Famous last words heard by houseplants:
“Bright indirect light?” This spot seems bright enough.
Your interior light levels form the growth potential of the plant. Your care efforts realize that potential (watering, fertilizing, repotting). Good light is the PREREQUISITE for a plant to grow but the term “bright indirect light” fails to convey anything concrete. At worse, it makes you think just any place the sun doesn’t shine is considered indirect light. And our eyes adjust to a wide range of light levels so you will NOT feel the difference. Instead, those with huge, unobstructed windows and/or skylights are patting themselves on the back at how good they are with houseplants while those with smaller windows living between buildings are struggling to figure out why their fiddle leaf fig always ends up with 90% of their foliage lost.
Measure your light. It will explain the magic of the greenthumb.
Disclaimer: this article contains Amazon Affiliate links. Earnings from qualifying sales goes to support the work of House Plant Journal – thank you!
Step 1: Get a light meter and get to know how bright your indirect light actually is. Here are a few that I think work well:
This is the Dr. Meter LX1330B Light Meter that I’ve been using – pricing has been varying wildly on Amazon but it should be around $40-60.
The Urceri light meter also works well and has the advantage of automatic range selection. The only downside is the sensor cannot be pointed away from the screen so you may need to use the ‘hold’ function.
What about apps? Android devices do not have standardized ambient light sensor hardware and the iOS platform doesn’t give access to the iPhone light sensor, which means those apps are doing a rough calculation based on the camera brightness value. An app might be able to give you a rough idea, but a dedicated device will do the proper cosine correction for the angle of incident light (that’s what the white dome is for).
Step 2: Bookmark this page so you can look up the levels of indirect light necessary for various plants. I don’t have every possible houseplant but after reading a few of these, I think you’ll get the idea.
Commercial Light Levels: most of our typical “houseplants” are grown in greenhouses with varying layers of shade cloth. To give you a rough idea, “50% Shade” would measure to 5000 foot-candles (FC) and “90% Shade” comes to 1000 FC – this is the strength of the sun shining through different layers of shade cloth, which is a black net-like material. These numbers are easily searchable on the internet – I’ve included the source links where applicable. ***Don’t expect to achieve these light levels indoors from your indirect light.***
Interior Light Levels: plants can technically survive in a wide range of light levels so do not take the numbers listed here as prescriptive – they aren’t strict requirements. You should think of them as guidelines for good growth. Another consideration is that “good growth” is subjective as any plant will take the shape of its light situation – up to a certain point, it’s not entirely under your control! These numbers are gathered from my own observations and measurements. ***Use these as guidelines.***
How to measure: from the spot where your plant is sitting, while the sun is NOT in view, you want the measurement to be above the “good growth” foot-candle reading. Measure at different times of the day and in different weather conditions so you can get a sense for the average intensity of your indirect light. When the sun IS in view, you want the duration to be less than what is stated as tolerable – and if the sun will be in view for longer, then block it with a white sheer curtain.
If you appreciate a sensible and logical approach to houseplant care, I think you’ll enjoy my online course:
|Plant||Good Growth||Minimum for Maintenance||Tolerance of Direct Sun||Commercial Light Levels||References/Comments|
|African Violets||400 FC||200 FC||2-3 hours direct sun is tolerable||1000-1200 FC||https://mrec.ifas.ufl.edu/foliage/folnotes/africanv.htm|
|Aglaonema (Chinese Evergreen, and several species)||200 FC||100 FC||1-2 hours direct sun is tolerable||1000-2400 FC||Classical “low light” tolerant houseplant. Plant dies slowly below 100 FC and will look ugly after a year or two.||https://mrec.ifas.ufl.edu/Foliage/folnotes/aglaonem.htm|
