Brown Spots Into Yellow Leaves, Unable To Remedy And Need Some Guidance

[T0x1x]

Hi all,

I'm a first time grower that is really struggling with an issue on my grow. I think part of it is not knowing what to expect... would love any insight you may be able to offer!

The Problem: Many of my lower/older fan leaves will slowly develop brown spots, which then spread a yellow around the leaf before curling and eventually dropping. I've gone through many different possibilities of what is happening, and nothing has seemingly made a dent. The progression is slow, but steady. I've lost maybe 4-5 leaves over the last couple of weeks - but the plant doesn't have that many to give. Details below, but initially I was watering the plant with tap water for maybe the first 4-5 weeks and everything was great. Cue flowering, and the yellowing beginning - I pH'd my water with GH drops and found it to be above 8.5 (!!). I figured this must have been the issue, did a big flush with neutral pH water and now carefully pH my water + light nutes before putting it in. However, this hasn't remedied the solution. I do have another plant growing in the same conditions (but different strain) right behind it and it seems to be very happy. Oddly, the runoff from the soil (through fabric pots) comes out quite low pH (maybe 5.8ish?) even when I put straight tap water in at 8.0pH. I've heard mixed things about using soil runoff, especially for soils like FFOF, so I'm not sure that's a good signal to follow. I water when the plant is light/dry, erring on the side of underwatering if anything. Really at a loss and hopeful someone can offer some advice! For all I know, this isn't unexpected and things are going OK... the buds still seem to be forming up nicely and the plant isn't really showing much in the way of distress except for the rest of the leaves being a little pale.

The Details:

• Strain: Royal Queen Sherbet Auto (Sativa 35%, Indica 60%, Ruderalis 5%)
• 6 weeks after the sprouts opened the cotyledons. I'd say 2-3 weeks into flowering.
• Indoor Soil Grow - 3 Gallon Fabric Pot (maybe 2 gallons of soil) - Soil is Fox Farm Ocean Forest with maybe 10-15% perlite.
• Light is a Mars Hydro TS1000 - following their guidelines of distance (12") and power at each stage.
• There is a fan for air circulation, as well as an exhaust fan.
• Temp is 70-75F, Humidity between 40-47%
• No signs of pests.
• Watering about every 3-4 days (when pots are light). Only putting in ~0.5 gallons of water, most of the time no runoff.
• Using Fox Farms Trio per their feeding schedule at 50% strength.
• Water pH: First ~4 weeks was 8.0ish, now using ~6.5pH (runoff is slightly lower) - PPM is 148 (tap water)

Pics:

1. Pic of full plant with damaged leaf in view.
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2. Close-up of what it starts to look like initially before progression.
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3. Final form
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4. From a week or so earlier than the previous photos
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[Phytoplankton]

Welcome!, First, they don’t look bad. My best guess is it’s a watering/feeding issue. The plants look very droopy, 2 gallons of FFOF isnt much soil, make sure that the edges of the soil/pot get watered well and the water doesn’t just run through it because it’s too dry. Water to 5-10% runoff, use full strength nutes. Know also , if you don’t already know, that you’re gonna have to do a flush right around flip/stretch to get rid of the built up salts in the FF trio.

 

[T0x1x]

Welcome!, First, they don’t look bad. My best guess is it’s a watering/feeding issue. The plants look very droopy, 2 gallons of FFOF isnt much soil, make sure that the edges of the soil/pot get watered well and the water doesn’t just run through it because it’s too dry. Water to 5-10% runoff, use full strength nutes. Know also , if you don’t already know, that you’re gonna have to do a flush right around flip/stretch to get rid of the built up salts in the FF trio.

Thanks for the reply! I am mostly worried about losing too many leaves at this point and hoping I can get it to power through. I will start watering this guy until runoff and up the nutrients a little bit. Coincidentally, I did a flush right near when flip would have been (it's an auto), so I think I'm going to be sitting good from that perspective. Are you thinking overall it's underwatered?

Do you think pH is an issue at all? I think the flush+input water is all now pH'd correctly, but the runoff is still quite low.

 

[SmokingWings]

Good looking plant and judging by the photos not all that much of a problem.

Watering about every 3-4 days (when pots are light). Only putting in ~0.5 gallons of water, most of the time no runoff.
Using Fox Farms Trio per their feeding schedule at 50% strength.

Are you thinking overall it's underwatered?

I can't speak for @Phytoplankton but yes, it is not getting enough water. When these Cannabis plants enter into flower they start to use even more water than before.

At their peak growth in flower it is not all that unusual to read msgs from other growers who are starting to have to water once every day and half to as often as once a day. And, a proper watering session will be to give enough to get all the soil moist again and not give a certain amount and figure it is enough.

