Potassium Deficiency - or ?

[by2]

I think have a Potassium lockout or deficiency.
Problem started on older leafs and have moved up to newer growth.
One pheno showing more signs than the other 2.
Could it be something els?
What can I do in this case with what I have on hand?

Substrate - Cococoir/perlite
Pot size - 10l
Irrigation - tray2grow
Nutrient - RO water, greenhouse powder feeding short flower (0,7g/l), Calcium (1g/l), Boost (0,3g/l) - EC1,6/ph5,8 - following the schedule and the profile looks like this.

 

[Fish scale]

Yeah you've definitely got a nutrient deficiency going on there

 

[coreywebster]

Its generally recommended by autopot (least it used to be)
That you run considerably less EC than a drain to waste method to avoid salt build up.

I'd be running it 1.2EC and I'd guess by the timing you have a build up of salts causing lockout

I'd lift a pot and do a top feed to check run off and I'd guess it's going to be a lot higher than you're putting in.

 

[Wastei]

Like other people suggested you need to lower feeding strength if you only water/feed from the bottom. Lower feeding strength and feed more often solves most problems.

Looks like nutrient excess. You have plenty of K in that plant food. Never let the top surface dry out.

Cheers!

 

[by2]

Thank you all for the input.
I have lowered the EC to 1,2. 0,8g/l calcium , 0,4g/l short, 0,3g/l boost
Let's see if they will produce some buds this time.

 

[by2]

I will revive this thread even thou it's a new round of plants.
Same nutrient, Same irrigation.
I been feeding them 1g/l calcium and 0,6g/l short. EC1.18 PH5.9 since start of flower, they are on day 15 today.
Problem started on the lower leafs.
Should I raise or lower the EC and if so what part? The calcium is pure calcium so all other nutrient are in the short flower.
I was thinking to bump up the short to 0.8 to get a better ration of Ca to K. I could also lower Ca but 90ppm is not so much as far as I understand.
VS

Don't mind the water droplets. I just sprayed them with IPM spray.

 

[OneHitDone]

I will revive this thread even thou it's a new round of plants.
Same nutrient, Same irrigation.
I been feeding them 1g/l calcium and 0,6g/l short. EC1.18 PH5.9 since start of flower, they are on day 15 today.
Problem started on the lower leafs.
Should I raise or lower the EC and if so what part? The calcium is pure calcium so all other nutrient are in the short flower.
I was thinking to bump up the short to 0.8 to get a better ration of Ca to K. I could also lower Ca but 90ppm is not so much as far as I understand.
View attachment 5464513 VS View attachment 5464520

Don't mind the water droplets. I just sprayed them with IPM spray.
View attachment 5464514

View attachment 5464515

View attachment 5464516

View attachment 5464517

Is that correct that you have no Sulphur?
Some of the micro's look very low also.
I've been running a scratch mix that looks like this.



And getting growth that looks like this in aero/hydro

 

[by2]

Is that correct that you have no Sulphur?
Some of the micro's look very low also.
I've been running a scratch mix that looks like this.

View attachment 5464524

And getting growth that looks like this in aero/hydro

View attachment 5464525

Your plants look great. not even a burnt tip.

It should have enough according to GHF
this is what GHF states.
"Does Green House Powder Feeding contain Sulfur? A: Green House Powder Feeding contains a small amount of Sulfur and it is enough for the plant but is not obligatory to declare it on the label."

I could add the boost at 0.2g/l. It would bump up the micros and Mg a little. P and K would also be in better ratio.
Im new to all this with salts and PPM so trying to learn here.

 

[OneHitDone]

Your plants look great. not even a burnt tip.

It should have enough according to GHF
this is what GHF states.
"Does Green House Powder Feeding contain Sulfur? A: Green House Powder Feeding contains a small amount of Sulfur and it is enough for the plant but is not obligatory to declare it on the label."

I could add the boost at 0.2g/l. It would bump up the micros and Mg a little. P and K would also be in better ratio.
Im new to all this with salts and PPM so trying to learn here.

View attachment 5464526

We are all still learning even after several decades.
There is a lot of mis / dishonest info out here on nutrients. I'm still trying to unravel it all myself.
One thing for sure - these plants grow well under a wide range of nutrient profiles assuming all elements are provided at a sufficient level.
You could add a little Epson Salt to bump up your magnesium as well as sulphur.

 

[OneHitDone]

Your plants look great. not even a burnt tip.

It should have enough according to GHF
this is what GHF states.
"Does Green House Powder Feeding contain Sulfur? A: Green House Powder Feeding contains a small amount of Sulfur and it is enough for the plant but is not obligatory to declare it on the label."

I could add the boost at 0.2g/l. It would bump up the micros and Mg a little. P and K would also be in better ratio.
Im new to all this with salts and PPM so trying to learn here.

View attachment 5464526

To clarify, this is a bottom watering setup?
If so, I'd consider a heavy top down flush to reset the nutrient profile in the media.
The "butt chug" concept just keeps pushing things up in the media. Maybe you are accumulating phos/cal and other elements in the media over time and causing lockout of other nutrients.

