Nute burn, potassium or ??

[blondie]

Not sure what issue this is. The soil is fairly new, might be hot nute burn? It does look like lack of potassium to me as well??

I really don’t know what’s up with this grow. Never had anything quite like this before. This plant has been in a small container where I’ve taken care not to over water.

Ive had two different ph meters that wouldn’t calibrate so still unsure my water ph. Been using snow though and ph drops show ph below 7. Doesn’t seem ph could be the issue. I see zero evidence of bugs. I Used a magnifying glass to check under leaves and didn’t see anything resembling frass, larvae... nothing.

 

[Creeperpark]

If you have new soil and you haven't run a lot of water through washing out the potassium, the problem is caused by a pH in the low 5s. In other words too low of a pH. Potassium is available in a pH range between 5.7 and 10 even 11 pH and when it gets locked out it's because of too low of a pH. Now, if you have a stable pH in the 6s range in the root zone then it means it is time to feed a complete fertilizer and give the plant potassium. I use to have a lot of problems with pH meters too. Here's one that has been super for me, it's an Oakton and will hold calibration for a long time. Its very quick too! I hope that helps friend.

 

[Creeperpark]

If one wants to raise the pH of pure water they can add very little tap water to raise it. Store-bought "pH Up" is 30% solution of potassium hydroxide and is the same in tap water. If you added a little tap to the pure water and get the pH to about 6.5 the plant would respond.

 

[HempKat]

I agree with what Creeperpark is saying but since the drops seem to be showing just below 7 for the PH maybe the first thing to try is feeding them a complete grow formula fertilizer I also say that because your newer growth looks a bit lighter green then the bigger, older growth which could be the signs of a nitrogen deficiency beginning. Then if that doesn't seem to have a positive effect try working on raising the PH a little. It also looks like maybe you're being just a little too careful with the amount of water you're giving them, that soil looks pretty dry. If they're not getting enough water that's going to minimize how much nutrients in the soil are getting into the plants. One thing that concerns me though is that one lower, older leaf on the plant in the upper center part of your picture does look like something has attacked it at some point but I don't see the same signs on any of the other leaves or other plants. So maybe if something did attack that leaf whatever it was may have died off since you said you didn't see any pests when you examined them with a magnifying glass.