A question from a fellow grower:
When growing with cfls how many per plant and is it ok to keep the plant under the light for 24 hours
The total number of plants is more per square foot or square meter than per light and is highly dependent on your style of “cropping”, training and pruning. SOG style will have quite possibly many many more plants per square foot/meter than ScrOG, as an example. With the lights it is all about total lumens or FLUX per square inch or square cm than anything else. With regular off the shelf CFLs, one of the average “biggest” or most powerful you can find easily is the 45 watt and those would be used about one for every square foot or 9 per square meter evenly distributed
It is ok to keep the plant under 24 hours of light for the vegetative growth period. 12 hours or more of uninterrupted darkness is what gets the plant to flower. 12/12 being the most common for most of the flowering period. Most people believe most strains should get a little darkness even during the vegetative period, vegetative growth requires a significant amount of light above 12 hours and most believe giving at the very least 6 hours of darkness is important to overall health and so use a 18/6 for the vegetative growth period, the exception being autoflower strains that have a ancestry of growing near the arctic circle in Siberia and so like parts of Alaska, there may be up to 6 months of 24 hours of sun during parts of the summer and is why they have evolved the ability to to flower on a kinda set schedule even with getting 24 hours of light their whole life.