Potassium Deficiency?

[Spackler]

Hi all, I was like 80% sure this is a ph imbalance that's causing potassium deficiency but i would really appreciate a confirmation and also to check that i am taking the right steps in fixing it.
I'm in a 2'x4'x60" tent using a 300w (really 146w) marshydro light that i keep about 20 inches away, temps range from 68-86 with humidity being around 45-60%.
Soil is black gold seedling mix, before this happened water ph was 6-7 with runoff being 4-5ph, using 350 ppms of dyna gro nutes(ruled out nute burn cus of low ppm from my research..).
Once leaves started showing pale spots near the edge i flushed with 6ph water until runoff was 5.5ish (using liquid ph tester), no nutes. Then waited two days for soil to dry up a bit, leaves got worse at the tips so i added 400 ppm nutes. I thought everything seemed fine but now i see a little discoloration on a lower leaf..

 

[jumpincactus]

its possible. could also be under or over water and maybe hungry for N

 

[Spackler]

Nope

thats helpful thanks

 

[jumpincactus]

its possible. could also be under or over water and maybe hungry for N

Hope this was more helpful

 

[jumpincactus]

but to stop playn it just might be lacking potassium. chasing nute deficiencies can be a pain. Sometimes symptoms mimic other issues. Its a process of elimination.

 

[Spackler]

but to stop playn it just might be lacking potassium. chasing nute deficiencies can be a pain. Sometimes symptoms mimic other issues. Its a process of elimination.

Thank you, ya im leaning that way because i weigh the plant on a scale to figure out when to water and get the hang of how it feels so..

 

[Aqua Man]

I dont know much about soil so I'm just going to ask the question. Could it be root bound? And let someone more knowledgable answer it.

 

[Madbud]

I like that you’re weighing the pot, that plant only takes 10-15g water/day. Hows your drainage?

 

[JWM2]

Your runoff is way too low. It’s passing through acidic soil and that’s lowering the runoff ph. You want your soil ph around 6.3-6.8 ideally. That would be my guess. The nute lockout is from being outside the ideal ph range.

 

[JWM2]

I just had a similar issue with some seedlings. I forgot to ph balance the peat pellets and experienced exactly the same thing. Once I realized I skipped a step I supplemented them with dolomite lime to raise the ph and they took off. I was in a rush and paid for it.

I’m switching to rapid rooters from now on so I don’t have that problem again.

I also supplement my soil mix with lime to help with calcium, magnesium and ph. Plants love it. Usually when I get a nute lockout it’s due to ph drifting too low, a dose of lime and they are back in the game.

 

[Spackler]

I like that you’re weighing the pot, that plant only takes 10-15g water/day. Hows your drainage?

Its decent, the soil mix is mostly peat moss with perlite and dolomite, next time i will prob add more perlite. A full water brings it to 11.6 oz so i usually wait till it hits about 6oz to water again since it feels like theres still a bit of water near the bottom and it starts looking droopy at 4.8 ounces.

 

[JWM2]

Hit it with some dolomite lime. Mix some powder up with your water until it’s milky white and water it as you normally would. It should help.

Also with all the flushing I’d insert a probe into the soil and loosen it up some. Watering makes it compact and it’s hard for the roots to breathe.

 

[Spackler]

I just had a similar issue with some seedlings. I forgot to ph balance the peat pellets and experienced exactly the same thing. Once I realized I skipped a step I supplemented them with dolomite lime to raise the ph and they took off. I was in a rush and paid for it.

I’m switching to rapid rooters from now on so I don’t have that problem again.

I also supplement my soil mix with lime to help with calcium, magnesium and ph. Plants love it. Usually when I get a nute lockout it’s due to ph drifting too low, a dose of lime and they are back in the game.

This is what i think is happening also. I was going to transplant into better soil and add some dolomite lime, but i feel this might stress the plant to much. Should i wait to transplant and try to fix it? I feel i cant get the ph right in this soil, the runoff has been low since i first planted

 

[JWM2]

No you’re good. Go ahead and transplant it. Just mix in some extra lime with your soil. Or you can water it with the lime like I stated above and wait a few days and then transplant it. Fresh soil is usually a good thing and won’t stress her anymore than living in acidic soil is already stressing her.

 

[JWM2]

Peat moss is very acidic. And it gets worse as it breaks down. I avoid it completely most of the time. I bought these peat pellets cuz I was in a rush and couldn’t wait for my rubber plugs to show up. Luckily I knew exactly what was going on once they started showing signs of stress.

 

[Spackler]

Thanks everyone! I really appreciate all the help!