Gotta keep in mind that once the plant starts to flower then it is time to water for the plant plus for all the extra growth that is not leaves. That means all the flowers and buds have to figure in on how much water the plant needs.

Same for fertilizing. Now that the plant is flowering it needs more nutrients to support the extra growth. There is a change in the amounts recommended for the Fox Farms trio once the plants start their flowering stage.

Consider adding Calcium to the feeding schedule if you have not started doing that already.

It will be hard to get rid of the damage that has already started on the leaves but it should be easy to slow it down and reduce the number of leaves that are turning yellow and brown and will fall off.

Do you think pH is an issue at all? I think the flush+input water is all now pH'd correctly, but the runoff is still quite low.

If you have the pH of the input water close to the 6.3 range recommended for soil growing then you should be good. The general feeling is that it is not necessary to fiddle around with the pH of the run-off water. It is the water's pH going in that is important. The run-off pH is used by those who are growing with a hydro style as to way to judge how the plant is reacting to the non-soil environment the roots are growing in.

 

[T0x1x]

Gotta keep in mind that once the plant starts to flower then it is time to water for the plant plus for all the extra growth that is not leaves. That means all the flowers and buds have to figure in on how much water the plant needs.

Same for fertilizing. Now that the plant is flowering it needs more nutrients to support the extra growth. There is a change in the amounts recommended for the Fox Farms trio once the plants start their flowering stage.

Consider adding Calcium to the feeding schedule if you have not started doing that already.

All great points, really appreciate your feedback! I have been adding calcium (Cal-Mag supplement) but again, at 1/2 strength of the recommended dose. I'm guessing this is further exacerbated by the fact that I'm watering less than a half gallon every 3 days, so the doses are quite small all things considered.

Definitely going to up my nutrients and watering schedule on this guy. I also appreciate the pH notes. There are so many hyper-complex resources on pH out there, it can be really intimidating as a beginner to try to balance all of that... run-off pH, input pH, PPM, reading accuracy. Boiling it down to input pH and working off that will probably help me not change so many variables so many times.

 

[SmokingWings]

I have been adding calcium (Cal-Mag supplement) but again, at 1/2 strength of the recommended dose.

It is hard to overdose the Calcium. Yes, it can be done but under normal conditions it is hard. The calcium will do a lot to slow down the problems you are seeing. At 2 to 3 weeks into flowering it will be hard to stop and then reverse the problems but if it slows down and effects fewer leaves then I look at it as the first step towards a win.

I do not grow autoflowers. I can schedule when and which photo-period plants I will be putting into the flowering tent and will start my flowering feed schedule 2 to 3 weeks before that date.

 

[Phytoplankton]

Really not a lot of difference between the care/feeding of photos vs auto's. I'd start with the bloom nutes about week 3-4, since 90% of the time they will be in flower by week 5.

 

[T0x1x]

Thanks all, happy to have some support and guidance!

Lots to learn on the first grow, excited to get better and spread the knowledge

 

[Phytoplankton]

Do you think pH is an issue at all? I think the flush+input water is all now pH'd correctly, but the runoff is still quite low.

PH your input water after the nutes are added, disregard the PH of the runoff. Chasing runoff in soil will lead you down a rabbit hole. FFOF is buffered, as the water sits in contact with the soil the PH will rise. I personally would ph the nutes to about 6.2, but 6.5 will work also.

 

[T0x1x]

Yep - it's kinda surprising how much the nutes drop the pH of my water - it's from a 8.0 to 6.5ish.

One thing I've noticed is that the leaves never really perk up, even after a watering. I'm guessing that has something to do with the nutrient deficiency?

 

[Homegr0wer89]

Yep - it's kinda surprising how much the nutes drop the pH of my water - it's from a 8.0 to 6.5ish.

One thing I've noticed is that the leaves never really perk up, even after a watering. I'm guessing that has something to do with the nutrient deficiency?

How do you water the plant?
You should be getting the top good and wet then flood the top and wait for the water to go down then repeat till run off. This method will pull oxygen down into your plants roots.

 

[Phytoplankton]

Yep - it's kinda surprising how much the nutes drop the pH of my water - it's from a 8.0 to 6.5ish.

One thing I've noticed is that the leaves never really perk up, even after a watering. I'm guessing that has something to do with the nutrient deficiency?

My best guess is it’s a root/watering issue, made worse by lack of nutes. Those are pretty small pots. I have a feeling the edges of the soil are drying out much quicker than the center The center roots are waterlogged/damage/ or oxygen deprived and the edge roots are not thriving either because they’re drying out.which leaves the plant in a nearly permanent droop. Read the primer “proper way to water a potted plant” by @Emilya Green , you”ll learn a lot about making the plant healthier.

