Possibly a Potassium (k) Deficiancy but im not sure

Hi there,

I have 2 plants in veg stage, i think they might have a potassium deficiency but im not sure, about 2 weeks ago they had quite a few spider mites which went unnoticed for a few days until the plants started looking a bit unhealthy, since then the spider mites have been removed but the plants haven't recovered, they have purple stems which have lightly started to go away after a few days but its not completely gone, the leaves are yellowing from the outside towards the center like a Nitrogen and potassium deficiency and are curling down slightly, not a lot, a lot of the young leaves have little yellow tips and the older leaves also have yellowing tips but they also have slight burnt tips, some leaves also have little brown spots, they look like burn marks caused by a potassium deficiency, some older leaves also have rust color blotches like a potassium deficiency. Little leaves have started developing rust colored marks, like a nutrient burn, like its been burnt from the tips but i doubt its over fertilization, how would i know the different though??

It could very well be a potassium deficiency but Ive read that with a potassium deficiency its likely that Phosphorus becomes toxic and the plants need to be flushed. What should i do next? If i just feed more NPK for a N or K deficiency it could make a nutrient burn a toxicity worst but if i flush wouldn't that make the N or K deficiency worst???

Please, can anybody help me??

,
Charl.

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What is your pH at?? Both input water and runoff? Also, disease is a possibility.. Mites can cause infection, as can other things.. Also, have you lifted them out to take a gander at the roots??

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The dudes in dirt man.

I've always found a way to see a root or two atleast in dirt when I've felt it necessary.. Then again, I'm one of those OCD ppl who's willing to sit there for a few hours working out a game plan of sorts, before jumping in and doing more damage than necessary.. Perhaps you're right though, if the person doing it feels uneasy about it, its likely to go bad..

High there,

The Spider mites shouldn't be a problem, i sprayed them 2 weeks ago with bio-grow( containing pyrol) and less than a week ago with the other bio-grow (containing neem oil). I also introduced a preying mantis to eats some eggs and mites. My PH of nutrients im adding is 6.5, i haven't checked the PH of run-off but i will next time i feed. I'm growing in a peat and perlite mix with GHE Flora series nutrients, so its basic hydro. If i move the top layer of peat away, roots are white, to me that means the are healthly or not been eaten by nats. ( i dnt have nats )

So you guys reckon i should flush them and then feed NPK??

There could be a multitude of problems from a nute def to lockout to reaction to the shite you sprayed on them. I would give it a good flush and wait a few days then feed 1/4 - 1/2 strength nutes with Cal-Mag+ added into the mix. Of course PH is a big factor. With that mixture of growing medium, you should be at 5.8ph....not 6.5. Give it a whirl and see what happens

is Cal-Mag+ calcium and magnesium?? How would i add that, im using
the GHE flora series, wouldn't i simply mix a stronger nutrient solution??

What kind of problems could the organic pesticide cause??

The organic pesticides could have caused the leaves to turn color or slightly burn when the lights come on.

Cal-Mag+ is a liquid that you add to your nutrient mixture @ 3ml per 4l or 1 gal. The directions say 5ml per 4l but I cut it down a bit. You would add it to your GHE flora with a syringe.

Thanks man, i just flushed them, ill see what happens. whats the product called though? or is it Epsom salt? Ive heard of Epsom salt helping for a Magnesium deficiency.

Most ppl have sufficient calcium in tap water.. Lime also contributes, and its in alot of nutes too.. Epsom salts costs $2 for a lfetime supply, and it often does help, but I don't think thats what you're facing at all, and adding Ca/Mg can make lockouts way worse if its not called for..
I'm not saying that the mites are still the issue, I'm hoping they didn't infect your plant with a disease..

Ye i don't think its a Mg problem.. What kind of diseases are you referring too? I still its most likely to be a Potassium def but im not sure so I'm hoping the flush i gave them a few hours ago should take care of whatever the problem is if its not a potassium def like a salt build up or toxicity. Would flushing cause any further problems if it was a deficiancy? I just read somewhere that if it is a deficiancy flushing could make it worst if you dont feed right away, Is this true? I flushed with normal
water (ph ± 5.8 )

What kind of soil?? Its not MG soil, or some time release stuff is it??

Its a peat and perlite mix

Know the runoff pH yet?? Peat really acidifies things.. That could explain it wholly since perlite will do very little to buffer that.. Alot of ppl think that perlite is compised of alot of calcium like lime, but its actually a form of volcanic glass, its mainly SiO2 and has very little other beneficial minerals..

I haven't taken the ph of the run-off yet, i flushed them with a lot of water, thought it would be a bit pointless with so much water, im waiting for them to dry out before i feed them with 1/2 or 1/4 strength, ill check the ph of the run-off then.

what should i be expecting after a flush?? ive never flushed my plants before.
Should i expect more yellowing?

My runoff was usually 0.3-0.6 lower than my input water when things were going well.. If your runoff is more acidic than would be healthy for hydroponics at any time, then that is bad, or if you added a ton of water, and it still drops quite a bit, it would likely drop alot more if less diluted and it stayed in contact with the soil longer..
See cannabis actually prefers hydro-like pH regardless of growing medium.. But with hydro we control the pH directly, wheras in soil, there are bacteria, fungii, protozoa etc that accumulate right near the roots (in the rhizosphere) that tend to produce acidic by-products that lower pH.. If we don't neutralize some of those with atleast pH6-7 water things get too acidic, and N, P and K get locked out if the rhizosphere is under ~pH5..
And for the record, an EXCELLENT pH down is water thats had alot of peat soaked in it.. Peat is fairly acidic.. Whenever I use peat pellets I soak them in alot of pH 7.5-8 water for over a day..
Regarding my pH shifts though, the drops I stated were in much more diverse, decently neutrally buffered soil..

High,

Its been a couple of weeks since i last posted about my problem im having, after i flushed my plants, the plants dropped off all those leaves with burns. but they still haven't recovered.. There is still a lot of yellowing and leaves still dropping, im not sure if its a really bad nitrogen(N) def because thats what the yellowing looks like but can be mistaken for a ottasium(K) def too, any advice?

Hope its not a lockout. Id really like them to recover soon so i can flower them, im running out of space and i have a very healthy mother going so i can see how bad the 2 other plants are looking. I feed them with a mild nute solution after i flushed them(they dried first) and now continuing with mother nutes. If anybody has been following this thread, please help.

I did take the pH of my runoff and its about 0.3 lower than my input. Im using a dodgy pH tester, got a colour chart so i cant be to sure im buying a digital tester tomorrow!! so ill have accurate readings soon.

The strain im growing is cheese.

If anybody has questions that might result in a answer, please dont hesitate to ask.

See images below.

Thanks in advance,
Kind Regards,
Charl.