Slow growth and leaf problems - autoflowers

PrinsesS

PrinsesS

Active Member
Hi,

I am growing for the first time and I'm running into a problem I can't seem to figure out. My plants' leaves seem to be burning or turning yellow, then brown and brittle starting from the tip and them spreading along the sides of the tip before travelling inward. What's interesting is that each pair of my plants is in a slightly different soil mixture yet they all have the same problem, and I am barely giving any nutes because some of the soil I bought had some in it. In the 30 days that the plants shown below have been growing from seed, they've been given 1 dose of Fox Farms Grow Big and Big Bloom, at a ratio of 1/4 tsp per 2L water. (ph adjusted to 6.0~7.0). I've also flushed the soil once already to try and fix the issue with little to no change. The grow room is a 4x2x5 grow tent with 1200w of mars hydro LED. Temps at canopy height are around 77'F and the lights are 20" above.

One thing to point out is that one bag of soil I bought came with a bunch of fungus gnats which I've been treating using BTK, hydrogen peroxide (8:1 water:h2o2), and yellow stickies, but I still manage to see a few here and there running around, never really flying (maybe because of the fans).

Out of pure desperation the other day I mixed a watering of grow big and like 1/16th of a tsp, literally a teeny pinch of Cha Ching so that together I'd get a nice Nitrogen kick, and I noticed that the sick plants seemed to perk up within the following hour. They looked like they were totally jacked and liked whatever they were getting, so I know they need something, but I'm afraid of over fertilizing if the problem is nute burn.

Any thoughts?

Also, do the larger plants in the pics look right for an autoflower at 30 days? There's not a pistil in sight, and the seedbank I got the seeds from is being evasive instead of helpful.

20151203_181820_resized.jpg 20151203_181847_resized.jpg 20151203_181912_resized.jpg 20151203_182105_resized.jpg 20151203_175803.jpg
 
PrinsesS said:
Hi,

I am growing for the first time and I'm running into a problem I can't seem to figure out. My plants' leaves seem to be burning or turning yellow, then brown and brittle starting from the tip and them spreading along the sides of the tip before travelling inward. What's interesting is that each pair of my plants is in a slightly different soil mixture yet they all have the same problem, and I am barely giving any nutes because some of the soil I bought had some in it. In the 30 days that the plants shown below have been growing from seed, they've been given 1 dose of Fox Farms Grow Big and Big Bloom, at a ratio of 1/4 tsp per 2L water. (ph adjusted to 6.0~7.0). I've also flushed the soil once already to try and fix the issue with little to no change. The grow room is a 4x2x5 grow tent with 1200w of mars hydro LED. Temps at canopy height are around 77'F and the lights are 20" above.

One thing to point out is that one bag of soil I bought came with a bunch of fungus gnats which I've been treating using BTK, hydrogen peroxide (8:1 water:h2o2), and yellow stickies, but I still manage to see a few here and there running around, never really flying (maybe because of the fans).

Out of pure desperation the other day I mixed a watering of grow big and like 1/16th of a tsp, literally a teeny pinch of Cha Ching so that together I'd get a nice Nitrogen kick, and I noticed that the sick plants seemed to perk up within the following hour. They looked like they were totally jacked and liked whatever they were getting, so I know they need something, but I'm afraid of over fertilizing if the problem is nute burn.

Any thoughts?

Also, do the larger plants in the pics look right for an autoflower at 30 days? There's not a pistil in sight, and the seedbank I got the seeds from is being evasive instead of helpful.

View attachment 3556652 View attachment 3556653 View attachment 3556654 View attachment 3556655 View attachment 3556656
Click to expand...
Get some calmag, epson salt, and molasses add these 3 to half gallon of water each one at half of a spoon, repeat this for 2 weeks every time soil dries up, you will be ok. GL
 
Thanks for the tip. I happen to have everything except the epson salt. What makes you think the plants need these 3 things?

Also, the plants might look a bit overwatered because they were watered yesterday evening and the soil still looks a bit damp. The leaves aren't drooping so I don't think they're overwatered.
 
I don't see mg def. I think it's been overwatered at some point. Do you let them dry out? I let mine get very dry, just short of drooping leaves. I lift the containers to sense the moisture content.