|Air Plants (Tillandsia – many species)||400 FC||200 FC||3-4 hours direct sun is tolerable||3000-7000 FC||my air plant care video here https://youtu.be/sjNVLgEbvOY||https://bromeliadsocietyhouston.org/genera-intro/tillandsia/|
|Alocasia (several species)||400 FC||200 FC||3-4 hours direct sun is tolerable||2000-5000 FC (estimated based on ‘part shade/part sun’)||Leaves will very likely die back. Calmly repot the base into fresh soil and new leaves may sprout.||https://edis.ifas.ufl.edu/fp033|
|Anthurium (several species)||400 FC||100 FC||1-2 hours direct sun is tolerable||1500-2000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/anthuriu.htm|
|Aspidistra (Cast-Iron Plant)||200 FC||100 FC||1-2 hours direct sun is tolerable||2000-5000 FC||Classical “low light” tolerant houseplant. Plant dies slowly below 100 FC but will look fine for many months, possibly years.||https://ufdcimages.uflib.ufl.edu/UF/00/08/93/74/00001/EP14700.pdf|
|Areca Palm||400 FC||200 FC||3-4 hours direct sun is tolerable||5000-6000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/areca.htm|
|Arrowhead Vine (Syngonium podophyllum)||200 FC||100 FC||2-3 hours direct sun is tolerable||1500-3000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/nephthyt.htm|
|Begonia (several species)||400 FC||200 FC||1-2 hours direct sun is tolerable||2000-2500 FC||https://mrec.ifas.ufl.edu/foliage/folnotes/begonias.htm|
|Bird-Of-Paradise (Strelitzia)||800 FC||400 FC||4-5 hours direct sun is tolerable||2000-5000 FC (estimated based on ‘part shade/part sun’)||http://hort.ufl.edu/database/documents/pdf/shrub_fact_sheets/strrega.pdf|
|Calathea (several species)||400 FC||200 FC||1-2 hours direct sun is tolerable||1000-2000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/calathea.htm|
|Cordyline (Ti Plant)||400 FC||200 FC||3-4 hours direct sun is tolerable||3000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/cordylin.htm|
|Croton (several species)||800 FC||400 FC||4-5 hours direct sun is tolerable||3000-5000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/crotons.htm|
|Dieffenbachia (Dumb cane; several species)||400 FC||100 FC||1-2 hours direct sun is tolerable||1500-3000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/dieffenb.htm|
|Dracaena (several species)||200 FC||100 FC||3-4 hours direct sun is tolerable||2000-3000 FC||Very low-light tolerant – I’ve seen one last for years at 30-50 FC. It had very long, thin and dark green spindly foliage but it was alive.||https://mrec.ifas.ufl.edu/Foliage/folnotes/dracaena.htm|
|English Ivy (Hedera helix)||400 FC||200 FC||2-3 hours direct sun is tolerable||1500-2500 FC||lower leaves will drop off – generally doesn’t look nice after a year.||https://mrec.ifas.ufl.edu/Foliage/folnotes/english.htm|
|Hoya (several species)||200 FC||100 FC||3-4 hours direct sun is tolerable||1500-2000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/waxplant.htm|
|Ferns (Boston Fern, Bird’s Nest Fern, Maidenhair Fern)||200 FC||100 FC||Bird’s nest fern/maidenhair fern – 1-2 hours direct sun is tolerable but must keep soil evenly moist||1500-3000 FC||my Maidenhair fern care video here: https://youtu.be/Q1FecMy2zXE||https://mrec.ifas.ufl.edu/Foliage/folnotes/bostonF.htm https://mrec.ifas.ufl.edu/Foliage/folnotes/birdnest.htm|
|Ficus (Rubber plant, elastica; Fiddle leaf fig, lyrata; benjamina)||800 FC||400 FC||3-4 hours of direct sun is tolerable||2000-6000 FC||if you don’t have at least 400 FC of indirect light, your fiddle leaf fig will lose most of its lower leaves. If you have small windows, save your money.||https://mrec.ifas.ufl.edu/Foliage/folnotes/ficus.htm|
|Fittonia (Nerve Plant)||200 FC||100 FC||1-2 hours direct sun is tolerable but must keep soil evenly moist||1500-2500 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/fittonia.htm|
|Maranta (Prayer Plant)||200 FC||100 FC||2-3 hours direct sun is tolerable||1000-2500 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/maranta.htm|
|Monstera deliciosa||400 FC||100 FC||2-3 hours direct sun is tolerable||1000-2500 FC (estimated based on ‘shade/filtered sun’)||my detailed monstera care article – https://www.houseplantjournal.com/2017-1-25-monstera-deliciosa-house-plant-journal/||https://edis.ifas.ufl.edu/pdffiles/HS/HS31100.pdf|