 

[T0x1x]

Thanks for the suggestion, that article is super informative! Right now I'm just using a spout-style watering can and trying to distribute as evenly as possible (but never pausing or stopping). I don't know if it's the pot I have (or the soil being very dry) but getting water to the sides is tough because it wants to run down the side of the pot between the dirt and the fabric and then just leaks out.

I'm going to start following this new watering method, for this grow and future grows. I'm guessing I have many of the problems described in this article.

 

[cbdhemp808]

One thing I've noticed is that the leaves never really perk up, even after a watering. I'm guessing that has something to do with the nutrient deficiency?

This could be a sign of a pot drainage problem. Are you getting good runoff when that happens? It could also be a sign of a pathogenic fungus in the roots.

 

[T0x1x]

Hey All - Not sure if it's 'bad form' to post an update on an old-ish post on this forum, but wanted to give a little info on where I'm at.

This could be a sign of a pot drainage problem. Are you getting good runoff when that happens? It could also be a sign of a pathogenic fungus in the roots.

I did start getting some good drainage once I upped my watering amount. Now I can water confidently to ~10% runoff or so.

I have started to follow the full feeding schedule of Fox Farms + Ph'ing the water after adding nutrients to it. I haven't had to do much adjustment after adding nutrients, the pH from nutes alone drops from 8.5+ (my tap water) down into the ~6.5 region. In between the 2 feedings a week, I've been watering maybe once or twice with pH'd plain water.

I think the browning has slowed a bit, but honestly it's hard to tell. Pretty consistently losing 1 or 2 leaves every couple of days. Almost all of them at the bottom of the plant. The leaves are also still pretty pale (pictures don't quite do it justice), but as far as I can tell, the flowers are still packing it on.

Definitely am noticing some brown spots popping up on the sugar leaves (see pics below). The main cola is fine, but many of the smaller ones (seen in the last couple pics) are starting to get them more consistently. I'm guessing I still have 2-3 weeks on the main before it's ready to be chopped, maybe a bit longer on the smaller ones.

Mainly at this point, I'm wondering if I just have to ride this out and hope for the best? I'm not sure if the brown spots I'm seeing on some sugar leaves will hurt the harvest or force me to chop early? Curious what y'all think as well.

Overall Plant:

Main Cola:

Smaller Colas:

 

[Grow AZ]

Hey All - Not sure if it's 'bad form' to post an update on an old-ish post on this forum, but wanted to give a little info on where I'm at.


I did start getting some good drainage once I upped my watering amount. Now I can water confidently to ~10% runoff or so.

I have started to follow the full feeding schedule of Fox Farms + Ph'ing the water after adding nutrients to it. I haven't had to do much adjustment after adding nutrients, the pH from nutes alone drops from 8.5+ (my tap water) down into the ~6.5 region. In between the 2 feedings a week, I've been watering maybe once or twice with pH'd plain water.

I think the browning has slowed a bit, but honestly it's hard to tell. Pretty consistently losing 1 or 2 leaves every couple of days. Almost all of them at the bottom of the plant. The leaves are also still pretty pale (pictures don't quite do it justice), but as far as I can tell, the flowers are still packing it on.

Definitely am noticing some brown spots popping up on the sugar leaves (see pics below). The main cola is fine, but many of the smaller ones (seen in the last couple pics) are starting to get them more consistently. I'm guessing I still have 2-3 weeks on the main before it's ready to be chopped, maybe a bit longer on the smaller ones.

Mainly at this point, I'm wondering if I just have to ride this out and hope for the best? I'm not sure if the brown spots I'm seeing on some sugar leaves will hurt the harvest or force me to chop early? Curious what y'all think as well.

Overall Plant:

Main Cola:

Smaller Colas:

How much flowering time do you have left? From the photos it seems like you’re at the ride it out stage. The plant doesn’t look too bad and you should have a decent first grow. Just use all the notes from above on your next grow and I bet it will be much better. It took me a long time to learn how to water properly (slow and patiently) along with proper nutrient mixing and PH’ing but it sure does make a difference. Be sure you PH your mixture before watering if you have let the mixture sit as the PH will change as it sits. It took me a while to realize that too. Keep up the good grow!

 

[SmokingWings]

Hey All - Not sure if it's 'bad form' to post an update on an old-ish post on this forum, but wanted to give a little info on where I'm at.

Not even an old-ish thread, only been a week.

I did start getting some good drainage once I upped my watering amount. Now I can water confidently ...

Certainly looks like an improvement in the overall appearance of the plant. And the buds are looking really decent.