The plants look recessed in the container. You may be getting heat trapped in there? It seems like that could be problematic. Do you use an air circulation fan?

If they were all bottom leaves I would say they are light starved. But, you're running 75-80w/sq ft. (That's a lot, even for MarsHydro. They're not the most efficient LEDs. But, 40 in veg, 55 in flower should be good.). So, I can't see how that's it. (A leaf or two don't seem to be shaded either.).

Regarding fungus gnats, if the containers were properly sized to the amount of soil used, you could use posterboard to cover the tops of the containers. I cut circles out of white posterboard, with about 2" overhang. Then a slot from the outer edge to the center to slide past the slot. I make two of those so the slots are opposite each other. (The white posterboard even reflects a little light from the bottom.). That leaves you with the drain holes. I've heard of people using pantyhose to cover the bottom of the container. I use EcoSmart (something) from Home Depot. It's a peppermint/rosemary spray which irritates gnats. I spray around the base of the container after each watering. That's good enough for me.
 
When did the lower/older leaves turn brown? I'm thinking it's root rot-appearing damage from the fungus gnats (before you started treating it.).
 
PrinsesS said:
Thanks for the tip. I happen to have everything except the epson salt. What makes you think the plants need these 3 things?

Also, the plants might look a bit overwatered because they were watered yesterday evening and the soil still looks a bit damp. The leaves aren't drooping so I don't think they're overwatered.
Click to expand...
Get the epson salt, anyways it won't. Hurt your plants in anyways, all 3 i use and never run into this problems, they are all for prevention, before it actually happens. Nutrient Problems with Pictures - Cannaversity http://www.cannaversity.com/cannaversity/article.php?id=057. Look at this and u will see a picture of your plants, im just trying to tell you what it always work for me and even if is not it it will STILL benefit your plants for the micros, sulfur, magnesium,aminos and a lot of other good stuff. Remember what doesn't kill u make u stronger, look any ways at this picture of my clones, they where left abandoned for 9 days while i was in vacation in Florida, they where healthy when i left, when i came back they where eating themselves, so i treated them with epson salt, calmag, molasses and 1/8 of veg nuts and in 5 days they are getting green again. Look also at ma 1 week and a half flowering plant i just mix 18 spoons of epson salt and 18 spoons of dolomite lime straight in ma soil mix, and every other watering i add molasses and calmag and im good, im not talking just for talking i try it all i used to run into shit like that in the past but not anymore. Anyways like i say they are not nuts, they won't hurt, they just help. GL anyways!!
 

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tropicalcannabispatient said:
every other watering i add molasses and calmag
Click to expand...

With epsom salt and gypsum, you shouldn't need calmag in soil. The problem I had using it is that it acidifies the nutrient mix, (requiring more ph up, adding more salts to the soil, leading to acidic soil, leading to the need for higher ph, more phup, etc.).

I start with 150ppm water (tap and RO water mixed together). I don't even ph my nutrients anymore. (But, I do have 1.5 Tbsp/gal dolomite in the soil.). If I have a Ca or Mg def, I treat it with individual components (calcium acetate or gypsum for calcium; epsom salt for magnesium). They produce:

Calcium acetate: 60ppm/gal Ca
Gypsum: 61ppm/gal Ca + 49ppm S
Epsom: 26ppm/gal Mg + 34ppm S​

I use Calcium acetate with epsom salt because gypsum's sulfur might be too much combined with epsom's sulfur.

Calmag is more convenient to use. But, people should consider that it's not required and may contribute to the spiral I mentioned. I would try tap water alone and see how it works (but, dilute as necessary with RO water for a sane 150ppm starting point).
 
az2000 said:
With epsom salt and gypsum, you shouldn't need calmag in soil. The problem I had using it is that it acidifies the nutrient mix, (requiring more ph up, adding more salts to the soil, leading to acidic soil, leading to the need for higher ph, more phup, etc.).

I start with 150ppm water (tap and RO water mixed together). I don't even ph my nutrients anymore. (But, I do have 1.5 Tbsp/gal dolomite in the soil.). If I have a Ca or Mg def, I treat it with individual components (calcium acetate or gypsum for calcium; epsom salt for magnesium). They produce:

Calcium acetate: 60ppm/gal Ca
Gypsum: 61ppm/gal Ca + 49ppm S
Epsom: 26ppm/gal Mg + 34ppm S​

I use Calcium acetate with epsom salt because gypsum's sulfur might be too much combined with epsom's sulfur.

