Im confused! pH problem

Hello guys

I'm a new grower and I'm having some problems with an autoflower that's mid bloom. I grow with Plagron all grow soil and use Bio Bizz nutes.

My plant is showing signs of nutrient deficiency (yellowing leaves, purple edges) but also shows signs of over feeding (burned tips of leaves). Now I'm thinking its a pH problem, but on the Plagron site it says pH shouldn't be an issue with their soil..
So I measured the pH of my runoff after watering (pH 6,2) and it measures 6,9.
I tried watering with pH 5,8 this week but I can't get the pH of the soil down. The plant is also getting worse.

What am I doing wrong?



(can't get pictures atm)

jasperr said:

Hello guys

I'm a new grower and I'm having some problems with an autoflower that's mid bloom. I grow with Plagron all grow soil and use Bio Bizz nutes.

My plant is showing signs of nutrient deficiency (yellowing leaves, purple edges) but also shows signs of over feeding (burned tips of leaves). Now I'm thinking its a pH problem, but on the Plagron site it says pH shouldn't be an issue with their soil..
So I measured the pH of my runoff after watering (pH 6,2) and it measures 6,9.
I tried watering with pH 5,8 this week but I can't get the pH of the soil down. The plant is also getting worse.

What am I doing wrong?



(can't get pictures atm)

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Cant diognose without pics.

Could be over feeding.

Cant tell. But your ph is probably fine


Whats your temps and humidity .

The manufacturer suggests 1) rinsing out beforehand to rinse out unabsorbed nutrients they added and 2) nutrition is needed after 6 weeks.

Did you pre-rinse the medium before using It?

They recommend their 2-part nutrients but probably any line do.

hotrodharley said:

The manufacturer suggests 1) rinsing out beforehand to rinse out unabsorbed nutrients they added and 2) nutrition is needed after 6 weeks.

Did you pre-rinse the medium before using It?

They recommend their 2-part nutrients but probably any line do.

Click to expand...

I watered it down once, not like a big flush or anything like that
But at the veg state the plat is looking perfectly healthy, i only started feeding a week into flower since the leaves started to lose the dark green color. Then came the problem of over feeding while still having nutrient problem (at least T think)

Without pics it's just guessing on our part. The dark green was probably from high nitrogen and as your nitrogen was utilized from the EWC the color started to show as "normal" in shade is my guess. Feeding then might have pushed it a bit. Ride it out.

projectinfo said:

Cant diognose without pics.

Could be over feeding.

Cant tell. But your ph is probably fine


Whats your temps and humidity .

Click to expand...

I had the yellow leaves before the over feeding signs. I'm pretty sure I overfed them but I don't know what else to do but feed more nutes

My grow tent is in my garden shed since that was the only possibility, but it means it's hard to control temp and humidity. It has been super hot these past weeks so my temp is around 27°C till 33°C, my night cycle is 4 hours which is on the hottest part of the day. But this is pretty abnormal and should be over soon, which would keep it around 25°C
My humidity goes from 30% to 70% depending on the weather, but I never had problems with mold.
I have a 190 m³/h outtake fan and passive intake and a good fan that's at the bottom of the tent blowing to the buds at my led light, which gives a bit heat from the top

I will try to make a picture at the end of the week, don't really have a camera or smartphone atm

Humidity is important as well indoors.

For veg 70%
early flower 60%
Mid flower 50%
End of flower 40%

The humidity is what decides how much your plant will feed through their roots

Because if the humidity is low it makes a negitive pressure on the stomata under the leaves down to the roots sucking up water/food.

If humidity is too high they wont suck up any water/food through their roots. This is important when their young because young plants dont have many roots and need to feed through their leaves instead.

Fix your humidity problem and get back to us

Also google vpd chart. And live by it.

Everest fernandez on youtube made a great little video explaining vpd charts. Of youd like more info on the subject

Aight thanks for the info!

But how can I lower my humidity?
I only have a 2x2 space, and I'm pretty much dependent of the weather for humidity (pretty humid in Belgium), I can only put a bowl of water to increase humidity right?
I don't see a dehumidifier fitting in that space with a plant + it's really expensive

Until I find the problem, do I still feed the plant or just give water?

When did you start feeding nutrients?

coreywebster said:

When did you start feeding nutrients?

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Around 5 weeks, 1 week into flower
When the plant was starting to become light green

I don't suppose you have an EC meter?

Could be its overfeeding and lock out. But its a guess without pics.

What you call burnt tips we might call something else.

There are burnt tips from too much food and there are similar symptoms from phosphorous def or potassium def.


