Help Figuring Out Spots On Leaves

[tokm]

These ladies are White Widow, 1 month into flower under 600w HPS in FFOF. My feed schedule is water water feed with GH Flora Series. I PH tap water to 6.3 after letting it sit out for 48 hours.

Some leaves are yellowing and have rust-ish looking spots on them. I have used a 500x digital magnifier on them and there are no critters. I did have to re-calibrate my PH pen a week ago, it was .46 on the high side. I'm not sure if this was from the higher PH or something else. I have fed 2 times with water since re-calibrating my PH pen.

I have also rubbed the leaves with my hands and the rust-ish spots do not come off so it isn't rust fungus. Temps are ~78 and rH is 40%.

 

[tokm]

anyone?

 

[GroJo!]

It looks like a calcium or magnesium deficiency. http://www.growweedeasy.com/magnesium-deficiency-cannabis or http://www.growweedeasy.com/calcium-deficiency-cannabis

 

[tiger mt.]

They look pretty good to me. Maybe the ph was a bit off or you cut nitrogen too early in flower, but I wouldn't worry too much as it appears you are going to crop out fine. Dying or fading leaves during flower isn't too concerning. As the poster above said, could be a cal mag issue, I always think it a good idea using a calmag specific supplement.

 

[tokm]

They look pretty good to me. Maybe the ph was a bit off or you cut nitrogen too early in flower, but I wouldn't worry too much as it appears you are going to crop out fine. Dying or fading leaves during flower isn't too concerning. As the poster above said, could be a cal mag issue, I always think it a good idea using a calmag specific supplement.

I've been feeding CalMag+ in every other feeding. I didn't think it looked like the pix w/CalMag deficiencies. It's spreading fast which is why i am worried.

 

[Bear420]

It don't look like Cal/mag I think your right on that one, to me it looks like now Potassium appears as a firing or browning of the leaf often accompanied by brown spots on the leaf, A tiny bit of Potassium Sulfate will quickly solve the Problem, But over fertilizing or salt stress can often display the same symptoms, So when in doubt flush it out. then mix up a fresh solution.
Like most nuets balance is the key, to much potassium can cause toxicity and that can show up as a Magnesium deficiency too causing interveinal yellowing and will spread further up the plant as it worsens, So if symptoms of Mag appear simply back off the extra potassium and the leaves should green up.but I think your also right on that no being the mag. Good luck I sure hope you get it figured out. they look like there going to turn out great so far, keep up the good work......

 

[tokm]

It don't look like Cal/mag I think your right on that one, to me it looks like now Potassium appears as a firing or browning of the leaf often accompanied by brown spots on the leaf, A tiny bit of Potassium Sulfate will quickly solve the Problem, But over fertilizing or salt stress can often display the same symptoms, So when in doubt flush it out. then mix up a fresh solution.
Like most nuets balance is the key, to much potassium can cause toxicity and that can show up as a Magnesium deficiency too causing interveinal yellowing and will spread further up the plant as it worsens, So if symptoms of Mag appear simply back off the extra potassium and the leaves should green up.but I think your also right on that no being the mag. Good luck I sure hope you get it figured out. they look like there going to turn out great so far, keep up the good work......

thank you!

I def have not over-nuted them, I'm trying to be very aware of that. The most bloom formula I give them is 2 tsp/gal (GH says to give 3 at this point). I just have to get them through one more month. I think I'll flush, then give just bloom in the next feeding and see if it stops. Thanks again, great advice & explanation.

