Leaves curling from heat?

[getafix]

Hi guys,

Please help. This is my first grow under lights, and these plants have just been moved in after their first few weeks in the sun. The leaves seem to be curling up...

They are Malawi Gold and MOD surprise under a 250 HPS bulb. I tried moving the lights higher, about 50cm from the plants but the leaves keep on curling up like this. Is it the heat? The leaves are also a bit too green (excess N?) and there are some red/brown spots on the bottom leaves.

What are the right distance for the plants from a 250W bulb?

Ciao

 

[vavwl]

how large of an area is the light in? and what kind of ventilation do you have? Thats definetly heat stress.. pretty bad as well. Look into increasing ventilation, put a fan over the canopy of your plants, and maybe even put your light in a cool tube, or air cooled hood.

 

[MTF-Sandman]

Yup, it's heat stress...what are the temps, RH% and airflow like?

If you've got a fan blowing directly on the plants it can make the problems worse since it'll force the plants to transpire water faster...also low RH will compound this issue.

 

[sproutco]

What are you feeding the plants and how much? Do they contain micronutrients: iron, copper, manganese, zinc, molybdenum, and boron? What is the ph? Directions for testing are below in my signature. Are you letting the pots dry out enough? Be careful not to overwater since they arent in the hot sun anymore. What is in your soil mix? Dolomite lime for example.

 

[BLunTeD4LifE]

i am experiencing this exact same problem with some G-13x BSH that i have growing atm,,,,

it was definitely caused from heat stress...

i think ive got the problem solved now...

 

[getafix]

Thanks guys. I think the consensus view that heat stress is the problem is spot on. The plants are in a closed room about 3x3m. The room is getting very hot. I’m a bit worried on how to cool down the room and later the closet (as the grow closet needs to be closed soon). The plants were busted in my garden and now I am super paranoid having the room busted as well. Any ideas on how to solve the plants overheating??

Blunted, how did you manage to solve your heat prob?

Sprout, I use BioBuzz BioGrow and FishMix. The soil is 75% peat and 25% perlite/vermiculite. Does that sound OK? I will keep the watering in check, thanks.

MTF, what is RH%? I would have liked to get a fan blowing over the babies to help them out. What do you suggest?

Thanks vavwl, I’ll look into a cool tube. The ventilation is pretty bad

 

[BLunTeD4LifE]

i just raised my light, and got a small fan setup to blow directly over the canopy...

im using a 250w growking blue spectrum CFL in a 2ft x 2ft space... temps still arent where i want em but its gonna have to do for now,,,

i really should add some proper ventilation in my veg cab,,,

i have a 400w HPS in my flowering cab.. my flowering cab is 3ft x 1.5ft and when i first set that up i had a standard reflector, and i was getting major temp issues in there also,,, but i went out and got a cooltube reflector, and that got the temps down to acceptable levels...

also... RH = relative humidity....

 

[dre86]

Add this:

or this:

Will make a BIG difference

 

[MTF-Sandman]

Outta curiousity, how hot is "very hot"? Plants can handle higher temps with slightly higher humidity (RH%), but if it's dry and hot they'll transpire water too fast.

What's you're intake/exhaust like for your grow area?

 

[Blackmelo]

sounds like he has no intake or exhaust at all...

biggest problem is heat of course but just as bad is the fact that the plants won't receive any fresh air to photosynthesise.

 

[sahima]

You need to buy a thermometer and a humidity meter(if you haven't already), it will help you identify and solve such problems faster.
For now do what others said, a fan and fresh air.

By the way the closer, the heat permits, for the lamp to be the better.50cm is a bit far for a 250, AFTER you solve your heat problem you can move the lamp closer. I would say 20-30 cm away from the plants is ideal for a 250, ( if your temps stay under a maximum of 30C degrees). Greetings

 

[getafix]

I'm going to go and get a RH and temp meter as soon as possible (when I get a chance to pop over to civilization for a day)

I think the temp in the room got into the 40s Celcius I should have known I just got myself a 40cm fan and wil set it up tomorrow. Tonight the babies are chilling-off outside.

I am planning on having the lights and fan on from around 18h00, when I get back from work, until around 7h30, when I leave for work. That will also help, 'cause the days here are damn warm, even without the lamp. I will leave the room door open for ventilation while the light is shining. Maybe keep open the window during the day...

Blunted, do you have an exhaust or intake from outside?

 

[Erin Kerrik]

Leaf margins curl up when they're trying to retain moisture, for whatever reason.

 

[getafix]

Thanks guys. The fan is working well, keeping the temps down. The plants are looking much better!

 

[afropips]

Hiya G,
I am sure I advised on a fan & ventilator a while back!
Have the fan positioned on the light so it moves the bulk of the heat
away from the light.

If you have your light on in the daytime hours keep the door of the closet open &
the fan oscilating & it will solve the ventilation problem.

I would wake up the plants by turning the light & fan on manually at 7.30 am after opening the closet door.
water each plant apx 0,5 litre of water each morning.
Let the light do the trick while the fan oscilates.
You should be able to move the light as close as 30 cm
now you have the fan pointing on the light.
You could automate the process & invest in a timer & relay for the fan & light but you will still have to open & close the closet.
At 7.30 pm put the plants to bed by turning the light & fan off & closing the closet
so they get 12 hour of darkness. This will cause them to flower early & not get so big.

Add some reflective material on the inside of the closet or paint it white.
Get a blanket to cover the closet at night so no light enters the closet
if you are using the room at night.

Hope that Helps Bru!

Cool Runnings..........

 

[getafix]

Thanks Afro. The plants seem to have taken real punishment from the heat stress and the stretching during the prolonged time in the darkened room.

The 2 plants in the guerilla grow are doing great. I'm just worried about hight and pests...

 

[CheeseNstomata]

Dude that is curled,Ya got new pics of em now
Do they uncurl ??

 

[getafix]

Yea man. They take a few days (about 3-5) to recover, but now they are back to normal (uncurled). I'll take some pics and post them...

 

[CaptJamesTKirk]

The plants were busted in my garden and now I am super paranoid having the room busted as well. :

One "bust" should be a warning - the second may not leave you as happy - straighten up - think

Moving plants from out door to indoor is stressful - heat is stressful and lack of vent is stressful. Your not ready to be growing indoors - especially if somebody knows you were growing and the plants "disappeared"

loose the grow - tempararly and start acquiring the needed equiptment. Growing is a learnig thing - so is jail, don't be goofy

 

[getafix]

Cpt Kirk,

I agree with you. I am thinking of my fiance and the stress and sh!t it would cause if I get bust.

So I've planted all except 2 of the plants in a guerilla grow spot a few kms away from home. I am now working on fixing the cab and using the 2 plants as my test subjects.

I believe the 2 plants should not land me into too much hot water...