Potassium DEf. or toxicity. Need some help

Well to start it off i'm growing in coco, with a ph of 6.0 to 6.2 with a run off of 5.6-5.8...Im at day 30 of flowering, this became a problem around a wk ago. already flushed the plants with ph adjusted water to try and leach them out. I was feeding them lucas formula 8/16 with a little cal mag and kool bloom and flplus... Strain is snow cap that is showing the worst signs, and sadly is spreading to a couple others. also hand watering every 24-48hrs

The weird thing is, I have other starins that are growing and are perfectly healthy.. I just am not understanding the problem for some reason and need the help of some fellow growers!!!

onto the problem!!!!
All new growth is turning yellow, with reddish stems and some browning happening on the leaf margins..All under growth of fans leaves seems to be browning and dying off. Ive grown in coco before and nvr had this happen. This is pretty much driving me and my partner fu***ng MAD!!! The buds on the plants are not as phat as others, but there are a couple that are still a nice size..But u can defiantly see a little lacking on bud growth..

Sry i have no pics seemed to misplace my damn camera battery. Our nighttime temps drop sometime over 15deg. or close to 20 sadly..I hate that this happens, but im working with my friends ghetto ass setup. I read somewhere that low temps make the plant have a harder time absorbing potassium!!!


There has been no sign of nute burn, also to let u know.. We have a horrible problem with gnats and spider mites we cant seem to kill...We sprayed floramite and the fuckers are still alive and kicking..Now spraying with neem oil every other day and trying to stop these bitches..are these mites sucking the life out of my babies??? plz help me out

how good is your ventilation? humidity?

the bugs can do crazy stuff to the plant's root also, causing the problems you observe.

I also think you guys are feeding too much stuff.

good luck!

Are you using tap water or RO? If tap, for sure drop the cal-mag. b.360 may have a point about the nutes. 8/16 in coco can lead to a bit of nute buildup. Check h3ad's sticky in the coco forum for reasons to maybe drop to 6/9.

course if you had nute buildup seems we'd be seeing low pH symptoms like Mg def. that low runoff could be from washing out builtup nutes.

New growth turning yellow says something different. Are the veins staying green? course these are high pH problems and again you say your pH is muy bueno. So maybe we're looking at an antagonism between nutrients. Too much of one thing can restrict others.
Iron, which shows on top leaves can be reduced by too much P or by too much Mn. You could get too much Mn from nute buildup and pH in your coco dropping.

Doesn't really matter, all that really matters is that you (now that you've flushed) is to keep a good pH. And maybe reduce your nutes. read that thread.

I agree, this could be the result of bad tap water on your plants. The problem you describe sounds to me to be a magnesium/potassium chemistry related issue. The fact that your coco runs off lower than what you add to it is intriguing as I find coco to buffer the pH up, not down.

Leads me to think salt build up in those plants, while the other plants haven't reacted they still might.

It could be a bunch of stuff though... Could just be that those plants need less nutrients than the other plants... genetics...

bombadil.360 said:

how good is your ventilation? humidity?

the bugs can do crazy stuff to the plant's root also, causing the problems you observe.

I also think you guys are feeding too much stuff.

good luck!

Click to expand...

The Ventilation is fine, and humidity is around 55% to 60..Were adding another Dehumey, in a couple days.

Yeah we are switching to 6/9 instead of 8/16..Thanks for your help man

hazy said:

Are you using tap water or RO? If tap, for sure drop the cal-mag. b.360 may have a point about the nutes. 8/16 in coco can lead to a bit of nute buildup. Check h3ad's sticky in the coco forum for reasons to maybe drop to 6/9.

course if you had nute buildup seems we'd be seeing low pH symptoms like Mg def. that low runoff could be from washing out builtup nutes.

New growth turning yellow says something different. Are the veins staying green? course these are high pH problems and again you say your pH is muy bueno. So maybe we're looking at an antagonism between nutrients. Too much of one thing can restrict others.
Iron, which shows on top leaves can be reduced by too much P or by too much Mn. You could get too much Mn from nute buildup and pH in your coco dropping.

Doesn't really matter, all that really matters is that you (now that you've flushed) is to keep a good pH. And maybe reduce your nutes. read that thread.

Click to expand...

Were using complete R.O water as of now..A wk ago we were using some tap water, so that might have a thing to do with it. Were dropping our formula to 6/9 so we will see if that helps the problem..I hope so