[DR0ck]

Hey gang. I've got this cherry pie auto she's been doing very well in FFOF. She did get a dry bud and bloom booster a 5sh weeks ago. Still some flowering time left (she is just entering 6th week of flower) so I want to figure this out. I'm a new grower but I think this is a little strange. She's getting yellow near the top and also some older larger fan leaves about midway. I wonder if light exposure has something to do with it because her bottom is still forest green looks pretty good. Also some brown spots here and there. This one leaf (pictured) is getting pretty yellow and starting to curl. I wonder if the nutes are running out. I did just start some calmag because some of the brown spots to me look like calcium deficiency.

 

[Ninjadogma]

Middle and upper plant leaf yellowing is how high soil EC rears it's ugly head. Make sure you're pushing enough water volume at your watering and feeding events to carry out any excess salts that have accumulated. Secondary to that, make sure the pH stays in a good range. If it has drifted up it can cause leaves to appear nutrient deficient.

 

[DR0ck]

Middle and upper plant leaf yellowing is how high soil EC rears it's ugly head. Make sure you're pushing enough water volume at your watering and feeding events to carry out any excess salts that have accumulated. Secondary to that, make sure the pH stays in a good range. If it has drifted up it can cause leaves to appear nutrient deficient.

Always water to runoff then? I had dialed volume back a bit (still dropping 2L twice a week) because I was overwatering originally. She takes the 2L fine and is plenty heavy after but not always a ton of runoff.

 

[Ninjadogma]

You'd be surprised how much runoff you're really aiming for. You're looking at cycling somewhere around 10-20% of the pot size, so if you're in a 5 gallon you want to see between a half and full gallon of water slowly moving out after being slowly moved in. Until you get a knack for it, it's not a bad idea to stick a ln EC pen in your runoff so you can see how it drops, and how sometimes it's stubborn about dropping.

 

[GNick55]

just makesure the medium is soaked, no reason to have run off maybe a little to know you’ve watered completely,. than let it dry out before watering again
what light you got and how close is it?
what kind of nutrients do you have there?

 

[DR0ck]

just makesure the medium is soaked, no reason to have run off maybe a little to know you’ve watered completely,.
what light you got and how close is it?

The top of the plant is close it's about 6 inches. I've got some compromising going on I have a few other younger plants in there too so that's why it's a little close to this one. But this plant's yellow leaf from its midpoint (plenty of green above it) is more than the manufacturers recommended distance at this intensity. It is an older fan leaf though. Vivosun aero light wing AW200SE.

 

[GNick55]

The top of the plant is close it's about 6 inches. I've got some compromising going on I have a few other younger plants in there too so that's why it's a little close to this one. But this plant's yellow leaf from its midpoint (plenty of green above it) is more than the manufacturers recommended distance at this intensity. It is an older fan leaf though. Vivosun aero light wing AW200SE.

ok so definitely light stress,
and what looks like a watering issue, not watering enough correctly,.
like a 5 gallon bag would take 1 gallon of water that you would give say a 1 litre at a time 4 times but with 10 mins or so between the waterings also making sure to cover all the medium,.. and than don’t be afraid to let it dry out before watering again

 

[DR0ck]

ok so definitely light stress,
and what looks like a watering issue, not watering enough correctly,.
like a 5 gallon bag would take 1 gallon of water that you would give day a 1 litre at a time 4 times but with 10 mins or so between the waterings also making sure to cover all the medium,.. and than don’t be afraid to let it dry out before watering again

Thanks. I had already dialed the intensity back a bit (I had increased it relatively recently too) but I'll move it back further. And my next watering I'll be sure to hit a little runoff to make sure it's enough and I want to measure the TDS against my watering TDS just to see if there's a ton of salt coming out.

 

[GNick55]

Thanks. I had already dialed the intensity back a bit (I had increased it relatively recently too) but I'll move it back further. And my next watering I'll be sure to hit a little runoff to make sure it's enough and I want to measure the TDS against my watering TDS just to see if there's a ton of salt coming out.

sounds like a plan!
keep us updated

 

[DR0ck]

sounds like a plan!
keep us updated

I think I found the issue! Input pH was 6.8-6.9. TDS is fine.

