HELP! Leaves are yellowing then forming white/grayish splotches

[scrump]

A description of your problem: Lower leaves are yellowing then forming ugly white/grayish splotches
Your Setup: Growing medium is a cross of 50/50 Black Gold AP Potting Soil and Black Gold Natural & Organic Potting Soil. Nutrients are DynaGro Bloom (NPK = 3-12-6) 1/4tsp per gallon (every other watering). Using a 3x3x5 grow tent with Viparspectra 450w LED.
Did you do anything different before the problem occurred? Not that I can think of. Started noticeably after switch to flowering.

If I find any leaves that better show the issue I will do my best to upload them as soon as I can.

Is this a sign of a deficiency or something worse?

[Marley]

Looks like a Nitrogen deficiency. Did you cut back on the nutes recently? 1/4 teaspoon per gallon seems pretty low.

[NebulaHaze]

I agree it looks somewhat like a Nitrogen deficiency, especially since you mentioned they seem to be appearing at the bottom of the plant. If the yellow leaves fall off easily or the plant seems relatively pale or lime green overall that's another sign it may be a Nitrogen deficiency (if most leaves are dark green, or if yellow leaves don't pull off easily, it's usually something besides a Nitrogen deficiency). Since placement on the plant is very significant, is it possible to post a picture of the whole plant in the setup under the grow light?

If it's just 1-2 leaves on an otherwise fern green plant, I wouldn't worry too much because it's natural for the plant to lose at least a few leaves over its lifetime. But if there's several yellow leaves it is a problem this early in the flowering stage. Have you been checking the pH? If it's not lack of nutrients, the #1 most likely trigger for nutrient deficiencies is the pH is too high or too low at the roots.

One thing I've noticed about cannabis plants is they get way more picky about pH and nutrients in the flowering stage than in the vegetative stage!

[scrump]

I agree it looks somewhat like a Nitrogen deficiency, especially since you mentioned they seem to be appearing at the bottom of the plant. If the yellow leaves fall off easily or the plant seems relatively pale or lime green overall that's another sign it may be a Nitrogen deficiency (if most leaves are dark green, or if yellow leaves don't pull off easily, it's usually something besides a Nitrogen deficiency). Since placement on the plant is very significant, is it possible to post a picture of the whole plant in the setup under the grow light?

If it's just 1-2 leaves on an otherwise fern green plant, I wouldn't worry too much because it's natural for the plant to lose at least a few leaves over its lifetime. But if there's several yellow leaves it is a problem this early in the flowering stage. Have you been checking the pH? If it's not lack of nutrients, the #1 most likely trigger for nutrient deficiencies is the pH is too high or too low at the roots.

One thing I've noticed about cannabis plants is they get way more picky about pH and nutrients in the flowering stage than in the vegetative stage!

Here are some shots of my ladies. This plant in the first two pics is yellowing a lot but the splotches are forming on the other plant (last photo). The plant with the splotches has also seemed to have lost the most leaves.

I haven't been checking the soil pH but the watered has always been in a range of 6.3-6.8 (roughly)

I watered today with 1/2tsp of the DynaGro nutrients and 1tsp of GenHydro's CaliMagic

[DewbeeDub]

I agree it looks somewhat like a Nitrogen deficiency, especially since you mentioned they seem to be appearing at the bottom of the plant. If the yellow leaves fall off easily or the plant seems relatively pale or lime green overall that's another sign it may be a Nitrogen deficiency (if most leaves are dark green, or if yellow leaves don't pull off easily, it's usually something besides a Nitrogen deficiency). Since placement on the plant is very significant, is it possible to post a picture of the whole plant in the setup under the grow light?

If it's just 1-2 leaves on an otherwise fern green plant, I wouldn't worry too much because it's natural for the plant to lose at least a few leaves over its lifetime. But if there's several yellow leaves it is a problem this early in the flowering stage. Have you been checking the pH? If it's not lack of nutrients, the #1 most likely trigger for nutrient deficiencies is the pH is too high or too low at the roots.

