WHY THIS ? (PH ?) ????????????? (pics)

[Bulster]

Could someone give me a hint as to what's wrong with these plants?

I am relatively experienced but this is my first outdoor grow.

Indica dominant bag seed growing outdoors in the California sun in regular topsoil. I always water w. PH corrected water and started some light GH nutes a couple of weeks ago. Soil PH is quite a bit higher than what's optimal so I keep the water around 6.2 to counter that a bit without going overboard. They have been in this soil for at least a month now. Before replanting they looked normal and healthy.

Does this look like a PH problem/symptom? Usually I just see curly leaves when it's PH, not the folding up that you see here?

Or is it heat related because Indicas don't like heat? (we have 95 to 100 these days and low humidity.

Any other ideas?

[oldmac]

Leaves look like they are "canoeing" which is usually a sign of a ph problem, causes nutrient lock out. High heat might make it worst.

Keep in mind that heat has an effect on ph, most calibration solutions have a chart for temp compensation, your readings may be off. Especially if you calibrate indoors in ac then read 90 degree stuff outdoors.

Not sure what to reccomend, I might try adding some dolomite lime to the soil around the plant and go alittle higher with the water ph.

Wish I could be more helpfull, tho I'm sure someone else will chime in.
Good luck with it. :)

[killerweed420]

It also looks like it could be overwatering. How often do you water? I see what looks like mulch on the soil that helps water retention which is fine just don't water too much.

[Bulster]

Thanks killer, you just cemented my suspicion that this is a PH problem. Will be doing some testing and correcting.....

[Rusty Trichome]

How are you testing ph of the soil? (most soil ph probes are inaccurate pieces of junk)
How are you testing the water?

Have you tried running a cup of ph'd water through a pot (gallon) of your soil soil and see what the runoff reads? (only works with a ph pen)
You might be chasing an erroneous ph number, and as a result, might be adjusting ph out-of-range.

I grow in the SW desert where my growshed temps are scorching during the summer. My daytime temps top-out around 100 to 105 degree range throughout flower...with the a/c on. Humidity is virtually always in the low teens, except for the occational monsoon conditions. Been growing under these conditions for the better part of...IDK...7 or 8 years? A link for handling heat is in my signature.

I generally grow Indica's and Indica dom's in summer, sativa and sativa dom's in the winter. My indica's handle the heat better than my sativa's, but am able to bring either to the shed if necessary. :thumbsup:

How long have they been on "light" nutrients? Why...?

[headshake]

It also looks like it could be overwatering. How often do you water? I see what looks like mulch on the soil that helps water retention which is fine just don't water too much.


Thanks killer, you just cemented my suspicion that this is a PH problem. Will be doing some testing and correcting.....

umm, how exactly did killer's post lead you to believe it's a pH problem?

-shake

[oldmac]

I generally grow Indica's and Indica dom's in summer, sativa and sativa dom's in the winter. My indica's handle the heat better than my sativa's, but am able to bring either to the shed if necessary.

Hey Rusty,

That is the exact opposite of what I would have thought. I would have bet good money the sativa's would do better in the higher heat, I see I would have lost. Thanks for that, cause you the man when dealing with heat issues.:thumbsup:


Yo' 'shake,

(in my best Rodney Dangerfield voice) "I don't get no respect." LOL :D

[Rusty Trichome]

I thought so too, but have done repeated side-by-sides. Indica's were less prone to heat stress, and no adjustments of nutrients necessary. The already nutrient-sensitive sativa's are easily overnuted under the same heat stress. I still grow 'em both during the summer on occation, but with the full understanding that sativa dom's just don't look like they handle it as well. Strangely, no real difference in taste or quality though. (after curing, of course)

Perhaps it's a genetic reaction to UV light thing:
Structure-function relations of warm ... - Google Books (http://books.google.com/books?id=_TzSeUZAVq8C&pg=PA26&lpg=PA26&dq=leaf+structure+and+heat+stress&source=bl&ots=W2Qt3UjuDC&sig=HJgVbokKM6LIASZVW8ZLAPaqxCw&hl=en&ei=_duvSuiIKpD-tQP08pm8Cw&sa=X&oi=book_result&ct=result&resnum=7#v=onepage&q=leaf%20structure%20and%20heat%20stress&f=false)

Maybe this is why UV light affects our cannabis plants differently (different mixes of strains equals differeent results...?) But that's another topic. :thumbsup: Notice the mentioning of dead trichomes adaptations and light absorption or reflectivity...? Not at all sure what it would mean for cannabis, but who knows?

If you scroll down on the page to Section 2.1.2, it addresses the ability (or inability) of a plant to deal with heat. Doesn't mention a tropical temperate climate plant in an arid enviornment, though. Nor does it address an arid plants ability to shed water (avoid mold) in a humid enviornment. l really don't know much, other than what has been working in my growroom.

2.2.1 addresses arid-climate plants. This is where the narrow-leaf for arid (hot?) climate understanding comes in, but there are plenty of narrow-leaf plant species found in tropical/temperate regions too. Cannabis isn't necessarily an arid-climate plant, soooo...IDK.

I read this technical shit and it get's my mind going in a thousand directions. Time for some aspirin and a nap...
Sure wish someone would fund a legitimate cannabis biological research institute. I'd volunteer to be the custodian. (or perhaps the customer relations officer?) :jointsmile:

Sorry about the hijacking...

[Bulster]

HeadShake, to answer your question I already was pretty sure it was PH, was kind of looking for a second opinion and Killer was first to give me one.

RUSTY, awesome reply, no worries about the hijacking :-)
I test soil ph by checking the ph of some water and then using it to make a dirt 'slushy', then I stick my ph pen into the mush and extrapolate what the soil PH is based on the change in PH.
You also ask about nutes, here's the skinny: They are in clean topsoil. On top is a layer of composted horse manure and wood shavings. when I water the horse waste gets soaked and presumably leaches some Nitrogen down into the soil. But, I am in flower now so two waterings ago I started adding some GH MaxiBloom, roughly 300 TDS worth for a total of about 550 since my well water comes out at about 250 TDS.

Thougts?

I'll be doing a fresh PH test shortly....

[headshake]

HeadShake, to answer your question I already was pretty sure it was PH, was kind of looking for a second opinion and Killer was first to give me one.



i'm not knocking you or anything, but it was old mac that gave you the pH advice. killerweed's post made no mention of pH at all. that was my point. i'm not knocking you so please don't take it that way. i just think that you should give credit where it is due. that's all.

good growing!


-shake

[Bulster]

Thanks Shake, my mistake!!!

Oldmac, SORRY about that, all credit goes to you for chiming in on the pH question, Thanks very much.

[Bulster]

OK, here are the PH results:
Well water PH: 7.5
Composted Horse manure w wood shavings that I put on top of the soil, PH: 7.5
Soil: When mixing the 7.5 water with the soil and then testing the 'mud' it comes to 8.2, so I am assuming that my soil PH is at least 8.5 if not a little higher.

Make sense? Can I just keep watering with 6.2 water or would it be better to work some peat moss into the soil?

[polishpollack]

This plant usually cupps its leaves when temperatures are too high. That plant is probably getting full sun most of the day and is simply too hot for too long. Could probably use more watering to compensate. It could be to much fertilizer, but I doubt it. Most likely it's heat.