Yellowing leaves

[Komitose]

I have recently started growing indoors in a 4x4x8 tent. I have 2x800watt lights and a fan for air circulation. Lights are about 2’ above plants. I have grow big fertilizer that I’ve used a couple times — only after leaves started turning yellow. They are in organic potting mix/soil. Temp stays around 65-80 inside tent.
Please help me figure out why they are all dying even though there is new growth .

 

[The Phantom]

Welcome! Take a look at this Thread for help Cannabis Plant and Pest Problem Solver: Pictorial

 

[Sancheh]

I would guess there hungry!!u haven't stated how old they are??maybe add some epsom salts to ur feeding schedule...I'm no expert hopefully they will answer to ur problem

 

[FelipeBlu]

Without any additional information, I would say that they are starving for nutrients. How much Grow Big have you given?

 

[Komitose]

Without any additional information, I would say that they are starving for nutrients. How much Grow Big have you given?

I’ve used about a half gallon of water between all 9 plants with 3 teaspoons of grow big, in the last 7 days I believe.

 

[Komitose]

Welcome! Take a look at this Thread for help Cannabis Plant and Pest Problem Solver: Pictorial

Excellent info. Thank you

 

[StoneOtter]

Hi Komitose, I'm not familiar with your soil. If it's not buffered you'll need to ph the feed and water. Do you know if it is?

 

[MochaBud]

Welcome to the forum @Komitose Nice screen name

^^^^Yep I agree with @stoneotter looks like a PH problem, possibly mixed with spider mites take a magnifying glass and look at the bottoms of your leaves, they will look microscopic spiders and will leave little hairs/webs near the nodes

 

[Komitose]

Hi Komitose, I'm not familiar with your soil. If it's not buffered you'll need to ph the feed and water. Do you know if it is?

What is buffered? I do think you are right though. My soil and ph have to be off. But my house plants are planted in the same soil mixture and they aren’t yellow at all. I used Espoma organic all natural potting mix and then added extra organic worm castings to the top inch of the pot. I just purchased a soil ph test kit today from amazon so hopefully that will help.

 

[Komitose]

Welcome to the forum @Komitose Nice screen name

^^^^Yep I agree with @stoneotter looks like a PH problem, possibly mixed with spider mites take a magnifying glass and look at the bottoms of your leaves, they will look microscopic spiders and will leave little hairs/webs near the nodes

I do see tiny little webs all over the underside !!! How do I get rid of those ?!

 

[Sancheh]

Welcome to the forum @Komitose Nice screen name

^^^^Yep I agree with @stoneotter looks like a PH problem, possibly mixed with spider mites take a magnifying glass and look at the bottoms of your leaves, they will look microscopic spiders and will leave little hairs/webs near the nodes

Man that is impressive !!

 

[FelipeBlu]

I’ve used about a half gallon of water between all 9 plants with 3 teaspoons of grow big, in the last 7 days I believe.

Okay, not hungry if you mixed 3tsp Grow Big mixed into 1/2 gallon of water (30ml/gal). That provides:

455ppm N
131ppm P
252ppm K

This concentration would burn my plants up! Try 9ml/gal (slightly under 1tsp per 1/2 gallon). This provides:

137ppm N
39 ppm P
76ppm K

It’s a little low on K, but if you can find some liquid kelp, like Down To Earth KelPlex, 2ml (slightly under 1/2 tsp) per 1/2 gallon will bring the K up to 164ppm.

Better check your pH too!

 

[Komitose]

I have recently started growing indoors in a 4x4x8 tent. I have 2x800watt lights and a fan for air circulation. Lights are about 2’ above plants. I have grow big fertilizer that I’ve used a couple times — only after leaves started turning yellow. They are in organic potting mix/soil. Temp stays around 65-80 inside tent.
Please help me figure out why they are all dying even though there is new growth .

 

[Komitose]

Okay, not hungry if you mixed 3tsp Grow Big mixed into 1/2 gallon of water (30ml/gal). That provides:

455ppm N
131ppm P
252ppm K

This concentration would burn my plants up! Try 9ml/gal (slightly under 1tsp per 1/2 gallon). This provides:

137ppm N
39 ppm P
76ppm K

It’s a little low on K, but if you can find some liquid kelp, like Down To Earth KelPlex, 2ml (slightly under 1/2 tsp) per 1/2 gallon will bring the K up to 164ppm.

Better check your pH too!

Awesome. I will try this for sure. Thank you.

 

[MochaBud]

What is buffered? I do think you are right though. My soil and ph have to be off. But my house plants are planted in the same soil mixture and they aren’t yellow at all. I used Espoma organic all natural potting mix and then added extra organic worm castings to the top inch of the pot. I just purchased a soil ph test kit today from amazon so hopefully that will help.

In the soil I'm using, Fox Farms Ocean Forest (FFOF) it has ingredients to buffer PH between 6.3 and 6.8...usually Epsom Salts and Dolomite Lime (Garden Lime) depending on acidic levels

I do see tiny little webs all over the underside !!! How do I get rid of those ?!

 

[FelipeBlu]

But first, the mites! I don’t know if you feel like you have too much invested in these plants, but I for one would not want to start having to deal with mites this early into a grow. I would ditch these plants, clean and sanitize thoroughly, and avoid mixing outdoor soil, tools, self, clothes, etc. with anything from outside, which is where the mites came from.

 

[MochaBud]

Last time I got mites, they came in my soil and most problems do stem from not doing preventative maintenance when sprouting or cloning, whether growing outside or in

I now pre-treat all soil with Nemotodes and use the left overs outside

And...when I put "ANYTHING" into soil, I water thoroughly and let drain, then I spray the top of the soil and the underside of the leaves with the "Garden Safe"...this is easier to do when you start in solo cups


And if going outside, I recommend Neem Extract, to add to your water routine, water once a week (w/neem) while vegging...I add 1 tablespoon per gallon neem and 1 teaspoon dawn dish soap...the dish soap is to let oil mix with water and will not hurt your plants....not just any Neem though it has to be unrefined

 

[MochaBud]

Man that is impressive !!

Thank you sir, we're all here to help...oh, and eat popcorn

 

[StoneOtter]

What is buffered? I do think you are right though. My soil and ph have to be off. But my house plants are planted in the same soil mixture and they aren’t yellow at all. I used Espoma organic all natural potting mix and then added extra organic worm castings to the top inch of the pot. I just purchased a soil ph test kit today from amazon so hopefully that will help.

We use a ph pen and test the water and the nute mix before feeding. I use one like the one on the left when I ph. It's around 35 or 40 dollars.

If you ph the water/nutes. Cannabis can only take nutrition when it is available to them at certain ph's. The chart shows what is available for lunch in the ph zone.

So in soil ph 6.5 is central to the zone of availability between 6.0 and 6.8. I've grown a few at 6.5 and they loved it. There's products called ph up and ph down. They get added to correct the situation.

 

[Komitose]

Enormous amount of info to take in. Thank you everyone for the help.