Need help identifying this leaf issue

Hi All,

I have a grow with 4 auto flowers, 2 purple Hindu Kush, 2 green crack. 2 of them (one of each strain) were ahead of the other 2 by about 8-10”. I’m gonna try to figure that out at some point. They are in 3gal fabric pots with miracle grow potting soil. I have had pretty good luck with this setup when I am there checking on them every day but now I have been trying to do everything remotely and I usually only get to go there about once a week. Not optimal since I kind of suck at identifying problems to begin with and by the time I notice I am behind the 8ball. I have an automatic waterer and they get water every 3 days.

My daytime temps are 75F and I am on 18/6 light schedule. A week ago which is around the beginning of week 5, starting the second week of pre-flower, I lowered the humidity from 65% to 60%. They started to stretch a little more than an inch a day. A couple of days ago I noticed some brown leaves on the webcam so I checked on them last night and took some pictures. I am using well water and reducing the ph of the water to 6.8-7. I usually give a splash of this or that with regards to nutrients when I am there, which is weekly. The last one was a small amount of the following with ph adjusted water: kelp extract, fulvic acid and potassium nitrate. I try to keep from having a heavy hand with them.

Thanks for your help!

Well, I'd drop the PH of your nute solution to about 6.2 (are you using nutes or relying on the Miracle Grow?). Watering every three days is your schedule, but it may not be the plants schedule. From the picture, it appears to be a non-mobile nutrient that's either defiient or toxic, since it's at the top not the bottom. My guess would be Ca or a fluctuating PH level. The biggest issue is with Miracle Grow soil, is it's pre-aended, and time release, so you never really know what nutes are being released at what time.

they look hungy mate, if they are in veg ph the water to about 6.8, if in flower start of flower 6.8ph 3rd week 6.5ph 4th week 6.2ph what nutes are you using?

Phytoplankton said:

Well, I'd drop the PH of your nute solution to about 6.2 (are you using nutes or relying on the Miracle Grow?). Watering every three days is your schedule, but it may not be the plants schedule. From the picture, it appears to be a non-mobile nutrient that's either defiient or toxic, since it's at the top not the bottom. My guess would be Ca or a fluctuating PH level. The biggest issue is with Miracle Grow soil, is it's pre-aended, and time release, so you never really know what nutes are being released at what time.

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I forgot to mention I also usually mix in a small amount of bone meal in the bottom layer of soil, but maybe I wasn’t consistent, I can’t remember. I’m not a huge fan of miracle grow but it is available at the local big box. I sometimes get happy frog too. I had thought about Ca but I had a hard time matching the sample pics. Appreciate your help.

growmaster/plantkiller said:

they look hungy mate, if they are in veg ph the water to about 6.8, if in flower start of flower 6.8ph 3rd week 6.5ph 4th week 6.2ph what nutes are you using?

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I will double check my ph this weekend. I have been using bat guano, kelp and potassium nitrate thus far. My plan was to taper off of the potassium and start introducing some bloom nutrients, fox farm ones like big bloom.

hhl63 said:

I will double check my ph this weekend. I have been using bat guano, kelp and potassium nitrate thus far. My plan was to taper off of the potassium and start introducing some bloom nutrients, fox farm ones like big bloom.

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Big bloom is kinda weak, it’s 0-.5-.7, but it has good stuff in it, if you’re going FF, Tiger bloom should also be used. It’s actually a trio, Grow Big, Big Bloom, Tiger Bloom.

it might not be ph mate as i said to me they just look hungry.

try these steps plants are very quick to respond once the issue is resolved

1 - check the ph of the soil anywhere between 6.2 - 6.8 is ok

2 - make sure you are mixing nutes correctly if you are not feeding then get some, if u are working in soil look at getting something like hesi if you have not been feeding then start low and work your way up

3 - somethings to always have in stock - dolomite lime will keep a soil ph of 7 but you will be fighting it to come down

Molasses - will feed the micro bacteria helping to break down any salts in the soil good comeback aid if you overfeed plus as a standard feed for the soil your plants will love it. 3 tablespoons in 20L water plus use warm water to mix i only use this stuff 2 times in a grow once at the start and then again when they start to flower but it's important to remember this is not a plant feed its just for the soil so when mixing mix your nutes its a normal amount of nutes as stated on the label

deep green leaves = overfeed is heading your way so back off the nutes
nice light green = everything is cool and you can start playing
light green like yours = hungry

watch from the bottom up bro just like any women peace

growmaster/plantkiller said:

it might not be ph mate as i said to me they just look hungry.

