Is this overwater or nute burn??

Or something else?

I'm in pro-mix with 25% extra perlite for drainage, top feed/water every other day with 500ppm GH nutes till runoff, 6.2pH. Wouldn't they droop if too wet? And they're never droopy, just yellow and burnt fan leaves, mostly toward the outer leaf/tips, hard to believe it's nutrient burn at only 500ppm? I make sure there's good runoff so they get flushed, can salts really be building up? Shouldn't be a deficiency as nute solution is always fresh. Well, it's something, and if I don't figure it out they won't finish at the rate of leaf loss. Educated opinions MOST welcome! Thanks!

Pretty sure thats nute burn buddy, take it easy and water with plain water and see how they react, nice looking buds by the way too

first off your about to lock out your plants you need min 6.5 and up to 7.0 watering every other day ?????? is wrong you need to water every 4 days and you say you reading 500 ppm on your reader have you subtracted your actual water reading ????? from this ???? if not your feeding i would guess your feeding them like 800 ppm

also depending on how long they bin in them small pots i would transplant them into something a lil larger with fresh pro mix

DrFever said:

first off your about to lock out your plants you need min 6.5 and up to 7.0 watering every other day ?????? is wrong you need to water every 4 days and you say you reading 500 ppm on your reader have you subtracted your actual water reading ????? from this ???? if not your only feeding i would guess your feeding them like 800 ppm

Click to expand...

You confusing man, simply that for the dude

Thats deffo under nute and signs of heat stress..

Hmmm. Well I'm using RO water so the 500ppm is all nutrient. I thought pH 6.0 to 6.5 was standard for peat based mixes? I sure don't want to add nutes if they're burning, or flush if they need nutes. I'm leaning towards burn as they look it, it's just baffling as I've run higher ppm in the past with no burn at all?

Too close to the light, burning the thinest part of the leaf on the upper section of the plant.

They're about 2ft below a cooled HPS, thermometer at the tops of the plants reads around 80deg, max 82 lights on, wouldn't have thought that too hot?

MrGhettoGrower said:

Do you ever run plain water? Every other watering should be just plain ph'ed water and then feed, water, feed, water, feed if you haven't been alternating then this is most likely your problem Maybe a possible salt build up

Click to expand...

I just yesterday flushed with plain water in hopes of that being the cure, but I had not been flushing so far, I was hoping a low enough ppm would be enough, but perhaps not?
I'd been doing hydro for years and just started pro-mix so it's new to me. Never had burn in hydro at much higher ppm, perhaps pro-mix is very different?

poindexterous said:

I just yesterday flushed with plain water in hopes of that being the cure, but I had not been flushing so far, I was hoping a low enough ppm would be enough, but perhaps not?
I'd been doing hydro for years and just started pro-mix so it's new to me. Never had burn in hydro at much higher ppm, perhaps pro-mix is very different?

Click to expand...

I'm growing in rock wool now watering by hand feeding and watering every other time! Dirt is the same way isn't~

I guess nute burn is the most probable of the possibilities. It's just weird as a grower friend who's also in pro-mix top feeds daily with 1000ppm, never flushes at all, and has none of the burn I'm getting? Wish there was a way to test plants and know for sure, alas.

poindexterous said:

They're about 2ft below a cooled HPS, thermometer at the tops of the plants reads around 80deg, max 82 lights on, wouldn't have thought that too hot?

Click to expand...

ok then thats not the prob. Flowering plants with a upper yellowing of the leaves can be K def, if this is the case fix it now or plant can pick up deseases.

your dilemma baffles me...You seem to have a good grasp on what you are doing, especially if you have succesfully harvested plants from hydro. Pro-mix is like MG to me, it works well for vegging plants but come flowering, something in these mediums fry the crap out of MJ!!! I would have said your problem is heat stress in combination with low N, just look at the leaves..their curling upwards...classic heat stress but at 80 degrees? Ever heard of sunburn!? What wattage are your lights? And why are you using such small pots!?!?

calicko said:

your dilemma baffles me...You seem to have a good grasp on what you are doing, especially if you have succesfully harvested plants from hydro. Pro-mix is like MG to me, it works well for vegging plants but come flowering, something in these mediums fry the crap out of MJ!!! I would have said your problem is heat stress in combination with low N, just look at the leaves..their curling upwards...classic heat stress but at 80 degrees? Ever heard of sunburn!? What wattage are your lights? And why are you using such small pots!?!?

Click to expand...

Yeah I'm baffled too! I've been growing for years without ever having any leaf symptoms, but in the last year I've been getting constant leaf issues in all my strains. I switched to pro-mix from hydro in hopes of the change fixing it but still can't shake it. Started to think maybe a virus had infected everything? I'm under HID lights but they are cooled and not especially close to the plants, same light level worked fine in the past. Totally baffling, argh!