weekly.
  8. Keep glass bulb of pH pen immersed in calibration fluid for maximum service life.

That yellow plant has some serious chlorosis and needs immediate attention.

I would suggest looking up the nutrient schedule for the nutrients you are using and then mixing up a batch of nutrients in the exact proportions that they recommend for the flowering week you are at, only 1/2 strength.

Do not add anything else. (I mean just use the basic 2-bottle or 3-bottle solutions without a bunch of extra stuff. Trust that the soil scientists at the fertilizer company know what they are doing and their basic NPK + Micros formulation is enough for a successful grow.) Throw away the Epsom salts. If you see evidence of a calcium/magnesium shortage, add a cal/mag supplement. (I use GH CALiMAGic, but I suspect they're pretty much all the same.)

Good luck!
 
I'm stumped haha had so many successful grows the only thing different is I have more wattage/lumens per square foot. Feeding soil additives etc... are all the same. Could be strain related. The leaves have a sort of purplish tint in them which I thought could be deficiency of some sort which is causing the problems? I'm just brainstorming now though. The other 3 are fine though which stumps me even more.
 
Mate that's a ph probe cost a bomb. It's not the cheap shit. Also I have ph pens but they arnt really suitable to check soil ph at the roots

Sorry, CM, but that type of meter is worse than no meter at all. I think you'll find that that's a universally held opinion around here.

To read pH with a pH pen, water to 10% runoff (e.g. 100 ml after adding a liter) and measure that.
 
Sorry, CM, but that type of meter is worse than no meter at all. I think you'll find that that's a universally held opinion around here.

To read pH with a pH pen, water to 10% runoff (e.g. 100 ml after adding a liter) and measure that.
If it had an LCD screen would you think different? It's been good to me so far and seems more reliable than the pens with run off. Maybe invest in a more expensive probe as a lot of articles iv read sway towardst testing ph directly at the roots.

I will check the run off though and see as I'm just going on my past experiences and what iv studied. Thanks
 
I'm stumped haha had so many successful grows the only thing different is I have more wattage/lumens per square foot. Feeding soil additives etc... are all the same. Could be strain related. The leaves have a sort of purplish tint in them which I thought could be deficiency of some sort which is causing the problems? I'm just brainstorming now though. The other 3 are fine though which stumps me even more.

I stand by my original recommendations. Just feed basic NPK + Micros at 1/2 recommended strength at the exact proportions that the manufacturer recommends and don't add anything else. Trust the people with the graduate degrees in agronomy and laboratory equipment to get the formulation right without a bunch of extras. When things are going wrong, getting back to known good nutrient dosing is a great first step.

The other three actually look a little chlorotic to me--those leaves could be much deeper green.

I'm concerned, too, that whatever organic pH adjuster you're using + that whack pH meter means your pH is somewhere way off... "Inorganic" pH adjusters have nutrients that your plants can use and work great. Why not go with those, too, until you get past this rough spot?
 
If it had an LCD screen would you think different? It's been good to me so far and seems more reliable than the pens with run off. Maybe invest in a more expensive probe as a lot of articles iv read sway towardst testing ph directly at the roots.

I will check the run off though and see as I'm just going on my past experiences and what iv studied. Thanks

It looks like you're pretty sure that what your doing is the right way to go so I'll stop trying to convince you otherwise. Good luck!
 
Measure pH directly in soil or from run-off water?

Fuzzy ducks replys

"
Run off seems not very accurate to me as the water/nutrients has just been leached through an enitre flower pot... some of those nutrients will stay with in the soil whilst the run off may pick up excessive salts which may well give you total differnet PH reading than that of the soil..."

Anyway enough of the which is best too test ph as everyone has different ways of doing it. What the hells up with my plant hahaha
 
Anyway enough of the which is best too test ph as everyone has different ways of doing it. What the hells up with my plant hahaha

I've gotta take one more shot at this. ;) My best guess is that all of those plants are short on nitrogen and thus chlorotic to varying degree and one to an alarming degree.

It's hard for me to decipher the shorthand descriptions of what they've been fed, but if it's high PK or worse exclusively PK bloom nutrients with little or no nitrate, that might explain it. I only focused on the pH meter because that type of meter has a well established reputation for giving erroneous results and because the extent of that chlorosis is so remarkable, it seems likely that something is really out of whack.

Here's a link to Jorge Cervantes's famous but too-often misinterpreted nutrient chart:
https://loudclouds.co/wp-content/uploads/2016/07/marijuana-deficiency-chart-jorge-cervantes.jpg
 
So thank you everyone for the replies. I think that pheno is a bit sensitive to nutes as all the others are still fine and I have laid off on nutes on the sick girl and she hasn't got any worse than before so just keeping an eye on her. Thank you all again
 
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