DrMistry

Good evening to you all!

I have 2 ladies which are 3 weeks in to flower, and yesterday I noticed some corkscrewing of leaves along with some cola leaves curling upwards as well as downwards. Being a good boy scout I got the pH meter out and *gasp* the soil in one pot was REALLY low (between 3 and 4) and the other was only slightly better at about 4.5 - lower down in the pots is more acidic. I've been using a mosture meter to make sure I'm not over-watering and there's plenty of perlite in the soil so I don't think there's rotting root matter in the bottoms of the pots, so I flushed them pretty thoroughly with water which tested at pH 6.5. However today the leaves haven't really recovered, and I'm seeing severe lightening of the tallest growing tips. I gave the 2 girls a foliar feed of epsom salts and a tiny bit of zinc (couldn't remember if zinc's mobile but I didn't put much in anyway) and a very mild 5-7-10 plant food. pH of the foliar feed liquid is just below 7. Was this a bad idea?

I'm thinking that the acidity of the soil has locked a lot of nutes up in the soil, and was hoping that the flush had taken care of the acidity, but today the pH in both pots is still too low - both at 4.5 and simpoms of the plants getting slowly worse (not life-threatening yet but I want to get it sorted as soon as possibly).

Here's one cola which is showing "talon leaves", or "claw leaves" as I've also seen them called :



Next up, and on the same plant, is another cola who's leaves are curling UPWARDS rather than down. At this point my head was spinning like a crow on speed!



And finally here is the yellowing of one of the taller colas. Growth has slowed dramatically, and for the last couple of weeks the lower leaves have been yellowing up, shrivelling and dying. I wasn't too worried about this at the time, thinking it was an engineered N defficiency which I wanted going in to flowering.



I've been feeding them with the aforementioned 5-7-10 food since about 2 weeks ago, and before then I was using ammonium sulphate to suppliment the 5-7-10 food, which had been working out very nicely - pH was stable at 6.5, growth was good and the only other problem I've had was a zinc and mag shorage which I fixed with one watering/feed about 2 weeks before they went in to flower.

Now I'm left wondering a) if I should have kept up with the zinc and mag, b) what's caused the acidity of the soil and c) why flushing doesn't seem to have mitigated the problem. Also at the back of my head I'm wondering if I should repot but I'm worried it'll stress the plants while they're flowering, with all the attendant joys of hermaphroditism!

Anyone got any ideas? I'm going loopy here!

__________________
Regards,

The Good Doctor.
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"The use of words to convey something other than their literal meaning? Now that is irony!"

DrMistry's Nice-and-Easy LST Grow, day-by-day
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dontask

Sorry I dont have time to go into more detail, but heres a quick thought.

Find some high quality fine-ground dolomitic lime and attempt to evenly but mildly apply it into the soil matrix.

Stop the ferting until you get the pH under control.

If you can, use pH 7.5 RO water at a slow steady pace to help keep the roots from burn until you can fix the prob.

The best route to go if you truely want to save these plants is a major transplanting involving new soils ( with lime! ) and careful feeding.

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* Anything I say is a result of complex chemical and electrical reactions occuring in my brain and should not be taken as any sort of tangible existential proof.

Xgone.

hey doc,

What's the temperature @ the top of the canopy, what size light are you using and how far away is it from those scorched tops? That looks like a combo of nute burn and heat stress but mainly heat stress. If it's not hot they you need to go flush...badly.

And why are all the leaves saturated with water? There's really no need to be misting...

DrMistry

Hey fellas, thanks for the posts.

The light is a 400w HPS, currently a good 16 inches from the plant tops. Air temp at plant tops is 22c "night time" and 28c at the absolute max when the lights are on. The soil temp has been a rock-solid 22c for as long as I've been measuring it. I'd been allowing temps to rise to the 28c level in order to try and dry the soil a little quicker (along with an extra fan) so I can flush again before the weekend without drowning the roots. I'd been misting the leaves to try and relieve what I thought was a mag defficiency, but looking back this was a dumb idea, especially while the girls are budding. Should I go ahead and flush again even though the soil's still pretty wet from the last go?

For the most part the plants look resonable enough, but the more I think about it the more I believe that repotting with clean soil, reducing the temps and backing off nutes is the way to go...wondering if the ammonium sulphate built up to a critical level and sent the pH runaway. Off to the FAQ I go!

__________________
Regards,

The Good Doctor.
------------------------------------------
"The use of words to convey something other than their literal meaning? Now that is irony!"

DrMistry's Nice-and-Easy LST Grow, day-by-day
------------------------------------------

DrMistry

I bi the bullet and repotted the two girls. Nice, fresh, clean potting soil, at 7.5 pH was used, and I *very* gently shook as much of the old acidic soil as I could away from the rootball. I've watered them in pretty firmly, and the water draining from the bottom of the pots was slightly acidic, but the medium is now reading a steady 7 all the way down the pot. No nutes for a week is what I'm planning, and I'm watching them like a stoner hawk for signs of excessive droop and all that. Cheers for the help everyone, I'll update this thread when I have a definitive result one way or the other...good job I got some solid clones last time round so if the worst comes to the worst I'll just have to start again!

Should have said - I looked at "Transplanting 101" in the Hall of Great Threads for some confidence-boosting info.

__________________
Regards,

The Good Doctor.
------------------------------------------
"The use of words to convey something other than their literal meaning? Now that is irony!"

DrMistry's Nice-and-Easy LST Grow, day-by-day
------------------------------------------

dontask

Well done young Padawan.

Good luck with the shrubberies

__________________
* Anything I say is a result of complex chemical and electrical reactions occuring in my brain and should not be taken as any sort of tangible existential proof.

DrMistry

A-ha, yes well there we are! After having to go out for a couple of hours, I was somewhat nervy about poking my head in to the grow room this evening...but I need not have been, and in fact the Dreaded Claw has started to uncurl and things are looking perky all things considered. pH is sitting steady at 7, there's far less wilt than I thought there would be, but just to be extra safe I've lifted the light another half a foot and I'll be watching the temps tonight.

Thanks again to all for the advice!

__________________
Regards,

The Good Doctor.
------------------------------------------
"The use of words to convey something other than their literal meaning? Now that is irony!"

DrMistry's Nice-and-Easy LST Grow, day-by-day
------------------------------------------