please help me diagnose this problem

I have 6 clones vegging (3 White Grapes by Hazeman and 3 Kosher Kush by RP) under 400w mh, they are in 200mm pots (don't know the volume) containing a 70/30 mix of coco and perlite. I water them pretty much as needed, which tends to be once every 2 or 3 days.

They have only been under the 400w for a couple weeks, but the plants are pretty old. I took cuttings before flipping my last grow to flower, and so these cuttings were probably kept in solo cups for a good ten weeks after they rooted.

I am getting black and brown dried out spots on my leaves, and graying dried out leaf tips.

I can't see bugs for the life of me, I saw a few weird bugs on a single leaf about a week ago, they were like really small (a couple mm or so in length) worms/caterpillars which were completely translucent, I have a lot of experience with bugs and cannabis but I could not identify them.

I have since treated with several thorough sprays of insecticidal soap and some root drenches with azadirachtin and have not seen them since, yet the damage persists.

My suspicion is this is bug damage, that is exacerbated by quick onset to mould due to high humidity in my grow room (it is Autumn here and I don't have a dehumidifier).

I should point out, I don't think it is nutrients or Ph, these plants are clones from my last run and are getting the exact same nutrients, maybe not as heavy on the dose but the affected growth tends to be old growth rather than new, so as far as I am aware that rules out nutrient problems.

Any help would be greatly appreciated! This issue is also affecting my mothers and in particular I would HATE to lose my cut of Kosher, that shit is stanky dank and the yield is on point!

P deficiency.

how are you oxygenating your water?

no its not potassium deficiency at all

first off your leaves are sagging and curling so your watering too much, the soil is too cold or your possible off on your ph in that regard..

they look hungry

phil k said:

no its not potassium deficiency at all

Click to expand...

Phil, for fucks sake, P is Phosphorus and K is Potassium. At least learn that before you try to help others fix their problems.

You may be right in that the soil is cold because that will inhibit P uptake but I think that you probably arrived at that answer by accident.

your plants should always be healthy this is a bunch of random genetics in cups but the leaves should always be perky

CC seriously I'm not here to match cock sizes.. its not potassium deficeny your not looking at the whole plant your looking at the damn burn and burn only you idiot

Eager... how do you oxygenate your water and also just to shut CC up put your feeding schedule up and the nutrients your using?

Phil you are an moron. Again P is Phos. and K is Potassium. The signs are a classic example of P def.

BRO SERIOUSLY SHUT UP your giving new people bad advice this is why i always stayed away from boards.. its like the dingdongs only chime in and and give new growers bad advice without knowing anything about their grow.... its ALWAYS HEY YOU HAVE A deficiency!!

Look at the plant .. he's clearly overwatering the plants sitting in wet soil thats why the leaves are sagging.. when they sit in wet soil it generally stays cold. the wet soil chokes the oxygen out and creates the exact same fucking burn that your seeing.. so please don't tell me you know what your saying without looking at the whole situation and knowing exactly how he's going about feeding

now back to helping him and not beating off on the boards....

EAGER:
How do you oxygenate your water?

How many times a week are you feeding nutrients in the water?

also you say you water when they need it. is the soil going bone dry or keeping some moister? when you grow with soil you need that soil to completely dry out in-between waterings... not almost dry but completely i generally tell everyone to do your normal watering then wait for the plant to completely sag before watering again. that way you know your dry out limits on the pot size your using ... the roots need that dry out to seek and spread for food and water..

the browning your getting when your growing in soil can also be caused by soil mites.. they are a bit hard to notice.. they leave no marks on your leaves but they do create that same burn. soil mites are in all soils(eggs) they hatch generally when the soil stays too wet too long and they reside on the top of the soil. most of the time when they get bad you can see them come out of the soil when you water.
have you noticed and small flys? again they wont leave marks on your leaves they feed off the roots and water in the soil

if you notice that your leaves are brittle or feel much dryer than normal i would look for the soil mites.. they are very prevalent in soil grows. and like i said they create the exact same burn issues.

one last thing in regards to your pics.... like i said it can be a few things till you give a bit more info... but in some pictures on back leaves your curling way too much sagging is one thing.. but when your curling and close to the tips lie you are it could be a PH issue also how are you PH balancing your water? sometimes ph too high causes the leave curl and ph too high too long will also create the burn your seeing.

Really appreciate the responses so far! What a great community you have here, people answer your thread straight away!

I am growing in coco and perlite, not soil.

I don't oxygenate my water, I get fresh water every time I water them so there is no need to oxygenate it.

I let the medium dry out between waterings, because I have used azadirchtin twice in the last 6 days the plants have only been fed once in that time.

I am pretty sure I am not overwatering, this is my third grow using coco/perlite and I am watering at the same frequency as normal, if not a bit less. I tend to let my grow medium dry out between waterings, I admit if it has been a few days since they got fed and there is still a touch of moisture I may water them, but coco is pretty forgiving with watering, I have never managed to overwater in coco before and this is my second run with the genetics. The top leaves are not curling or anything like the affected leaves, but I will avoid watering for a few days to make sure.

The grow medium would be very cold now you mention it, my grow tent is in the garage and as I mentioned it is Autumn here. They are in a grow tent, but under the tent is some very thin carpet and then concrete.

I haven't noticed any bugs other than the ones I mentioned and a touch of fungus gnats. This isn't fungus gnat damage, there is minimal fungus gnat presence in my grow medium, if at all, and from experience my couple soil drenches of azadirachtin would have solved the problem easily if it were FG.

Its a P def...hahahahah

looks like burn.

No wait...its mag


um...mb its N


its mites yeah thats it


better check your ph


hey wait a minute...i dont even grow.

why cant peeps just say the truth...i haven't a fricken clue

Shrug

I don't Ph my water, my tap water comes out a touch over 6 and my nutrients bring it down to just under 6. I have used this water and these nutrients on both of these strains before without any issue.

so theres the issues ... i would say the coco isn't drying out i can obviously see that from the saging...thats clear... the burns are coming in from low PH and oxygen in soil or coco you need to be at 6.2-6.8 i generally tell everyone to be at 6.5 in any media grows.. hydro is much different.. your not technically running that..

your coco has a neutral PH so when your dropping it to 6.0 and its drying its rebalancing to 7.0(neutral) that means your plants are swinging a whole point sometimes from dry out to next 6.0 water. ... but you really need to oxygenate your water... basic tap with basic oxygen is fine for babies or clones but not enough for mature plants.. i can't put links up but we've been selling a medical soil program in michigan for years... i know soil grows like the back of my hands i just need more info like you just gave..

So just to be clear
one the sagging is from overwatering
the burns and curls are ph
I would oxygenate the water if you don't want to use a air stone 1ML-5 gallons is low enough to completely oxygenate the water and low enough to not kill beneficial bacteria.