Leaf problem

[gamdwtj]

possible phosphate and potassium deficiency do you think 3 1/2 weeks into flowering?

[blink_inc]

lack of light and air circulation sounds right.
looks pretty crowded in there.do you run fans down low?

the rest of the leaves look quite healthy to me.

[hybridlove420]

Hello, all smokers and tokers

light, 400w hps 16-18 inches
temperatures, day 25 c° night 19 c°

18 inches is pretty far for 400w. does it get that hot? cuz i have an unvented 600w that can safely sit at about 14 inches (12 or less will eventually cause stress-13 is my limit), mind you its a large room

but its a nutrient problem if anything. just my 2c

[gamdwtj]

top oscillating circulation fan running flat out just bought another fan to put at the bottom. air intake at bottom air outlet at top as for light im just going to have to bend them around, as for the light i can let it get to 14 inches but when i do it shows signs of heat stress. more pics of how the bottoms looking.

[stinkyattic]

The plants look pretty healthy overall and I've just got a couple questions/suggestions:
-Light penetration to low parts of plant may be insufficient. That would cause sloughing-off of leaves that don't get enough light to be useful to the plant.
-The origin of the coco- Are you certain that it was rinsed? Was it the good stuff, or one of the 'off' brands that carries a lot of residual salt with it? Even sunleaves is said to be a salty one. That's something to check.
-I see you are using a coco specific nute so I assume that it contains something to make up for the habit coco has of scavenging calcium.
The underside view isn't really something I'd be worried about. It looks normal- mostly healthy and green, a couple old yellow leaves, no margin or tip necrosis. Adding ventilation is a good call. If anything, I would suggest you are low on calcium but only slightly. In general those plants look pretty darn good. Consider a good flush before placing them into flower.

[gamdwtj]

Cheers stinkyattic much appreciated info.

It was an off brand of coco, i flushed the shit out of them and they have been in flowering for 3 1/2 weeks. i'll let you no if the fan sorts it out.

Thanks to everyone who had an input :rasta:

[gamdwtj]

possible phosphate and potassium deficiency do you think 4 weeks into flowering?

The fan didn't sort it out does anyone know if it's a nute deficiency ( phosphate + potassium ) ? :rasta:

[stinkyattic]

I don't know, it just really does not strike me as a K or P deficiency.

If you like, go ahead and do a light foliar feeding with a bloom nutrient that contains micros and is mixed MUCH weaker than the bottle recommends. I don't think you should foliar with a grow nute, as you appear to be totally fine on N and don't want to overdo it.

Those drying tips and the slight tip scorch in the pics of the individual leaves really make me think that you've got some type of salting issue there. But it is not severe by any means.

Now is a time to work on prevention of future problems:
With coco, feeding to a slight runoff each time (about 10% is standard) is a good idea. This gives you a constant but slight flushing effect and helps prevent medium salting. Have you tried doing a comparison of the pH/EC going INTO the coco vs the pH and EC coming OUT of the coco? I'd check those numbers. If the 'out' EC number is equal to or higher than the 'in' number, you have cause for concern.

[gamdwtj]

I do the 10 to 20% runoff . i'll get on to check-in ph and ec runoff tomorrow and let you know. here's a few pic of how she going :rasta:

[stinkyattic]

And we have a winner! Those pics tell a good tale...
Your leaf edges are curling up slightly. While the plants are very healthy, you are running a bit warm close to the light. The fan will help a LOT but that is a symptom of mild heat stress often combined with arid conditions. The damaged leaves beneath won't heal, but if the problem has not progressed, you can be reasonably assured that you now have a handle on it.
With that runoff, salting shouldn't be your main problem then. Good.
What is the source of your tap water (well, city, other)?
Those plants look excellent to me. You perfectionists, lol.