Almost every single experienced grower will tell you that you can’t get anything decent from incandescent bulbs.
I would tend to disagree. Incandescent bulbs do indeed have a use. In grows with limited wavelength output (LED, fluorescent, induction,) you may just wish to supplement with a few cheap incandescent bulbs. of low wattage. Tungsten filaments have a fair emission peak around 630nm, which is a highly-efficient wavelength in the red range for plant photosynthesis, and tungsten filaments emit a large amount of IR light from 720-760nm, which can help promote fruit and flower development.
Bearing this in mind, I most certainly would not recommend using incandescent lamps alone, and certainly don’t use high-wattage ones. 10-25w, no more. You need to be able to get these close but not burn the plants. Don’t overload on these, either, let your other lighting carry the grunt work, the incandescent lamps are just supporting lights.
Stay tuned for another Ask Alex. As always, comments, questions? Let them rip below!