Light spectrum and bulb choices for houseplants

Tue. Jan. 9, 2018

Click below to listen to my 2 min Garden Bite radio show:  Light spectrum and bulb choices for houseplants

Yesterday I talked a little about the light spectrum for houseplants.  If you’re trying to get a houseplant to flower, ideally you’ll give it the full spectrum of light.  While you can achieve that with a combination of warm/soft bulbs and the cool/white bulbs you may consider full spectrum LED lights.   They cost more initially, but their cost savings over time makes it worth it, if you want that flowering plant!

According to a 2016 study, NASA scientists, found that LED lights provide the best source of lighting for plants cultivated indoors.  Better for plants, better for the environment. Further NASA research on the effects of different light spectra on plants found that red and blue lights offer the best support for photosynthesis, which is the process used by plants to transform light into the energy needed for growth and flowering. Further investigation pinpointed more specific effects of different light wavelengths on plants grown indoors.

Green Light was once thought not to be necessary for plants, but recent studies have discovered this wavelength penetrates through thick top canopies to support the leaves in the lower canopy. While not necessary in your home, it’s good to know!

I will also note that, if you’re goal is to start seeds indoors, then shop lights, those generally ugly lights hanging in your garage, are all you need.  They are cool, fluorescent, and cheap! Check the ends of your fluorescent shop light tubes.  If they’re turning gray to black, then it’s most likely time to replace them.  They’re losing their intensity.

Peppers on a heat mat under a shoplight

By the way, I’m not suggesting you start sowing seeds indoors yet.  If you start this early, you’ll get leggy plants that will likely be weak.  That or they will start to take over your home and that’s a whole other story!