SOIL Potassium deficiency?

[buds73]

Hi all, I spotted what i think could be a potassium deficiency on one of my plants but I'm not sure. I've had yellowing on some leaves that has by all accounts just been natural yellowing due to flowering but this looks different. I gave my plants a dose of bloom nutes on there last feeding at a quarter strength, the first for around 3-4wks as i discovered that my soil had nutrients in it at what ratio i don't know and can't find out that info. My soil is also more alkaline than is ideal and so i have been watering at a PH of 6.2-6.3 in order to try and maintain the PH of the soil. I don't water to runoff and so i don't know what the PH out is. Bloom nutes i used are Bio-Bizz bloom N-P-K is 2-7-4. Pics below any confirmation/advice would be appreciated. Thanks

[growell]

what week flower u in are they doing that then whole leaf go yellow and it mostly affecting bigger leaves i asking cause mine sort doing that look similar 50 days in flower mine also is it in diffrent parts of plant mate

[buds73]

I'm on day 36 of flowering.I had/have yellowing on lower leaves of all my plants but the yellowing was more gradual and blended out from the tips towards the base of the leaf where it still had green on the leaf this yellowing has a more defined edge to it.

[Farmbuck]

How far are you in flowering ? Looks like it just the bottom leaves only so I wouldn't worry too much...

[buds73]

I'm on day 37 now. Think I probably got 3-4 wks left.

[Farmbuck]

Ok ! Just make sure it doesn't go upward. When I'm in that situation and half way of flowering I feed them with a little bit of CalMag but not much but that's me. She may be need a tiny bit of nitro. But beside this they look fine.

[growell]

u could be right try giving nutes every feed u said soil has nutes they should be nearly spent if used since veg and pottasium first one to show just a thought mate

[buds73]

Yeah i was thinking nutes in soil should be spent It's been about 8 wks since i transplanted them they had 4 weeks in the same soil type before transplant. I've held off adding nutes as i was still showing small signs of nute burn but that seems to have gone over last couple weeks which is why i gave bloom nutes another go but the issue has come on since then.

[growell]

if its only affected couple bottom leaves take them off see if it reappears have u changed anything did u spill nutes on them when watering just throwing things out there

[buds73]

Only thing I changed was adding bloom nutes. No spillage.

[CaptainWiese91]

But if you fed them nutes. They should have enough potassium. Maybe you have a lockout ? Because you don’t water to runoff and have some salt buildup in the pot ?

[buds73]

I only gave quarter strength nutes so is possible it wasn't enough. I could have a lock out but I'm not seeing any other signs of deficiency and plant looks healthy otherwise. The leaves don't seem to have gotten any worse as far as I can see. They are due a water today so I'll get a better look when I take them out to water. I'll check my soil Ph at the same time see if that has changed as I've not checked it for a week.

[CaptainWiese91]

It looks like a potassium deficiency for me too,
Just wondering when you fed nutes, but a 1/4 a strength is not much. If the PH is fine, I would treat it as a deficiency

[buds73]

Farmbuck, CaptainWiese91 I add calmag every watering at half strength. Nutes I've used sparingly throughout the grow and may be a little guilty of being over cautious in that respect. I had nute burn early on during veg on top of finding out my soil has nutes in it when i started flowering made me lay off any nutes other than calmag for the first few wks of flowering. I did a little reading on a Bio-bizz site and it recommends on there to use it's nutes every feed/watering rather than every other watering that way the plant doesn't have to adjust each time. Not sure how much of a difference it makes though. I took plants out for a feed earlier. There are no new signs of yellowing edges on any other leaves. I gave them a dose of calmag at half strength and a dose of Grow and Bloom at a quarter strength today and I'm going to keep an eye on it and see how they react over next couple days. I'm wondering if the yellowing that started early in flower was a sign that my plants needed more and i missed it by being over cautious with nutes coupled with the fact I'm a newbie.
With regards to nutrients in soil, is there a way of knowing if one particular nutrient is depleted. Maybe i'm over thinking things but is it possible for soil to be depleted of one nutrient and have too much of another in which case would show nute burn regardless of nutrient dosage given?
Hope this makes sense and apologies if i rambled a bit. I was given the infomation that a friend of mine had passed as i started writing this post and threw me off track a bit.

[SoOrbudgal]

Hey buds it's OK we've all done it more than once.

[CaptainWiese91]

I’m my opinion yes you can lack some nutrients in the soil while still others are available and present.
Which might have happened for you. This is why I use a PK fertilizer, without any N in. With the soil I’m using I know it will run out of P and K before the N.

[buds73]

Thanks @SoOrbudgal
Hmm i thought that might be possible CaptainWiese91 Going to pay more attention to soil on the next grow. Thinking of using Bio bizz Pro or all mix on the next but still undecided as yet.
P.s Sorry for the late replies didn't realise it had been so long since i last logged in.