 

[by2]

To clarify, this is a bottom watering setup?
If so, I'd consider a heavy top down flush to reset the nutrient profile in the media.
The "butt chug" concept just keeps pushing things up in the media. Maybe you are accumulating phos/cal and other elements in the media over time and causing lockout of other nutrients.

yes it is. I use the tray2grow from Autopot. 50/50 coco coir and perlite.
I will try and add some epsom salt to see if it improves. I will also spray them, so should see result pretty quickly.
I really don't want to reset the media since it would add shit load to my work flow over time. So will only use as last resort.
And in theory it should work since the system is built for exactly this and as long as I don't top feed the salt accumulation should stay on the top surface.

 

[OneHitDone]

yes it is. I use the tray2grow from Autopot. 50/50 coco coir and perlite.
I will try and add some epsom salt to see if it improves. I will also spray them, so should see result pretty quickly.
I really don't want to reset the media since it would add shit load to my work flow over time. So will only use as last resort.
And in theory it should work since the system is built for exactly this and as long as I don't top feed the salt accumulation should stay on the top surface.

Exactly - salts just keep twin pushed up in the media making bad zones for the roots.
Have you thought about doing a "Slurry Test" like a lot of organic growers are doing? Take a shot glass or so of your coco out of a pot at a depth where theres good root development (yes it will disturb the roots in that area) and combine with a shot glass of water. Mix around well and stick your ph and ec meter into the "Slurry" and se what kind of numbers your getting.

 

[Delps8]

What's your temperature, RH, and wind speed on the plant?

 

[OneHitDone]

What's your temperature, RH, and wind speed on the plant?

I am in a cool location.
Temps generally 75-82 veg and Flower. Veg humidity up into the mid 60's. Flower always below 60 and sometimes dips to just below 50.
Don't have a # for wind speed but the leaves all just have a light flutter to them.

 

[OneHitDone]

When I was running in coco probably the best fertilizer I used at the time was CX Hydroponics COCO A&B
I actually had that mix lab tested. 7.5ml each of A&B in a Gallon of Distilled water yielded these results.
Interesting the lack of Iron. They are clearly putting the iron in one of the supplements you run along with the base.
I believe it was Bio Balancer, Head Masta, Regenaroot if I remember correctly.

 

[Delps8]

I am in a cool location.
Temps generally 75-82 veg and Flower. Veg humidity up into the mid 60's. Flower always below 60 and sometimes dips to just below 50.
Don't have a # for wind speed but the leaves all just have a light flutter to them.

"flutter" - text book

75-82 and 60's - see above. A lot of nutrient imbalances are caused by EC not being adjusted for VPD but I don't think that's the case here since those numbers are so good. Those temps that you're hitting in flower would give me pause. At those temps, transpiration will drop so water uptake and nutrient uptake will drop along with it. Might want to bump EC when things cool off.

The only other temperature-related item that comes to mind is that P uptake is inhibited when the root zone temp drops <64°F.

Sorry I don't have any insights but I think you can strike temp, RH, and wind speed off the list.

 

[OneHitDone]

"flutter" - text book

75-82 and 60's - see above. A lot of nutrient imbalances are caused by EC not being adjusted for VPD but I don't think that's the case here since those numbers are so good. Those temps that you're hitting in flower would give me pause. At those temps, transpiration will drop so water uptake and nutrient uptake will drop along with it. Might want to bump EC when things cool off.

The only other temperature-related item that comes to mind is that P uptake is inhibited when the root zone temp drops <64°F.

Sorry I don't have any insights but I think you can strike temp, RH, and wind speed off the list.

I would investigate EC of media, not nutrient solution

 

[by2]

Exactly - salts just keep twin pushed up in the media making bad zones for the roots.
Have you thought about doing a "Slurry Test" like a lot of organic growers are doing? Take a shot glass or so of your coco out of a pot at a depth where theres good root development (yes it will disturb the roots in that area) and combine with a shot glass of water. Mix around well and stick your ph and ec meter into the "Slurry" and se what kind of numbers your getting.

So I added 0.2g/l epsom salt to the nutrient mix and sprayed them with 2g/l Epsom salt.
The epsom salt added 0.16EC so total EC is 1.345, PH6.0.
I did top feed and checked the run off and its all over the place. I measured all 10 plants and the EC was between 1.5 - 1.9 and PH 5.2.
So decided to water them until plenty or run off and the EC was below 1.4 and PH 5.8

 

[by2]

What's your temperature, RH, and wind speed on the plant?

temp 70-80f, 50-60% humidity. I only have one AC infinity fan above the canopy on low speed.

 

[by2]

I did water all the plants with a sprayer and collected the first water that came out.
I don't think it is an accurate way to check the EC since there is salt build up on the top of the pots that gets flushed down.
The salt build up on the top is harmless since there are no roots growing there.

EC in 1.345 PH6.0
EC out 1.5-1.8 PH 5.2-5.8