I diagnosed it wrong..Any ideas?

Coco+perlite, Canna A+B+cal mag, 3 gallon fabric pots, 500w quantum board, 3x6 closet
12/12 lights
starting 8'th week of flower, photo period kandy kush
average RH 55%, daytime 77 Fahrenheit, nighttime 64 Farenheit.

Ok, so new grower, I've had one harvest so far and am close to my second one. Here's what I'm seeing :
(err,attaching pictures, not sure where they will show)

Anyways, about 8 days ago these plants didn't look nearly as bad. I saw the tips burning and figured
it was nutrient burn, so I've been flushing them with just tap water(150ppm in base tapwater), ph'd, for the last 8 days, and the problem has gotten way worse. Had I overfed them so badly that 8 days of flushing still wasn't enough to stop this process? Or is this actually deficiency problems? Or a combination of a bunch of things?

I'll welcome any ideas. Thanks again.

Those plants are hungry..... Are you sure they weren't hungry 8 days ago, mistaken it for nute burn? At the stage those plants are at they can get pretty hungry. You are robbing yourself of your yield. You want to have these plants on cruise control right now, right through chop time..... I would start feeding again with a half dose of your a,b, and cal-mag. Next feed raise it, keep doing that until she gets a decent green back to her. Not too green, you don't want too much N in late flower. Once your happy with N intake, I would still up the part b and cal-mag if needed because your running qb's. You still have a few weeks to go and you can come back from it, but feed them!

Ok, first two answers both said feed. I'll hit'em with half dose today, then up it but keep N down. yeah, I'm hoping to feed these for another weekish
and then flush for day or two and harvest. Darn, it's hard to tell the difference between excess and deficiencies.. I really thought burnt tips meant too much
nutes.

It usually does but just the very tip, at first anyway. You're going to be ok, and you're still learning so don't beat yourself up too bad. Coco can be a challenging medium too grow in, so having a little misdiagnosis as your biggest problem isn't so bad.

Thanks. Ok so I fed them with a light feeding of 400pm, the runoff was 500pm.. just seems weird to have higher runoff after such a long flush?

you are seeing potassium deficiency and you have already been guided in the right direction. have fun with the grow!

Damn it ... beat me to it ... potassium deficiency as stated. Similar “ leaf burn “ like symptoms, but also is evident at the edges ( sawtooth ).

Bump up the bloom to correct . Flowers are demanding more.

Ok thanks for the reassurance , I'll bump up flower nutes for the last week, and get a day or two of flush in before harvest.
Wonder how much weight I lost Oh well, live and learn.

So since runoff is coming out higher, is it possible it's just pulling out old salts? or the excess nitrogen ones? Or should
I really not worry about runoff in Coco at all?

They look over fed to me but I have no idea how much you were feeding them. They should survive to finish out.

My two cents: First off you're screwing yourself by 'flushing' with plain water...you're stripping your medium of all it's nutrients "I've been flushing them with just tap water(150ppm in base tapwater), ph'd, for the last 8 days, and the problem has gotten way worse". If you feel the need to 'flush' do it with a 25% feed solution, but never with plain water. Hopefully you're not allowing the coco to dry out, or this is going to burn your plants as well. More importantly, you are way too close to the finish line to worry about dumping more N into them. Your plants are near the end, they don't need nor do they want N. Your plants look short on Mg and perhaps Potassium. The problem is coco over time will let go of Potassium, so most likely what you're seeing is an issue exasperated by your 'flush'. Keep in mind you're so close to the end, no magic potion is going to correct what you have at this point, so don't throw the kitchen sink at her. Go back and review your notes, try to determine where you may have gone wrong and use the lessons for your next grow. You'll grow even better stuff the next time. If it were me, I would feed a 25% feed solution moving forward until they're finished, but nothing more; it's not needed. Despite what you're seeing, your plants aren't that bad, so breathe, relax and enjoy your harvest; it won't be long.

kuruth said:

Coco+perlite, Canna A+B+cal mag, 3 gallon fabric pots, 500w quantum board, 3x6 closet
12/12 lights
starting 8'th week of flower, photo period kandy kush
average RH 55%, daytime 77 Fahrenheit, nighttime 64 Farenheit.

Ok, so new grower, I've had one harvest so far and am close to my second one. Here's what I'm seeing :
(err,attaching pictures, not sure where they will show)

Anyways, about 8 days ago these plants didn't look nearly as bad. I saw the tips burning and figured
it was nutrient burn, so I've been flushing them with just tap water(150ppm in base tapwater), ph'd, for the last 8 days, and the problem has gotten way worse. Had I overfed them so badly that 8 days of flushing still wasn't enough to stop this process? Or is this actually deficiency problems? Or a combination of a bunch of things?

I'll welcome any ideas. Thanks again.

Click to expand...

You saw a burnt tip and thought it's a burn. In mid-flower, like you were, burnt tips don't always mean a burn, it's usually a lack of potassium (can be sulfur as well)...and by flushing uselessly, for 8 days nonetheless, you have starved the plants, namely of potassium, hence why you see the excess burning. A potassium deficiency will start slowly with slight paling at the edges of the leaf and burnt tips! Then it becomes necrotic like yours. Stop the flushing...it's most often useless and causes more harm than good! Up the potassium!