Calmag is more convenient to use. But, people should consider that it's not required and may contribute to the spiral I mentioned. I would try tap water alone and see how it works (but, dilute as necessary with RO water for a sane 150ppm starting point).
Click to expand...
Thats why i have 18 spoons on dolomite lime if it gets acidic. I use one spoon of each per gallon of soil
 
az2000 said:
With epsom salt and gypsum, you shouldn't need calmag in soil. The problem I had using it is that it acidifies the nutrient mix, (requiring more ph up, adding more salts to the soil, leading to acidic soil, leading to the need for higher ph, more phup, etc.).

I start with 150ppm water (tap and RO water mixed together). I don't even ph my nutrients anymore. (But, I do have 1.5 Tbsp/gal dolomite in the soil.). If I have a Ca or Mg def, I treat it with individual components (calcium acetate or gypsum for calcium; epsom salt for magnesium). They produce:

Calcium acetate: 60ppm/gal Ca
Gypsum: 61ppm/gal Ca + 49ppm S
Epsom: 26ppm/gal Mg + 34ppm S​

I use Calcium acetate with epsom salt because gypsum's sulfur might be too much combined with epsom's sulfur.

Calmag is more convenient to use. But, people should consider that it's not required and may contribute to the spiral I mentioned. I would try tap water alone and see how it works (but, dilute as necessary with RO water for a sane 150ppm starting point).
Click to expand...
I dont even ph anything
 
az2000 said:
With epsom salt and gypsum, you shouldn't need calmag in soil. The problem I had using it is that it acidifies the nutrient mix, (requiring more ph up, adding more salts to the soil, leading to acidic soil, leading to the need for higher ph, more phup, etc.).

I start with 150ppm water (tap and RO water mixed together). I don't even ph my nutrients anymore. (But, I do have 1.5 Tbsp/gal dolomite in the soil.). If I have a Ca or Mg def, I treat it with individual components (calcium acetate or gypsum for calcium; epsom salt for magnesium). They produce:

Calcium acetate: 60ppm/gal Ca
Gypsum: 61ppm/gal Ca + 49ppm S
Epsom: 26ppm/gal Mg + 34ppm S​

I use Calcium acetate with epsom salt because gypsum's sulfur might be too much combined with epsom's sulfur.

Calmag is more convenient to use. But, people should consider that it's not required and may contribute to the spiral I mentioned. I would try tap water alone and see how it works (but, dilute as necessary with RO water for a sane 150ppm starting point).
Click to expand...
We kind of do the same but just in different ways and amounts
 
orbo said:
IME molasses is great for feeding the micro herd ... Lots of folks push for it, I don't because IMO it just puts more shit in the soil that probably shouldn't be there.
Click to expand...

I can't think of anything molasses puts in the soil that shouldn't be there. But, fertilizer is a less expensive source of the minerals in molasses. Ordinary sugar is a less expensive way to promote the soil microbes. (Some people use honey. It seems to be a personal preference about being natural.).

I read that it can be overdone and create a hypertonic condition where water is removed from the plant.

I use a small amount. 1/8th tsp/gal each feeding (after 2nd set of fan leaves). Just a little to help "ferment" the soil. It's really to offset the damage done to the microbes by the synthetic nutrients. The more organic nutrients I use, the less sugar I would use. (For example, I use AK Fish emulsion occasionally. That's gooey goodness for the microbes. No reason to add sugar.).

Sugar also attracts fungus gnats. (I wouldn't do it unless I had the container covered the way I mentioned above.).
 
az2000 said:
I can't think of anything molasses puts in the soil that shouldn't be there. But, fertilizer is a less expensive source of the minerals in molasses. Ordinary sugar is a less expensive way to promote the soil microbes. (Some people use honey. It seems to be a personal preference about being natural.).

I read that it can be overdone and create a hypertonic condition where water is removed from the plant.