 

[Bangaman]

I should have taken before and after pics. The plant in the picture looked like yours 2 days ago, leaves we bright yellow and 2/3 rd covered in those rust spots. Out of desparation,(It was really bad, all "dead" leaves) I applied Miracle grow all purpose plant food , NPK 24-8-16, 1 Tbl spoon per gallon. THE PLANT PERKED, spots are vanishing. my temp and rh are spot on with yours. My pH is high 5

 

[tokm]

I should have taken before and after pics. The plant in the picture looked like yours 2 days ago, leaves we bright yellow and 2/3 rd covered in those rust spots. I applied Miracle grow all purpose plant food , NPK 24-8-16, 1 Tbl spoon per gallon. THE PLANT PERKED, spots are vanishing. my temp and rh are spot on with yours. My pH is high 5

Thanks, I'm hoping its a Potassium deficiency and the bloom will fix it. If that doesn't work maybe i'll give a little extra nitrogen after the flush. It's started to get up near the bud sites too.

 

[Bangaman]

Its been a while since I last heard someone flush. If you feed as directed there should be no need to "flush". even if you over feed you cannot "flush" the nutes out of the plant. plants do not transpire nutes nor do they piss ntes. Nothing but anecdotes to support flushing, and it makes n scientific sense in the same false logic as a need for "dark time" during veg. Just putting it out there

 

[tokm]

Its been a while since I last heard someone flush. If you feed as directed there should be no need to "flush". even if you over feed you cannot "flush" the nutes out of the plant. plants do not transpire nutes nor do they piss ntes. Nothing but anecdotes to support flushing, and it makes n scientific sense in the same false logic as a need for "dark time" during veg. Just putting it out there

I'm flushing the excess nutes out of the soil, not out of the plant.

 

[Bangaman]

So, you are leaching the soil. It is still impractical and 6nhealthy for the plant all together. The plant still needs the nutes from veg stage just not in the same ratios. So moving forward with a new nute regimen is just as good and very beneficial rather than an attempt to "scrub clean" soil" by leaching. big no no. if you want to start fresh each stage use sand or cocoa beans or coconut husks. Soil is the best natural buffer and therefore extremely forgiving. and leached soil is no good, really

 

[Dr. Who]

So, you are leaching the soil. It is still impractical and 6nhealthy for the plant all together. The plant still needs the nutes from veg stage just not in the same ratios. So moving forward with a new nute regimen is just as good and very beneficial rather than an attempt to "scrub clean" soil" by leaching. big no no. if you want to start fresh each stage use sand or cocoa beans or coconut husks. Soil is the best natural buffer and therefore extremely forgiving. and leached soil is no good, really

Please tell us why?

 

[Dr. Who]

These ladies are White Widow, 1 month into flower under 600w HPS in FFOF. My feed schedule is water water feed with GH Flora Series. I PH tap water to 6.3 after letting it sit out for 48 hours.

Some leaves are yellowing and have rust-ish looking spots on them. I have used a 500x digital magnifier on them and there are no critters. I did have to re-calibrate my PH pen a week ago, it was .46 on the high side. I'm not sure if this was from the higher PH or something else. I have fed 2 times with water since re-calibrating my PH pen.

I have also rubbed the leaves with my hands and the rust-ish spots do not come off so it isn't rust fungus. Temps are ~78 and rH is 40%.

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Your pH is staying too low and it's reducing the availability of particular nutrients.......I would, if I were you. pH to 6.7 for a bit (week) and add a Ca/Mg to your feed.....Then pH to 6.5 and NO lower for soil! I would also DO what G&H say EXCEPT for when to start the "bloom"....Please keep feeding the veg for at least 2 weeks before changing to bloom nutes after you change the lighting time.....

I might suggest a Kelp extract in your feed and to add 1/2 cup dolomite lime to a bag of FFOF soil and mix it in well b4 using it! OF is light on Ca/Mg right out of the bag.

How often do you feed? It is hungry looking across the board.

I would NEVER use MG feeds to "correct" a problem!

 

[Bangaman]

Please tell us why?

The thing with leaching soil is that as you know, onset of flowering not only starts long before you switch to 12/12(maybe a week, maybe more depends on strain or hybrid when the plant hits "puberty") and progresses into full fledged flowering through a few more stages during 12/12. Please correct me if I am wrong)

To keep it short, each phase has different nute needs and the closer u are to the next phase, the more you still need nutes from the previous phase.

