Deficiency or nutrient burn?

I am growing in coco under LED light, and I'm starting my 4th week since the 1w/12 flip. Only a few leaves are exhibiting twisted tips with browning on the leaf serrations. There is also yellow tips, so I think I'm seeing nutrient burn. I was only using 500-600 ppm nutrients (450ppm of base nutrients plus 170ppm of Cal-Mag). I am questioning if I'm misdiagnosing my plants, since potassium deficiencies look similar to me. My pH has been kept around 5.8. I water to runoff every night, so maybe I'm overwatering too. The temps have been high 50-68F at the canopy, and humidity has been 50-60%. This is my first time growing so any advice is appreciated.

This is the overall state if my plants: Here is one of the few trouble spots:
I am not too concerned about this, but I want to learn about it to avoid this mistake in the future. Is it nutrient burn, pottasium deficiency, both, or neither!?

First I would Say they look good but lil behind in formation ...yes nute burn .
I have never grown in coco but maybe a coco guy agree you need lower ph .
Now the temp I would like to see them at 70-80 .
I feel your root zone maybe too cold and could result in certain lock out ..
Not 100 percent but low root temps certain things wont be picked up by your root system (lock Out ).

So you think it is a combination of nutrient burn and a deficiency?

beepy1 said:

So you think it is a combination of nutrient burn and a deficiency?

Click to expand...

It first sign with tip burn . Try get temps up at least to 78 .

If the pots are small enough to move I'd soak them in a slightly weaker solution than you normally feed them with for a minute or two, before allowing to drain.
Even when you feed low concentrations food, coco has a way of accumulating ppms in the bits not touched by roots. I have seen pots have runoff more than double what they were fed with if not flushed like this every 3 weeks or so (We don't have any flushing agents or empty chelates on the market locally)

That's what I ended up doing yesterday. I used 150ppm solution and the runoff was measuring 270ppm. Before this, the runoff ppm's were much lower than what I was pouring in. Since these leaves are burnt, should I cut them off?

Pa-Nature said:

First I would Say they look good but lil behind in formation

Click to expand...

If they are behind in development, will that affect my yeild or bud quality? Or will it just take longer to flower before they are ready? The breeder suggests it has a 9 week flowering time. Also, in your opinion are they just a little behind or a lot?

Depends on strain and lights and many other factors .
Here is a 9 weeker at 5 weeks

beepy1 said:

That's what I ended up doing yesterday. I used 150ppm solution and the runoff was measuring 270ppm. Before this, the runoff ppm's were much lower than what I was pouring in. Since these leaves are burnt, should I cut them off?

Click to expand...

definitely do not cut them off. sounds like you're on track to recovery. Though the plants look really good aside from minor burn, i also agree with pa nature, they look behind. 50-68 is pretty chilly for cannabis. 50s probably slow enzymatic activity in the plant and that could be why you're experiencing the slower bud setting. if you can, as pa suggested, get the temps up, and try not to get below 65 at night.

Continue with your pH value of 5.8...this is correct. As noted by the other members here, your temps are pretty darn low for the lights on period. This is most likely affecting your plants growth habits. At 4 weeks into flower, they should be showing a bit more. Before you do anything else I'd try to get your temps adjusted and if you don't have something between the bottom of your pots and the floor (aside from pot saucer), I would but a 'buffer' between the two to help mitigate cold from coming up through your pot. Your plants look pretty good...maybe just kissed with a bit too much nutrients, but that's really the goal anyhow, so I wouldn't change anything in that respect. If your temps are the issue, once you get that variable squared away, I would imagine you'll see immediate results. Good luck.