Leaf margins rolled upwards, droopy leaves...pics.

[MusicalTrips]

I'm growing two BigBud #2 reg, two Afghani #1 reg, one CH9 Jack 33 fem and one NL x BigBud#2 fem.

The plants were all germinated from seeds on the 1st April.

This problem is affecting all of the plants, but the worst affected plant is the larger of the two BugBud#2 reg.

The humidity is quite low I think but i have no way of measuring this, so I have put bottles of water, wet flannels etc to try and bring the humidity up a bit.

I have a 6inch desk fan blowing over the canopy for circulation.

The light I'm using is a 400w HPS and is 2ft from the tallest plant (the worst affected BigBud#2). Temps are 25/27 degrees during lights on, and 18/20 degrees when lights are off.

I'm using soil, John Innes #3 with about 35/40% perlite.

I havn't watered with any nutes yet as the John Innes bag say that there is enough food in the soil for 5 weeks and I only re-potted them on the 8th May.

I have researched the leaf cupping and have found an array of causes of this.
So I'm looking for some advice from the pics I've uploaded.
I'm not a veteran grower and I'm always open for learning more about these amazing plants.

The first 3 pictures are of the BigBud#2 that has the worst cupped/drooping leaves, the last two pictures are of one of the Afghani #1's, it has a small amount of leaf edges rolling/cupping up, but the leaves also seem to claw down/under themselves.

I know the John Innes #3 may be a tiny bit too string for these young plants as it's meant for mature plants but it's all I could get hold of at the garden center and I didn't want to use the rest of my BioBixx Allmix as I don't think it's very good and the EC is way too high.


Thanks for your time, MusicalTrips.

[deran]

the leaf margins is where most "transpiration" occurs .. and you are right its the low humidity causing this

the leafs arent droopy, they bend to open up more stomata surface - to "breath" and "sweat" better

both solved with higher humidity

[MusicalTrips]

Thanks for the reply, is there anything else I can do to get the humidity up other than the bottles/cups of water and wet flannels?

I do mist with distilled water before lights on and after lights off.

Thanks, MusicalTrips.

[Cptn]

Please describe your ventilation system: intake air and exhaust air. What is your setup?

Vapor Pressure Deficit (VPD) is created when the room has too much vacuum (exhaust not properly matched with intake.) It leads to significantly lower RH.

Not sure if that impacts you, but it is a factor that can improve your environment if managed.

The bigger your plants get, the more vapor they will transpire into your room which will help a lot compared to where you are now.

Still, check for VPD and fix it if you got it.
If heat is a factor, increase intake capacity as needed till balance is achieved.

With my new exhaust fan, I can't run it faster than 70% without overpowering my intakes and creating vacuum.
I can make my ears pop with a twist of a dial :-)

[farmergiles]

Low humidity and/or too high temps.

Other than that they look very healthy.

[MusicalTrips]

CPT - I have a Hydrogarden tent 1.2 x 1.2 x 2m.

I have a 4inch/100mm carbon filter, attached to a 4inch/100mm RVK extractor fan pulling air out the tent and near to a window slightly open to vent some of it.

For fresh air intake I have the tent placed on the opposite end of the window with a window open to let fresh cool air in around the tent, plus there is a wall vent just above the tent with slats pointing downwards so theres always a supply of cool fresh air. I have no intake fans but keep the holes that are there for intakes in the bottom of the tent open during lights on and you can feel cool air coming in.
Though when these are shut you can see the walls of the tent really sucking in from the negative pressure created by the extractor fan. Is this a bad thing? I guess what you're saying is my extractor is taking too much air out and not enough new air is being pushed in?

I have a 6inch desk fan in the back corner blowing kind of across the top of the canopy and towards the light to keep the canopy moving and cool.

Thanks for the reply!

....................

FarmerGiles - Thanks for the input mate!


MusicalTrips.

[tnuc]

Originally Posted by MusicalTrips

CPT - I have a Hydrogarden tent 1.2 x 1.2 x 2m.

I have a 4inch/100mm carbon filter, attached to a 4inch/100mm RVK extractor fan pulling air out the tent and near to a window slightly open to vent some of it.

For fresh air intake I have the tent placed on the opposite end of the window with a window open to let fresh cool air in around the tent, plus there is a wall vent just above the tent with slats pointing downwards so theres always a supply of cool fresh air. I have no intake fans but keep the holes that are there for intakes in the bottom of the tent open during lights on and you can feel cool air coming in.
Though when these are shut you can see the walls of the tent really sucking in from the negative pressure created by the extractor fan. Is this a bad thing? I guess what you're saying is my extractor is taking too much air out and not enough new air is being pushed in?

I have a 6inch desk fan in the back corner blowing kind of across the top of the canopy and towards the light to keep the canopy moving and cool.

Thanks for the reply!

....................

FarmerGiles - Thanks for the input mate!


MusicalTrips.

there's been some good tips in this thread...take care with your venting and smells as you have the smallest sized filter...6" would be better and safer considering your plant numbers, size of tent and that you stay in a non legal part of the world...of course the larger fan/filter will reduce your humidity more than it already is but it's the lesser of the 2 evils...try and bounce the fan off the side of the tent creating a breeze rather than blowing it over the leaves..especially early on

[MusicalTrips]

tnuc - I agree there's some good tips being put out there for me I appreciate the help!

The smells are not a problem the filter I have is sufficient enough and hasn't let me down yet. If it starts letting a bit of smell out then I will just buy a fresh filter or maybe even have a go at getting it refilled, depending whats the cheapest/less dodgy.

As you saay the 6inch filter/fan would decrese humidity even more, so I don't think that is an option for me right now.

I will try having the fan coming off of the tent wall to see if that helps at all, I don't ever have it blowing directly onto the plants I know that's a no no.
I will be buying an oscillating cool air tower fan this weekend as the fan I have right now doesn't oscillate.

Thanks again for everybodys input!

MusicalTrips.

[deran]

I don't ever have it blowing directly onto the plants I know that's a no no.

do you think wind outside doesnt blows directly onto plants

keep your plants waving with your fan, they will like it ... it takes a lot of wind power until it gets contraproductive, normal fans just cant become hazardous to your plants

my input towards this is an ultrasonic fogger, not too expansive and very efficient raising humidity, put it infront of your fan, so the fans spreads all the fog around your plants .... or .. put more plants into your tent, both raises humidity

[Cptn]

Originally Posted by MusicalTrips

CPT - I have a Hydrogarden tent 1.2 x 1.2 x 2m.

I have a 4inch/100mm carbon filter, attached to a 4inch/100mm RVK extractor fan pulling air out the tent and near to a window slightly open to vent some of it.

For fresh air intake I have the tent placed on the opposite end of the window with a window open to let fresh cool air in around the tent, plus there is a wall vent just above the tent with slats pointing downwards so theres always a supply of cool fresh air.

if the intake and exhaust are the same size, it is harder to cause a VPD problem, especially when using a carbon filter. Add to that the use of a tent (which tend to have lots of places for air to sneak in) and it is highly unlikely you have a VPD problem.

Supplement humidity as best you can. As the plants get bigger, the low RH problem will potentially resolve itself as they transpire more into the air.