One thing I've noticed about cannabis plants is they get way more picky about pH and nutrients in the flowering stage than in the vegetative stage!

Remember if your ph is off, the plant will manifest problems, just like yours. The issue will look like a deficiency, but it just can't properly uptake nutes due the ph issue. I had the same thing happen to me 5 wks ago. I ran out of FFOF soil and I had to find a soil quickly to use. I picked up some cheap, but OMRI organic soil at Home Depot. It was supposed to be ph balanced, with lime, but the ph was way off.

After a few days in flower, I started to have the same issues that you are having. I had yellowing and spotting of my fan leafs. They looked almost exactly like yours. Like Nebula said, it started on the bottom/oldest leafs and was working it's way up. I instantly diagnosed it as a nitrogen deficiency. The other plants I had in the FFOF soil where green and beautiful. I decided to do a slurry test on the soil, bc of this. Happened to be that it was a ph issue locking the nitrogen out and appearing to be a nitrogen deficiency. So I flushed, used ph balanced water, gave the plant SLF-100 and slowly, but surely, the plant started to come around. It is now starting to catch up with the plants in the FFOF soil, but undoubtedly these plants will probably suffer on the total harvest weight due to this.

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I've check the pH for both, and I'm getting a reading of 6.4-6.5pH for both of them.

I'm really unsure as to what to do at this point.

[NebulaHaze]

Can you post a picture of your plants in the setup under natural light? How far away are your LEDs? What is the temperature and humidity?

[scrump]

I can't really get pics of the grow area without affecting their current lighting schedule. The lights are about 18"+ above the plants. The pistils are browning slightly. I don't know whether this is due to them maturing or if the burn/deficiency/etc is spreading upwards.

[Sheesh]

How far into flower are you? Tough to tell, but it looks like a few weeks. A few pistils browning early is usually not a problem a few weeks in. What is temp and humidity? Are you measuring your solution ph after adding nutrients? Nutrients typically lower ph substantially. I've had a few issues with yellowing mid to late flower and using Cal Mag every watering and feeding helped a lot. I also add Nitrogen to the P and K flowering nutes every other feeding during flower.

[scrump]

How far into flower are you? Tough to tell, but it looks like a few weeks. A few pistils browning early is usually not a problem a few weeks in. What is temp and humidity? Are you measuring your solution ph after adding nutrients? Nutrients typically lower ph substantially. I've had a few issues with yellowing mid to late flower and using Cal Mag every watering and feeding helped a lot. I also add Nitrogen to the P and K flowering nutes every other feeding during flower.

Temp is around 77-80 (but has peaked to 90% during the warm days we have been getting recently -living in an attic apartment doesn't exactly help with temp fluxes), humidity is 20-30%

I always check the pH after I've added nutes.

Tomorrow it will be exactly 1 month of flowering time.

Strain is Jack Herer and the given flowering time is "8-9 weeks." I'm just worried about making it to then.

[Sheesh]

Low humidity and high temps may show a bit of heat stress but your issue does look like Nitrogen related. How about a flush to make sure salts aren't limiting uptake? Go to 1 tsp per gallon of cal mag (check that on the bottle, I'm going by memory). Bump up your nutes some after the flush, unless you're seeing nute burn on the tips. Boost nitrogen a bit until later in flower. Good luck

[NebulaHaze]

I agree it's too early to see this much yellowing but not an emergency yet. After seeing the pictures in regular light I'm not sure it looks like a nitrogen deficiency to me because the yellow leaves are not wilty. They're yellow but standing straight and don't appear to be falling off on their own, which is a main symptom of a nitrogen deficiency. Additionally the plants themselves don't appear light green, which is usually the other main sign of a nitrogen deficiency.

To me this says you're dealing with some other problem or deficiency. They don't look droopy at all so I don't think it's any kind of watering or root problem.