 

[Ninjadogma]

I think I found the issue! Input pH was 6.8-6.9. TDS is fine.

I would suggest getting a little bottle of GH pH drops instead of relying on a pen. They're notorious for losing calibration and you can wind up working with values you think are good according to the stick that are actually horrible. If you know the value of your tap, it's not a bad idea to use it to spot check your calibration. I use a pen to get a rough idea like checking runoff, but when accuracy matters I'm using drops.

 

[DR0ck]

I would suggest getting a little bottle of GH pH drops instead of relying on a pen. They're notorious for losing calibration and you can wind up working with values you think are good according to the stick that are actually horrible. If you know the value of your tap, it's not a bad idea to use it to spot check your calibration. I use a pen to get a rough idea like checking runoff, but when accuracy matters I'm using drops.

Thanks I'll get those drops.
I added a little bit of dolomite lime and one of my plant's posture has already improved. I'll keep monitoring I hope I've zeroed in on the issue.

 

[Glomus]

I think I found the issue! Input pH was 6.8-6.9. TDS is fine.

Im dealing with the same thing rn, Dolomite is the fix. And a slightly higher input ph.

 

[DR0ck]

Im dealing with the same thing rn, Dolomite is the fix. And a slightly higher input ph.

Do a slurry test it is more accurate. Mine turned out to be 6.4 which is fine. I'm just feeding now. Didn't realize that FFOF runs out I thought it was supposed to supply the full run of an auto.

 

[Glomus]

Do a slurry test it is more accurate. Mine turned out to be 6.4 which is fine. I'm just feeding now. Didn't realize that FFOF runs out I thought it was supposed to supply the full run of an auto.

When the nutrients that act as a buffer and the ph buffer in the soil gets depleted the ph of pete does naturally swing down to low 5s. Dolomite doesnt hurt because it nutralizes around 6-7 so you cant really burn with dolomite. the only issue with dolomite is maybe too much mag sometimes. Im using rain water so I really have to watch my ph swings. After alot of run off my ph is still low so I'm slowly correcting it, Im have mag and maybe a little cal deficiency too so I know its the PH.

 

[Glomus]

Do a slurry test it is more accurate. Mine turned out to be 6.4 which is fine. I'm just feeding now. Didn't realize that FFOF runs out I thought it was supposed to supply the full run of an auto.

Honestly your EC is probably more important then the sil ph runoff. If your EC looks good then you can feed normally.

 

[Glomus]

Thanks. I had already dialed the intensity back a bit (I had increased it relatively recently too) but I'll move it back further. And my next watering I'll be sure to hit a little runoff to make sure it's enough and I want to measure the TDS against my watering TDS just to see if there's a ton of salt coming out.

Could be too much light too fast as well, they want a gradual increase as flowering progresses unless your pumping CO2

 

[Blimburnseeds]

I think I found the issue! Input pH was 6.8-6.9. TDS is fine

That's the problem, more than the pH. To fix it, you need to water with a solution with a lower pH, 5.5, for 7-10 days.

 

[DR0ck]

That's the problem, more than the pH. To fix it, you need to water with a solution with a lower pH, 5.5, for 7-10 days.

You are telling me to lower my irrigation pH further?
I think that's wrong. My slurry pH was 6.4. The runoff was under 6. Not sure how you are arriving at that conclusion.

 

[Blimburnseeds]

You are telling me to lower my irrigation pH further?
I think that's wrong. My slurry pH was 6.4. The runoff was under 6. Not sure how you are arriving at that conclusion.

At pH 6.5 and above, the absorption of micronutrients like calcium, magnesium, and iron, which seems to be what the plant is lacking, begins. If you consistently water with that pH, the soil will become too acidic, and you'll need to lower it. After a few days of watering with a lower pH, it will reach 5.7 or 6, allowing the roots to absorb nutrients more effectively.