I'm desperate don't know the problem

[pwdiesel]

Hello everyone

Looks like a great place to get help.

I’m lost and don’t know what is wrong with my plant. Grandaddy Purple in 3 gal fabric bag, 9 weeks old with 12/12 light schedule just flushed yesterday. Run off was 5.8 ph, 2080 ppm at start of flush 620 ppm after flush with 3 gal tap water 6.4 ph. Leaf looks burnt around main cola. Picture for what’s happening. Any suggestions would be highly welcome.

 

[Phytoplankton]

What are you feeding? The lower leaves look ok, the upper leaves are suffering, which points towards a non-mobile nutrient. Given the look of the damage, I’d say a Calcium deficiency.

 

[zigzagman1960]

What kind of lights? LED? What is the temperature during lights on?

 

[pwdiesel]

What are you feeding? The lower leaves look ok, the upper leaves are suffering, which points towards a non-mobile nutrient. Given the look of the damage, I’d say a Calcium deficiency.

Thanks for responding. Hi fox farm trio big bloom,grow big, tiger boom with their schedule at 9 weeks planted in miracle grow potting soil. yeah calcium deficiency is one of my thoughts.

 

[pwdiesel]

What kind of lights? LED? What is the temperature during lights on?

thanks for the question
vivosun LED grow lights about 16 inches above 76 degrees 60% humidity

 

[Phytoplankton]

Thanks for responding. Hi fox farm trio big bloom,grow big, tiger boom with their schedule at 9 weeks planted in miracle grow potting soil. yeah calcium deficiency is one of my thoughts.

I’d get some FF bush doctor (calmag) and give them a dose, it won’t fix the damaged leaves, but should stop further damage. Best of luck, other than the small issue, your plants look very nice.

 

[pwdiesel]

I’d get some FF bush doctor (calmag) and give them a dose, it won’t fix the damaged leaves, but should stop further damage. Best of luck, other than the small issue, your plants look very nice.

Will do! Thanks

 

[Porky82]

They have been burnt from high nute build up in the medium!! 2000ppm run off is very high!
Just like this plant of mine!

 

[Buds Buddy]

They have been burnt from high nute build up in the medium!! 2000ppm run off is very high!
Just like this plant of mine!

Yours look burnt on the edges from too strong of nutes. But I see no rust spots, which the OP has. Rust spots say it's a Ca def.

 

[Porky82]

Yours look burnt on the edges from too strong of nutes. But I see no rust spots, which the OP has. Rust spots say it's a Ca def.

At his ppm he shouldn't have any deficiencys and his pH is good.
His are a lot lighter than mine which does suggest cal mag deficiency but!
Maybe his pH meter is out?

 

[SmokingWings]

Hi fox farm trio big bloom,grow big, tiger boom with their schedule at 9 weeks planted in miracle grow potting soil. yeah calcium deficiency is one of my thoughts.

I would add Calcium to the schedule as soon as possible. If it is already there then boost the dosage a touch.

The color of the leaves looks a bit off but it might be because of the exposure when taking the pictures or because of the grow lights. It does look like a bit more Potassium will help, especially now that they are well into flowering.

... planted in miracle grow potting soil.

Do you remember the color of the bag? Their potting soil mix is in a yellow bag and their gardening soil mix is in a green bag and they are supposed to be two different mixes.

 

[Buds Buddy]

At his ppm he shouldn't have any deficiencys and his pH is good.
His are a lot lighter than mine which does suggest cal mag deficiency but!
Maybe his pH meter is out?

At his ppm he shouldn't have any deficiencys and his pH is good.
His are a lot lighter than mine which does suggest cal mag deficiency but!
Maybe his pH meter is out?

I'm not sure what's in Miracle Grow soil as it's not designed for growing weed. That's why I think he has a Ca def.
That & the rust spots.
As far as pH.... I use FFOF & don't bother to pH at all anymore. But that soil is designed with a 6.3 pH whereas Miracle Grow may be designed to a different pH. I don't really know off hand. But it does sound like a possibility to me. I figure if he can get FF nutes he should be able to get FF soil which is designed for what we grow.

 

[SmokingWings]

I'm not sure what's in Miracle Grow soil as it's not designed for growing weed.

There is the Miracle Grow Potting Mix and then there is their Garden Soil Mix and if I read the info correctly they are really different from each other. And both of them need the growers to jump in and help after several weeks. What kind of help depends on the mix which is one thing in the yellow bag and something else in the green bag.

As far as pH.... I use FFOF & don't bother to pH at all anymore. But that soil is designed with a 6.3 pH whereas Miracle Grow may be designed to a different pH.

There is that which you mention and then there is that Miracle Gro might not even bother with pH since it will confuse many of the people who buy their products. Scott's Miracle Gro has talked about producing a Cannabis specific soil mix for several years now and when they get around to that then they might do something about being up-front regarding the pH in their soils.

 

[zigzagman1960]

thanks for the question
vivosun LED grow lights about 16 inches above 76 degrees 60% humidity

The temperature in your tent needs to be around 84f with LEDs for proper nutrient uptake. Do a google search on LST (leaf surface temperature) using LEDs.

 

[pwdiesel]

I would add Calcium to the schedule as soon as possible. If it is already there then boost the dosage a touch.

The color of the leaves looks a bit off but it might be because of the exposure when taking the pictures or because of the grow lights. It does look like a bit more Potassium will help, especially now that they are well into flowering.



Do you remember the color of the bag? Their potting soil mix is in a yellow bag and their gardening soil mix is in a green bag and they are supposed to be two different mixes.

MG potting mix in yellow bags, will look at Potassium thanks

 

[SmokingWings]

MG potting mix in yellow bags, will look at Potassium thanks

Yellow bag is their basic potting mix intended for houseplants and the growing of summer flowers in pots for the porch or patio. It tends to run low on available nutrients within weeks for the heavy feeding plants like Cannabis, especially when the plant goes into flower. And I feel it is not fortified with the nutrients the plant needs when flowering, especially Nitrogen and Potassium.

 

[WakkaDerpin]

They have been burnt from high nute build up in the medium!! 2000ppm run off is very high!
Just like this plant of mine!

I agree with the nutrient burn and lockout. Fox farm liquid 3 part are strong nutrients. I use 1/4 the recommended unless mobile nutrient deficient. You should have corrected it with the flush, goodjob. Runoff during flower should be about 1000ppm at ph 6-7

 

[Delps8]

The temperature in your tent needs to be around 84f with LEDs for proper nutrient uptake. Do a google search on LST (leaf surface temperature) using LEDs.

Cannabis grows extremely well over a range of low 70's to low-mid 80's but temperate is only one of many factors. Vapor pressure deficit is the driver of transpiration which is the primary driver of water uptake which, in turn, drives nutrient uptake.

Temperature is part of the equation but there are a handful of things that have to work in synch.

LST is important but not in isolation — it's one of the three factors that are used in determining VPD.

This YT video is well worth a listen and this site has a really good explanation of VPD.