Leaves curling upwards in young plants?

Looks like the leaf margins are rolling. Could be the VPD, could be broad mites, could be heat. What are you temps & relative humidity?

Seamaiden said:

Looks like the leaf margins are rolling. Could be the VPD, could be broad mites, could be heat. What are you temps & relative humidity?

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Thanks for the reply. I checked for broad mites with a looking glass but didnt see anything . Temp is 24 C , humidity - I don't have a way to tell. My previos crop had 1-2 incadescent bulbs on the floor to keep the temp up which I imagine dried the air too- and the plants were fine. On this grow I have only CFL so the humidity should be higher than the previos grow. And whats VPD ?

VPD (vapor pressure deficit) is a real thing.
It's an explanation for why our favored plant likes its temperature and RH in a specific proportion.
There's a chart that roughly targets low 70s (deg F) and in the 50s for RH as the sweet spot.
So if your RH is low, it might well explain your curl.

sspitfire said:

Thanks for the reply. I checked for broad mites with a looking glass but didnt see anything . Temp is 24 C , humidity - I don't have a way to tell. My previos crop had 1-2 incadescent bulbs on the floor to keep the temp up which I imagine dried the air too- and the plants were fine. On this grow I have only CFL so the humidity should be higher than the previos grow. And whats VPD ?

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What's the magnification of the looking glass? It needs to be rather high to see broad mites. I don't think you have them right now, but almost anything is possible. I'm leaning more towards VPD. Can you get one of those cheap temp+RH monitors?

Seamaiden said:

What's the magnification of the looking glass? It needs to be rather high to see broad mites. I don't think you have them right now, but almost anything is possible. I'm leaning more towards VPD. Can you get one of those cheap temp+RH monitors?

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I can get one from ebay but it will take around 20 days to get here. I watered them today - that should raise the RH(which I assume is relative humidity) for some time. So if I see any difference then thats the reason - am I thinking in the right direction ?

Watch the new growth closely for more crinkling and curling. That will be one tell of broads. Otherwise, play around with temperature and adding humidity, say by hanging up a wet towel or putting in a baking tray filled with pebbles and water, or even just putting in a humidifier.

Iv noticed the temp in my back room getting colder the last few days, what I gather from a few articles I read is that with higher heat more humidity, with lower temps less humidity, I'd say 70° F during th day, and dropping to 66-70 at night. Is this why my re-veg plt's leaves are curling up...?

Possibly, but in my experience *all* revegging plants act super weird, and to my eyes what you're showing isn't abnormal for a reveg.

Seamaiden said:

Possibly, but in my experience *all* revegging plants act super weird, and to my eyes what you're showing isn't abnormal for a reveg.

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What would be an ideal temperature, and how about the max, I live in tx, hot and humid. What temperature will kill plants...?

If the roots are kept cool, they can handle quite a bit of heat. I've only ever been able to kill them by thirst, or heat if potted. If growing inside then tolerable parameters are tighter, by quite a bit. So if OD they can easily handle temps into the 90s or even above, I side they'll practically melt (without CO2 supplementation).

Optimal RH seems to be debatable, but for inside I like temps in the 70s and RH values kinda high, above 60%. Most other growers do not, a new in a naturally high humidity situation it is probably better to get it to 50% or below. Keep in mind, I've grown hot, I've grown cold, but don't have high humidity in my location. So if you find another Texas grower with different advice, follow it, it makes a difference.

Thank you.It has been raining all week so the humidity outside is rather High, temperatures in the 80s to 90s, But on a hot day over 100 . I have had my grow inside, but I had to move em, put a timer on my Light, these are day 2 in my shed...

Rule of thumb for F is 95 + will severely slow the growth and will result in stress damages where 75 F and below will result in the same, below 65 F could obliterate plants. Ideal is 80 - 90 or where your body feels very okay-ish. :)
Humidity is an odd and maybe mostly strain dependent? I've vegetated plants at 60 - 80 % for a few weeks, no problems at all.

Below 65*F doesn't obliterate them, but the results are definitely less than stellar.

Update, not a good one... Help... Seems to be only new growth, older fan leaves looking good only 1 or 2 showing yellow spots... New growth, texture feels leathery

Pretty sure that plants getting cooked in your shed...Need ventilation man. Get those temps down.

Older fan leaves, been on 12/12 about a week

LittleDabbie said:

Pretty sure that plants getting cooked in your shed...Need ventilation man. Get those temps down.

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My buddy took and froze a milk jug of water, put it in a styrofoam cooler with a fan, dawn near blew colder than the ac in my burban, now replace the milk jug with dry ice, co2 for plants and AC...?

A/C and a fan should be enough.

I have a fan blowing on em now, shed is 10 X 10 X 8tall.... Built a grow box 7'long X 2'deep X 4'tall, was originally going to stand it up, was gonna wait till they got bigger. Anyway, a box inside a box, thermometer inside grow box stays under 95°f