I use a small amount. 1/8th tsp/gal each feeding (after 2nd set of fan leaves). Just a little to help "ferment" the soil. It's really to offset the damage done to the microbes by the synthetic nutrients. The more organic nutrients I use, the less sugar I would use. (For example, I use AK Fish emulsion occasionally. That's gooey goodness for the microbes. No reason to add sugar.).

Sugar also attracts fungus gnats. (I wouldn't do it unless I had the container covered the way I mentioned above.).
Click to expand...

Excellent points. and +Rep for style..:cool:

Trusting what is stated to be in the bottle vs. was is actually in the bottle compared to its value proposition = unnecessary risk IMO. It's one of those hot buttons here. I say to each his/her own and if you think you see improvement with it, then likely you ARE.

I still think the OP's pH pen needs calibrated. bongsmilie
 
Wow, I didn't expect this kind of response to my issue, I really appreciate it :)

I took some additional pictures today to get another look at some of the problem plants. I wanted to show that even a new seedling, in a COMPLETELY different brand of soil with no added ferts is also experiencing the same (or similar) problem, but this one is, as well as others, are looking dry and yellowish green with some lighter colored splotching. The larger ones all pretty much started out like this and ended up losing their first 2 sets of leaves after they turned brown and crispy. This really disappointed me when I noticed this. I figured the first strain I tried to grow might just be troublesome, so I rolled the dice with 3 new ones, but it looks like they'll suffer the same fate by the way things are progressing.
The only things in common between them all would be that they share the same environment, they're watered with the same tap water (ph 7.0, lucky me), and I assume they're all infested with fungus gnats by now.


az2000 said:
I don't see mg def. I think it's been overwatered at some point. Do you let them dry out? I let mine get very dry, just short of drooping leaves. I lift the containers to sense the moisture content.
Click to expand...

I was letting the plants dry out almost bone dry in an attempt to kill the gnats, but every time I watered I'd see a dozen or so of them start rising to the surface crawling around in a frenzy. It was just recently I saturated the soil a bit during the last watering thinking maybe I was hurting their growth.

az2000 said:
The plants look recessed in the container. You may be getting heat trapped in there? It seems like that could be problematic. Do you use an air circulation fan?
Click to expand...

That was my fault. I misjudged how much soil I'd need, and then when I added water the first time, everything compacted on me and I didn't have any soil leftover to top up with. As for fans, I've got 2 going across the top of the canopy just under the led lights. Having two 600w LED lights in a small tent however has its challenges with heat so the best I can get at times is 77'F at canopy level, but it'll typically hover in the 80's never exceeding 84/85'F. I'd run the exhaust faster but I am trying to keep the noise down; it's loud enough as it is being in my bedroom :)

tropicalcannabispatient said:
Get the epsom salt, anyways it won't. Hurt your plants in anyways, all 3 i use and never run into this problems, they are all for prevention, before it actually happens. Nutrient Problems with Pictures - Cannaversity http://www.cannaversity.com/cannaversity/article.php?id=057. Look at this and u will see a picture of your plants, im just trying to tell you what it always work for me and even if is not it it will STILL benefit your plants for the micros, sulfur, magnesium,aminos and a lot of other good stuff. Remember what doesn't kill u make u stronger, look any ways at this picture of my clones, they where left abandoned for 9 days while i was in vacation in Florida, they where healthy when i left, when i came back they where eating themselves, so i treated them with epsom salt, calmag, molasses and 1/8 of veg nuts and in 5 days they are getting green again. Look also at ma 1 week and a half flowering plant i just mix 18 spoons of epson salt and 18 spoons of dolomite lime straight in ma soil mix, and every other watering i add molasses and calmag and im good, im not talking just for talking i try it all i used to run into shit like that in the past but not anymore. Anyways like i say they are not nuts, they won't hurt, they just help. GL anyways!!
Click to expand...

Thanks, I'll give it a shot with one of them and report back if there's any improvement. If I were to relate my plants to the ones shown in the link above, I would say that they most resemble the Calcium, Iron, and Over-Fertilized pictures combined.

