Ask Alex #4: Can I use incandescent lighting to Grow Marijuana?

WSJ Team October 23, 2011 2

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!



  1. chINO August 1, 2014 at 8:25 PM - Reply

    hey thanks. I honestly believe you can grow a plant these with one two high wattage light bulbs and proper distance. just going to take a long time for regular seeds/clones. I am using this as a supplement with 180/300 led grow with few plants. its just 3 60 watt bulbs on a tall lamp with plastic shades. no where near close the plants to burn them. 10 sec check! remember. thanks alex. these lights with led should help my veggers get going quicker with leaf production.

  2. Kween Frostine February 4, 2018 at 12:43 AM - Reply

    I used one incandescent bulb to grow 2 plants from seed to a decently big vegetative size–several big fan leaves & a nice skunky smell. Unfortunately I had to abort the grow unexpectedly, but those bagseed plants responded wonderfully to that single weak lamp. I was shocked. And no, they didn’t stretch or fall over. I doubt it would be sufficient for flowering or maintaining growth of large plants, but it definitely works for seedlings & small veg plants.

    If your soil is high quality, incandescent lights can serve as a stand-in for sunlight or grow lights like CFLs when necessary.

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