So to triple check:

• Did anything happen soon before you started seeing problems? For example did you start giving any new supplements, change the water source, foliar spray, have a really cold night, anything like that? When did you start adding CaliMagic? Can you think of anything different or unusual?
• You've been checking the pH of the water going in, as well as the pH of the water going out the bottom? If it's coming out very different that's a sign the pH at the roots might be a factor.
• Is it possible to move your LED grow lights up a few more inches to see if that helps? They're already 18" away which is good for many models, but some plants are very sensitive to higher levels of light and it can't hurt to see if that stops the spreading, but the fact that all the problems are located at the bottom of the plant makes that seem less likely.
• Are all the leaves turning color not getting any light? Is it possible it's only happening to leaves that aren't getting any light?
• What nutrients and supplements are you using for the flowering stage? You mentioned Dyna Gro Bloom, which is great.
• Can you walk us through your watering program? Do you give nutrients every time? Do you get runoff water?

I'm really sorry you're dealing with this! The good news is your buds are fattening up very nicely! They're a very good size for just one month of flowering!

[scrump]

So to triple check:

• Did anything happen soon before you started seeing problems? For example did you start giving any new supplements, change the water source, foliar spray, have a really cold night, anything like that? When did you start adding CaliMagic? Can you think of anything different or unusual?
• You've been checking the pH of the water going in, as well as the pH of the water going out the bottom? If it's coming out very different that's a sign the pH at the roots might be a factor.
• Is it possible to move your LED grow lights up a few more inches to see if that helps? They're already 18" away which is good for many models, but some plants are very sensitive to higher levels of light and it can't hurt to see if that stops the spreading, but the fact that all the problems are located at the bottom of the plant makes that seem less likely.
• Are all the leaves turning color not getting any light? Is it possible it's only happening to leaves that aren't getting any light?
• What nutrients and supplements are you using for the flowering stage? You mentioned Dyna Gro Bloom, which is great.
• Can you walk us through your watering program? Do you give nutrients every time? Do you get runoff water?

I'm really sorry you're dealing with this! The good news is your buds are fattening up very nicely! They're a very good size for just one month of flowering!

1: I was using a 1-1-1 ratio solution from vegetative to the beginning of flowering then I switched to the DynaGro. I was using distilled water for a while then switched to bottled spring water but that was some time ago. I don't use foliar spray. I was getting some cold nights dropping into the mid 60's. CaliMagic was added 4/15.

2: I have not been testing the pH from the run off.

3: I'm honestly running out of room, I'm unsure if I can raise the lights any higher.

4: I believe the lower leaves are still getting light.

5: I'm using DynaGro Bloom. Using as directed (1/4-1/2tsp per gallon ever watering)

6: I use jug spring water add nutrients (and now CaliMagic) then test for pH and adjust to around 6.5-6.8pH. Add 1 whole gallon per plant or until I get 20% runoff. I smooth out the bottom of the planter to remove any excess water then put the plant back into the grow tent.

As for the bud size, that is very good to hear. Your manifold tutorial really helped.

[NebulaHaze]

If possible, next time you water could you try measuring the pH of the runoff? That's the only thing I can think of right now, because honestly it sounds like you've been doing everything right! And your plants do look really great overall

[scrump]

If possible, next time you water could you try measuring the pH of the runoff? That's the only thing I can think of right now, because honestly it sounds like you've been doing everything right! And your plants do look really great overall

I can try and do that but the problem is that I'm using General Hydroponics' pH kit. I'm getting discolored runoff so I'm not sure if I pH it if I will get an accurate reading. Also, in the attached photo are the pistils becoming burnt or are the maturing?

[NebulaHaze]

I'm not quite sure. Is it only happening to the ones directly under the LEDs, or to the buds all over? If it's happening all over it's likely just maturation, but if it's only happening near the lights it might possibly be burn.