Pics:

(please note that I misted the seedling in an attempt to see the color differences better which is why it looks wet)

20151204_171004_resized.jpg 20151204_171026_resized.jpg 20151204_171359_resized.jpg 20151204_171417_resized.jpg 20151204_171459_resized.jpg 20151204_171517_resized.jpg
 
Last edited:
PrinsesS said:
It was just recently I saturated the soil a bit during the last watering thinking maybe I was hurting their growth.
Click to expand...
They should go through complete wet dry cycles. (I can't tell from your comment if you've been doing daily watering.). You should feed with at least 20% runoff. This will help avoid salt buildup which typically presents as acid soil and nute lockout in early flower. Then let it dry until the container feels very light (but, not to the point the leaves droop. It's not terrible if they do. But, better not to.).

If you do that kind of full watering and then let it dry, I'd like to know how long it takes between waterings. I would add 30% perlite to that soil because it looks heavy to me. My experience has been that *a lot* of perlite is good.

I use 60% Pro-Mix HP, 20% Kellogg Patio Plus (potting mix) and 20% Perlite. The Pro-Mix already has 30-40% perlite. So, my stuff is up there close to 40-50%.

What soil are you using? I assumed it's Fox Farms (which one?).

84 seems high inside the soil. That's starting to push it, I think. I'm in a hot climate and in the summer my plants struggle at the 84-86 range. I've never measured the temperature in the soil. But, I don't see how it would be hotter than the ambient air unless there's some kind of activity happening in there.

What is the PPMs of your tap water? (You can buy a $20 TDS/PPM meter on Amazon. I use the HM EZ-TDS.). If it's too high that could be causing a problem, loading up the soil with non-nutritious stuff, competing with the nutrients. I had that problem when I started. My water's PPM is 600-800. I mix it with RO filtered water to get a starting point of 150ppm.

Chlorine could be a concern using 100% tap. There's not a lot in tap water compared to the unsanitary nature of soil. Soil should win every time. But, I would put a pinch of sugar in the water the night before just to promote some bacterial action and exhaust the sanitizer. Then mix your nutes. (Let it sit too long and it will get gunky.).

If you're in the US you can search for your water provider's required "annual water quality report." That will tell you some things.
 
PrinsesS said:
Wow, I didn't expect this kind of response to my issue, I really appreciate it :)

I took some additional pictures today to get another look at some of the problem plants. I wanted to show that even a new seedling, in a COMPLETELY different brand of soil with no added ferts is also experiencing the same (or similar) problem, but this one is, as well as others, are looking dry and yellowish green with some lighter colored splotching. The larger ones all pretty much started out like this and ended up losing their first 2 sets of leaves after they turned brown and crispy. This really disappointed me when I noticed this. I figured the first strain I tried to grow might just be troublesome, so I rolled the dice with 3 new ones, but it looks like they'll suffer the same fate by the way things are progressing.
The only things in common between them all would be that they share the same environment, they're watered with the same tap water (ph 7.0, lucky me), and I assume they're all infested with fungus gnats by now.




I was letting the plants dry out almost bond dry in an attempt to kill the gnats, but every time I watered I'd see a dozen or so of them start rising to the surface crawling around in a frenzy. It was just recently I saturated the soil a bit during the last watering thinking maybe I was hurting their growth.



That was my fault. I misjudged how much soil I'd need, and then when I added water the first time, everything compacted on me and I didn't have any soil leftover to top up with. As for fans, I've got 2 going across the top of the canopy just under the led lights. Having two 600w LED lights in a small tent however has its challenges with heat so the best I can get at times is 77'F at canopy level, but it'll typically hover in the 80's never exceeding 84/85'F. I'd run the exhaust faster but I am trying to keep the noise down; it's loud enough as it is being in my bedroom :)



Thanks, I'll give it a shot with one of them and report back if there's any improvement. If I were to relate my plants to the ones shown in the link above, I would say that they most resemble the Calcium, Iron, and Over-Fertilized pictures combined.

Pics:

(please note that I misted the seedling in an attempt to see the color differences better which is why it looks wet)

View attachment 3557473 View attachment 3557476 View attachment 3557477 View attachment 3557478 View attachment 3557479 View attachment 3557480
Click to expand...
Mg lockout calcium, iron, and zink, plus ur heat issue, and infestation of gnats, maybe they are eating your roots, maybe is root rot, maybe its too hot in there. Maybe its a bad combo of all of the above. GL
 
Last edited:
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