Best bet for you been unable to provide pics is to have a look on here .
https://www.growweedeasy.com/marijuana-symptoms-pictures

From the pictures it could be an iron or zinc deficiency, light burn or over feeding, I'm actually starting to doubt the overfeeding and start thinking it's light burn
I don't have an EC meter, only pH

I put my lights a bit higher a few days ago, but the damage is irreversible right? Do I just keep feeding my nutes now?

I'll have some pictures in a few days

I'd try keep it below 30°c but like you say it's been hot. without looking I'd say take them out get some clean water or even a flushing addative raise them off the floor and let a few gallons pass through them. then feed them via the leaves with 1/4 strength feed try find something with iron in it. only reason Im saying this is I've just been through the same thing all due to heat. is there plenty of air coming in as there is going out too. and air circulation movement reduces hot spots is there an oscillating fan? I also invested in some plagron green sensation and the girls have made a massive turn around and I mean MASSIVE. I also had spider mites due to the dryness gone now tho.

vitalink also sell an addative for temps that exceed 30°c

jasperr said:

Around 5 weeks, 1 week into flower
When the plant was starting to become light green

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Thye get a lot light green in color as flowering starts. You probably didn’t have any problems at first except a little overfeeding, which is the tips.

Light burn was going to be part of my guess, then I read your last post. Leaves will produce purple pigment (anthocyanin) to protect against too much light, so that was my clue.
You have ride it out, buddy, that’s all you can do other than start over. Good luck with heat management, if you cannot cool it off do what you can to raise humidity.

Michael Huntherz said:

Thye get a lot light green in color as flowering starts. You probably didn’t have any problems at first except a little overfeeding, which is the tips.

Light burn was going to be part of my guess, then I read your last post. Leaves will produce purple pigment (anthocyanin) to protect against too much light, so that was my clue.
You have ride it out, buddy, that’s all you can do other than start over. Good luck with heat management, if you cannot cool it off do what you can to raise humidity.

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I put my quantum board at 40cm now (instead of +/- 25) and my top leaves are starting too look a bit green again, some bigger leaves died off though. The weather is OK again, a bit humid but temp is between 23 and 28 now in the tent. The plant overal looks pretty yellow but the buds are looking good and are fattening, going to flush soon.
Does this mishap (over feeding, light burn) affect the buds in any way btw? Like does it change the potency or taste even if they still look good and I flushed and cured them good?
Is it safer to just go for feminized plants in the future so I can give her more recovering time?

led+cmh+hps#user said:

I'd try keep it below 30°c but like you say it's been hot. without looking I'd say take them out get some clean water or even a flushing addative raise them off the floor and let a few gallons pass through them. then feed them via the leaves with 1/4 strength feed try find something with iron in it. only reason Im saying this is I've just been through the same thing all due to heat. is there plenty of air coming in as there is going out too. and air circulation movement reduces hot spots is there an oscillating fan? I also invested in some plagron green sensation and the girls have made a massive turn around and I mean MASSIVE. I also had spider mites due to the dryness gone now tho.

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There is a fan blowing at the buds and the temp is under control atm.
I started to use Biobizz top max and bio heaven and they look pretty good now, would this be similar to the green sensation? I don't want to mix up too many brands.
Btw, would a calmag additive help in this case? I read about it somewhere it helps with LED lights

jasperr said:

I put my quantum board at 40cm now (instead of +/- 25) and my top leaves are starting too look a bit green again, some bigger leaves died off though. The weather is OK again, a bit humid but temp is between 23 and 28 now in the tent. The plant overal looks pretty yellow but the buds are looking good and are fattening, going to flush soon.
Does this mishap (over feeding, light burn) affect the buds in any way btw? Like does it change the potency or taste even if they still look good and I flushed and cured them good?
Is it safer to just go for feminized plants in the future so I can give her more recovering time?

Click to expand...

It will mostly have an effect on yield, though I underwatered a plant real badly one time and I feel it impacted the potency too, don’t worry about it for now.
I would skip the flush and feed lightly until harvest, because you say she looks pretty yellow, flushing will increase that and really impact your yield. Yellow leaves is usually N deficiency, but many strains yellow-out toward harvest regardless.

Flushing pre-harvest to “rinse the nutes out of the buds” or whatever people think is happening is bullshit, All you’re really doing is slowly killing the plant and starting the curing process a little bit early. It hurts yield and it doesn’t help quality. Curing is the key to quality nugs.

I made some quick pictures today with my camera camera

She looks hungry to me, how many weeks into flower?

Also, I think your light is a bit too close, I see signs of light burn.
(Nevermind, I see you did that. Maybe give it about 45cm, I go 24” but I am running 570 actual watts total...)
Give that bitch some nitrogen! And get an oscilating fan in there, I didn’t notice one.