Mag Def?

[Sloth]

This is a late flowering pineapple express auto on roughly day 75. She's in plant magic soil using plant magic old-timer nutrients under a 260w hlg quantum board. Temp 24-27. Humidity 50-65%.

Middle leaves are yellowing, some brown spotting on leaves. Some mild interveinal chlorosis on lower leaves as well as one leaf that is completely yellow . Purple petioles and slight purpling starting on the main stem. I initially though N Def but there has been slight clawing for a couple of weeks that is now getting better. I have been watering 10 litres each watering in the 11litre pot as I think salt build up is what was causing previous issues. My tap water ppm is 300+. Her last feed was 600ppm 1ml calmag and 3ml oldtimer grow. Runoff ph is consistently 6.5.

 

[Arthur]

Possibly a P deficiency, would be about the right time to present itself.

 

[Sloth]

Ahh, i hadn't considered this. I have always held off on bloom nutrients until they stop vertical growth but its harder to tell with this plant as it's just been growing slow for ages. I have watered with some magnesium and molasses as I didn't want to halt vertical growth early (as if 75 days is early) but I intend to start bloom nutrients next watering.

 

[namvet25]

Looks like nitrogen def along with cal def.Try and give her some nitrogen and raise your dosage of calmag to 1 tsp per gallon.Purple stems are normal in some strains so don/t worry.Continue with bloom nutes next feed after giving her nitrogen.

 

[Waira]

hey Sloth! ... yup, I'd say P and N defc. happening,.... N defc. causes overall leaf yellowing, no necrosis until well advanced; P defc. causes large patches of necrosis.. both are mobile, so that why the fans are getting tapped out so much,...
-- noted very high mineral content of your water, 300ppm is pretty rocky shit! I deal with that out here, it's a PITA, cumulatively can drive pH up and cause build-up of CaCO3 which also screws with nute uptake.... I'd look into cutting that tap water with RO/DI water, or the best deal is the self-fill machines and a big jug... i try to get my water base ppm to no more than 150ppm.... skip the Ca-Mg for now,....
Forget about "vertical growth", stretch is so variable strain to strain, pheno to pheno, it's not a good marker for when to start bloom nutes... when you get fuzzy crowns formed, that a good general guideline to switch over....

 

[Sloth]

Thanks for your responses guys - I had ruled out N Def because of the hooked leaf tips (pictured below) but it seems the only thing it could be.

My organic bloom fertiliser is 3-5-4, would this be adequate to get this plant healthy again? I intend to split my tap water 50/50 with RO and feed 3ml/L of the bloom fertiliser tomorrow - does this sound sensible?

 

[Mañ'O'Green]

I have never used Old Timer nutes but that is what their chart says 3ml/L. Here is a picture of hooked leaves of N toxicity for future reference. Your don't look like that to me.

 

[Waira]

...too much Ca can screw with uptake of P and K, plus that feed is pretty mild,.. organic? This might be why she's slow to respond to feeds,... do you have a TDS or EC meter? A run-off test might be in order,...and a flush if it's loaded up in there!

 

[Sloth]

Hey yeah it is organic and I am always scared of burning plants but I think I just need to feed this plant more. I flushed recently, bringing the ppm right down, the next feed was around 600ppm. I will up it to 4 ml next feed, which is the most I've fed an auto flower, she's a big girl though so guess she's hungry.

Would you defoliate this plant? I will open her branches up when I get some more stakes but she's very leafy right now.

 

[Waira]

she could use a trim,...-- a bit shaggy she is!