CFL growlights - leaf stress

Photos show heat distress - i think - smaller plants handle close CFL lights - but growing plants show increasing stress.
Would like to have an opinion from someone please!

How far away are your lights?

They are CFL lights - and i had them a foot away from the plants for about a month before they started showing signs of stress. Have now moved them 2 feet away and put a fan in and vented the grow tent.

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Most cfls should be able to get within a few inches. Not all but most. You may have better luck submitting a support ticket in the forum.


Use the search bar and type in support ticket. It will lead you to the thread you need.

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COPY/PASTE the below list into your forum post.

Answer these simple questions the best you can.

If you do not know, or do not use something; Just say so; Or post

NA (non applicable)

• What strain, Seed bank, or bag seed

• Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF

• Vessels: Pots, Grow beds, Buckets, Troths

• PH of Water, Solution, runoff (if Applicable)

• PPM/TDS or EC of nutrient solution if applicable

• Indoor or Outdoor

• Light system

• Temps; Day, Night

• Humidity; Day, Night

• Ventilation system; Yes, No, Size

• AC, Humidifier, De-humidifier,

• Co2; Yes, No

Always try to upload a clear picture of any issues you may have to allow the community to assist you.

Add anything else you feel would help us give you a most informed answer should be included. Feel free to elaborate, but short and to the point questions and facts will help us help you in a more efficient manner


Looking for support ticket too. That isn’t very common with cfl’s, what size are they?

CFL’s should only be used to start seedlings, you need better lights.

That’s not 100% true. I’ve seen many ppl grow great bud with cfls. It takes quite a few of them and they all have to be pretty close to the plants but it’s entirely possible to do.

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I bought a HPS - MH Superveg 250w and a ballast. I am trying to work out when exactly i should swap to this lamp - had thought it was for the flowering stage - but maybe i use it earlier - can you advise?
The CFL has worked very well - i have read a few reviews that say they are only good for seedlings - but i have had this light up close to 6 plants for a while and the growth has been excellent - up until the grow room just got too hot - and i have moved the light further away and vented the room - also put a fan on .

Any advice would be very much appreciated. The curling leaf problem seems to be better having moved the light away and vented the room. Would like to know when i should change to the HPS light…


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The CFLs i use are: Light Kit 300w 2700k & 6500k Dual CFL Lamp & CFL Reflector Wing.
The light is ‘dual’ so is meant to be used in both growth and flowering stage.

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Have a picture or a link? I’m not familiar with those.

edit… link removed

No product there when I follow

@dbrn32 i was able to see it. I screen shot it for you.

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Indeed big for cfl bulb, but still a little surprised at results. What were canopy temps like? When you say you put a fan in and vented the space, what did this look like?

I’m wondering if maybe there wasn’t enough air exchange and temps got high in addition to co2 being depleted.

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Hi Jake

I wonder if this photo will make things clearer.
I increased the air flow in the growroom and put the CFL light higher in the room. It is cooler now.
The new growth has tips that curl up - and growth has slowed too. The light is further away - but the curled tips do look like a reaction to heat stress.
The plants are in cannaterra professional grow medium and i have them in big ‘air pots’ - with holes all down the sides - so roots should be OK.

There is a fresh air supply so CO2 wont be an issue either. Any help you can give me i would appreciate!