When I grew in here all those years ago, I kept the door ajar most of the time and sometimes wide open during the dark period so there was plenty of air getting to the plant. I never used fans but there certainly wasn't a heat issue with just wimpy fluoro tubes. Medicaldelivery mentioned above that there could be mould issues but that wasn't the case. I've currently got just one of my blue CFL bulbs on above a couple of White Widow clones a friend gave me. One showing signs of root in the soil and the other still in some rock wool. Both showing new growth but I'm not getting my hopes up yet.

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