In other words although the demands for each pse are different, they are gradual. Leaching the soil sort of "throws the infant in the river" expecting it to swim.

This is my understanding of the flowering preparation physiology. Obviously leaching soil has never killed a plant, but does not optimize the process either. I start the nute switch gradually, but who knows? I have too much time on my hands because mixing nutes can create havoc on PH so you must test it for different ratios. The good news is that soil is an excellent buffer so PH spikes are or can be lower

Please do give me your input.

 

[Bangaman]

The thing about Miracle grow all purpose plant food , NPK 24-8-16 is that although it is an excellent source of primary macronutrients, probably one of the best, and the best bang for the buck ,

It is not a cure-all especially especially if PH is your culprit then nute absorption is out of whack anyways. But, when uncertain as is the case with many follar symptoms, even the most obvious, I apply the rule of troubleshooting-simple least expensive and less invasive fixes first.

1. Proper PH to make sure nutes can be absorbed IF THAT IS NOT IT
   
2. The primary macronutrients: nitrogen (N), phosphorus (P), potassium (K) from a quick delivery source at a regular dose, Miracle grow all purpose plant food , NPK 24-8-16 IF THAT IS NOT IT
   
3. The three secondary macronutrients: calcium (Ca), sulfur (S), magnesium (Mg) IF THAT IS NOT IT
   
4. The micronutrients/trace minerals: boron (B), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo), nickel (Ni)

But because a boost in NPK as primary macronutrients can help the plant correct the #2 and #3 and #4, if the pH is good, I almost never go beyond it

 

[Bangaman]

Quick addition to my last post, my grow medium is a mixture of soil and peat moss. Most secondary macronutrients, and micronutrients/trace minerals are abundant in good soil so this process may not apply if you do not use soil, you use poor soil, reuse your soil too often, or if you "flush," leach your soil a few times

 

[Dr. Who]

The thing with leaching soil is that as you know, onset of flowering not only starts long before you switch to 12/12(maybe a week, maybe more depends on strain or hybrid when the plant hits "puberty") and progresses into full fledged flowering through a few more stages during 12/12. Please correct me if I am wrong)

To keep it short, each phase has different nute needs and the closer u are to the next phase, the more you still need nutes from the previous phase.

In other words although the demands for each pse are different, they are gradual. Leaching the soil sort of "throws the infant in the river" expecting it to swim.

This is my understanding of the flowering preparation physiology. Obviously leaching soil has never killed a plant, but does not optimize the process either. I start the nute switch gradually, but who knows? I have too much time on my hands because mixing nutes can create havoc on PH so you must test it for different ratios. The good news is that soil is an excellent buffer so PH spikes are or can be lower

Please do give me your input.

Mmm, OK.

Interesting

I like that view

Ph havoc - now where talking when it comes to soils!

Soils are only "excellent" at buffering pH if they contain the "right stuff"......Built soils "organic" are best for that. The bio heard in the soil goes farther then MANY think in maintaining pH...

MG has a penchant for disrupting soil pH, not to mention the "bio heard" in the soil. Flushing or leeching the soil with multiple times the pot size in water will only create an overwatered conditition that swings the pH too low for too long - this can aggravate the condition your attempting to fix.

I like to tell people to not "flush or leech" and to simply water the problem away with simply using straight pH'ed water for 7 - 10 days. Sometimes a Ca/Mg should be used with the "water it out" to help stabilize the pH.....

 

[Dr. Who]

The thing about Miracle grow all purpose plant food , NPK 24-8-16 is that although it is an excellent source of primary macronutrients, probably one of the best, and the best bang for the buck ,

This simply makes my head spin! I most assuredly,,,DISAGREE!

 

[Bangaman]

It is

This simply makes my head spin! I most assuredly,,,DISAGREE!

Great! That my preference in product you say it "simply makes my head spin! I most assuredly,,,DISAGREE" Awesome! Now do share why