I have found it very hard to eliminate problems with spots in leaves or leaves starting to turn yellow or brown once the plants have entered into the flowering stage. One thing that makes it hard is that the plant will stop most new root development and will concentrate on flower growth. Basically, the roots that are there when the change starts are what the plant will have the rest of its life cycle. Keep the plant watered so as to not loose any of them to dehydration might be the best we can do about that.

Couple of things. Many symptoms of leaf problems do not go away even if the needed nutrient is added to the schedule or the levels are increased.. The leaf will not improve and any yellowing or the brown spots are there forever. The idea of introducing the missing nutrient or amounts is to prevent the problem from spreading and/or getting worse. We can feel that we are on the right track when the existing leaves and any new leaves do not develop the problem signs.

The other thing is that once stretch part of flowering starts the plant stops growing new large fan leaves. When the stretch ends the only new leaves will be small sugar leaves and the occasional very small 3 finger leaf in the buds.

When beginning the next grow plan on keeping up with a fertilizer schedule with whatever product you prefer and also start the schedule soon after the early seedling stage.

And those brown spots showing up in the yellow leaves....I used to have them and once I started using the recommended dose of calcium, or a tad bit more, the problem has gone away. Most of the time I forget it was ever there on any of my plants. So, no more 1/2 doses of Calcium.

 

[T0x1x]

Thanks all for getting back!

How much flowering time do you have left?

Based on the strain info of harvest in 8-9 weeks (which seems pretty aggressive...) I have only 1-2 weeks left. They had their first real leaves around May 7th (and started bud sites at the very beginning of June) so somewhere in week 7 right now probably.

The idea of introducing the missing nutrient or amounts is to prevent the problem from spreading and/or getting worse. We can feel that we are on the right track when the existing leaves and any new leaves do not develop the problem signs.

That's definitely good advice. I think my only real concern at this point is the brown spots that are developing on newish sugar leaves in the colas. You can see them in the "smaller colas" section of my update. Those weren't there at my original post, but could be just residual response to my underwatering and under-nutrienting initially.

Not sure that it is really hurting anything at this point to be honest, but being new to it, the harvest point (and when to call it early if things are going south) is definitely a little intimidating. Especially when you see folks saying to be careful using trimmings/etc when they are browned.

 

[013]

nice work so far!! ditto damaged leaves do not recover - look for sign of recovery in newer growth.

i believe your soil is almost hydrophobic where it resists water. The wet dry cycle is great for veg to build roots, but now in flower you can water more frequently. I think it might benefit you to bottom soak in an inch ir two of water, then top water too. Let her sit fir a few minutes to bubble and gurgle, then lift the grow bag out of the water so it takes a pee. Set it on a grate like an elevated over rack and let it drip back into the tub or sink

imho- you’ve got a lot more than 1 or 2 weeks to go on those beautiful puff balls. All the fluffy white pistils need to turn colors and crinkle up. Don’t forget you lose a week to 10 days transition time switching from veg to flower…

it’s way too soon to think about flushing too. That plant needs full steam ahead for several more weeks my friend. This is where you throw the kitchen sink at her….

yive done fantastic getting this far own your own, Nope keep posting right here so we can keep tabs on you!!

Welcome aboard!!

edit to add… my bad it’s an auto so no flipping anywho she’s still not close to harvest based on pistil color

 

[cbdhemp808]

Hey @T0x1x, they're lookin' pretty good!

The concept of senescence comes to my mind, and it's something I am tuning into more and more with my own grow.

In biology, senescence is the general concept of "deterioration with age." In cannabis grows, I think of it as a point where the plant is nearing the end of its normal lifecycle, which ends with flowering and producing seeds – except we don't usually grow pollinated plants.

What we ideally want is mature, ripe flowers before a lot of senescence sets in. Senescence will appear as yellowing leaves, dead spots on leaves, dead stigmas (white "hairs" turn brown/orange), and dead bracts (female reproductive parts of the flower). The term for dying plant parts is necrosis. Stigmas are the first to die, and that's normal and to be expected – it helps us determine the arrival of harvest time.

Sometime, when growing conditions are not ideal and the plant is stressed toward the end of its lifecycle, we see what I call premature senescence, meaning yellowing and necrosis are setting in too soon. One side effect is that mold and fungus can take a foothold on dead material. Another side effect is that flowers may be poorly developed, meaning small colas, and low levels of cannabinoids and terpenes.

Problems in the root zone, I think, can bring about premature senescence. It can be caused by a combination of things.

Anyway, perhaps this explains what you're seeing, in which case there's not a lot you can do – as others have said – except continue to fertigate.