try these steps plants are very quick to respond once the issue is resolved

1 - check the ph of the soil anywhere between 6.2 - 6.8 is ok

2 - make sure you are mixing nutes correctly if your not feeding then get some if in soil look at getting something like hesi if you have not been feeding then start low and work your way up

3 - somethings to always have in stock - dolomite lime will keep a soil ph of 7 but you will be fight it to come down

Molasses - will feed the micro bacteria helping to breakdown any salts in the soil good comeback aid if you overfeed plus as a standard feed for the soil your plants will love it. 3 tablespoons in 20L water plus use warm water to mix i only use this stuff 2 times in a grow once at the start and then again when they start to flower but its important to remember this is not a plant feed its just for the soil so when mixing mix your nutes its a normal amount of nutes as stated on the lable

deep green leaves = overfeed is heading your way so back off the nutes
nice light green = everything is cool and you can start playing
light green like yours = hungry

watch from the bottom up bro just like any women peace

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I did not know molasses would do that, cool! I have gotten a little heavy handed with the nutes before, so it looks like I have been overcompensating (under compensating?) lol.

hhl63 said:

I did not know molasses would do that, cool! I have gotten a little heavy handed with the nutes before, so it looks like I have been overcompensating (under compensating?) lol.

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yeah it's cheap too - https://www.amazon.co.uk/dp/B07GVC797L?ref=ppx_yo2ov_dt_b_product_details&th=1&psc=1

makes sure if you do get some its the unsulphured kind

one last thing go easy on your watering cycle wait until the soil is springy before watering if unsure pick up the pots as yours are also showing signs of overwatering as well, google leaves curling downwards and it will explain

That yellowing of the top leaves could be Sulphur deficiency and I reckon I see some signs of Mg deficiency aswell.
Double check you are feeding these

growmaster/plantkiller said:

one last thing go easy on your watering cycle wait until the soil is springy before watering if unsure pick up the pots as yours are also showing signs of overwatering as well, google leaves curling downwards and it will explain

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I can see that too. My last grow I was watering daily and didn’t get enough water down to the bottom for the roots and so maybe some more over compensation Definitely dialing that back too. Well, I am definitely learning a lot tho, thank you very much!

cage said:

That yellowing of the top leaves could be Sulphur deficiency and I reckon I see some signs of Mg deficiency aswell.
Double check you are feeding these

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I usually give them some epsom but haven’t done that yet. Will add some next feeding. As long as I don’t overdo it.

75F ? Are you growing plants or trying to make ice cubes ?

Raise temps to 82-85F, your RH is good.
You have necrosis, which is happening due to toxicity in most cases.
I think you gave too much nutes and also not in the right qtys..
Or you have a build up of salts which also make your soil not good.
I think a flush with 6.3 ph water and 0.5 ec for sometime can reverse this problem if it hasn't been too traumatic for the roots until now.

DanKiller said:

75F ? Are you growing plants or trying to make ice cubes ?

Raise temps to 82-85F, your RH is good.
You have necrosis, which is happening due to toxicity in most cases.
I think you gave too much nutes and also not in the right qtys..
Or you have a build up of salts which also make your soil not good.
I think a flush with 6.3 ph water and 0.5 ec for sometime can reverse this problem if it hasn't been too traumatic for the roots until now.

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Haha yes I needed some for my cocktail . I am now trying to adjust my conditions to be closer to the external conditions to try to save some money. Since I have to pay for heat and humidity, in the winter time I am growing at lower temps. Unfortunately the humidity is a bit high for 75F so I have been gradually lowering it to give me the vpd needed for the lower temperatures. It’s kind of strange that only 1 plant is dealing with this stress as I am trying to treat them the same, more or less, and that worked out well for the last crop. The 2 plants that were stunted in development compared to the other 2 are closer to the humidifier and when I dropped the humidity 5% that plant had a tremendous growth spurt and that’s when I noticed the leaf issue. I am going to go back this weekend and make sure the soil had a chance to dry out and start adding a little bit of bloom nutes and stop with the potassium nitrate (the only salt I use, aside from the minimal amount of ammonium nitrate in the miracle grow). Also a bit of epsom salt may help.

I really appreciate your feedback, cheers!

Some strains are just different
The conditions in which all thrive needs to be normal, it's not good to ponder why one plant can't coup with extreme conditions and others can, first make the conditions solid and normal, which is temp and rh, I'm sure the other plants will still be normal and the one struggling will bounce back.
Next make sure you give water, although weed is a forgiving plant, when you push it indoor at high light hours it will demand more attention and water.

Until now I'm still not sure if we're seeing a toxicity or root rot.. my bet is more toxicity