|Norfolk Island Pine||400 FC||200 FC||2-3 hours direct sun is tolerable||5000-6000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/norfolk.htm|
|Parlour Palm (Chamaedorea)||400 FC||100 FC||1-2 hours direct sun is tolerable||1500-3000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/chamaed.htm|
|Peace Lily (Spathiphyllum)||200 FC||100 FC||1-2 hours direct sun is tolerable||1500-2500 FC||Very “low light” tolerant – down to 50 FC, but will just barely survive and have high risk of root rot. Overall plant will gradually lose leaves and become thinner in low light. My peace lily care video – https://youtu.be/GpIsAhmWDbQ||https://mrec.ifas.ufl.edu/Foliage/folnotes/spathiph.htm|
|Peperomia (many species)||200 FC||100 FC||2-3 hours direct sun is tolerable||1500-3500 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/pep.htm|
|Phalaenopsis (Moth Orchid)||400 FC||200 FC||2-3 hours direct sun is tolerable||1000-1500 FC||http://www.aos.org/AOS/media/Content-Images/PDFs/GrowingtheBestPhalsPart_3.pdf|
|Philodendron Vines (Heart-leaf, Brasil, etc)||200 FC||100 FC||2-3 hours direct sun is tolerable but leaves may lose color.||1500-3000 FC||Very “low light” tolerant – down to 50 FC, but will just barely survive.||https://mrec.ifas.ufl.edu/Foliage/folnotes/philo-hl.htm|
|Philodendrons (Moonlight, Imperial Red, Prince of Orange, Pink Princess, etc.)||400 FC||200 FC||2-3 hours direct sun is tolerable||1500-2500 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/philo-sh.htm|
|Pilea (Aluminum plant, cadierei and others; NOTE: Pilea peperomioides not specifically mentioned)||400 FC||200 FC||2-3 hours direct sun is tolerable||1000-2000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/pilea.htm|
|Polka Dot Plant (Hypoestes)||400 FC||200 FC||2-3 hours direct sun is tolerable||3000-3500 FC||should be cut back every few months to keep bushy, otherwise will grow leggy.||https://gpnmag.com/article/culture-report-hypoestes-hippo-series/|
|Pothos (Epipremnum aureum, Scindapsus pictus)||200 FC||100 FC||3-4 hours direct sun is tolerable||3000-5000 FC||Very “low light” tolerant – down to 50 FC, but will just barely survive.||https://mrec.ifas.ufl.edu/Foliage/folnotes/pothos.htm|
|Sansevieria (Snake Plant, Mother-in-law’s Tongue)||200 FC||100 FC||5-6 hours direct sun is tolerable||1000-6000 FC||Very “low light” tolerant – down to 50 FC, but will just barely survive and be at high risk of root rot. New leaves grown at low light levels will be long, thin and floppy.||https://mrec.ifas.ufl.edu/Foliage/folnotes/sansevie.htm|
|Schefflera (Mini Umbrella Tree, Schefflera arboricola; Umbrella Tree, Brassaia actinophylla)||200 FC||100 FC||2-3 hours direct sun is tolerable||5000-7000 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/scheffle.htm|
|Schlumbergera/Rhipsalidopsis (Christmas/Thanksgiving/Easter Cactus)||400 FC||200 FC||3-4 hours direct sun is tolerable||1500-3000 FC||https://www.plantgrower.org/uploads/6/5/5/4/65545169/holiday_cactus_production_guide.pdf|
|Spider Plant (Chlorophytum)||400 FC||200 FC||2-3 hours direct sun is tolerable||1000-2500 FC||https://mrec.ifas.ufl.edu/Foliage/folnotes/spider.htm|
|Staghorn Fern (Platycerium)||400 FC||200 FC||3-4 hours direct sun is tolerable||1000-2000 FC||my staghorn fern care video here: https://youtu.be/bTM3WLwfq78||http://edis.ifas.ufl.edu/mg015|
|Succulents (Aloe, Echeveria, Euphorbia, etc.)||800 FC||400 FC||5-6 hours direct sun is tolerable||5000 FC||Aloe and Euphorbia can stay looking mostly the same down to 200 FC; Echeveria will stretch when grown indoors after several months – it’s inevitable. You can propagate by taking leaf cuttings and stem tip cutting – they simply do not stay compact and cute forever. Here’s a video on succulent leaf propagation: https://youtu.be/laAtQf8kwEA||https://hort.ifas.ufl.edu/floriculture/pdfs/crop_production/Cacti%20and%20Succulents_ENHFL04-006.pdf|
|Yucca||800 FC||400 FC||3-4 hours direct sun is tolerable||6000-7000 FC||often confused with Dracaena fragrans (Corn Plant), which is far more low-light tolerant. Yucca will not perform well below 400 FC.||https://mrec.ifas.ufl.edu/Foliage/folnotes/yucca.htm|
|ZZ Plant (Zamioculcas zamiifolia)||200 FC||100 FC||3-4 hours direct sun is tolerable||1000-2000 FC||often classified low-light tolerant, ZZ plant will survive with 50 FC but will be at high risk of root rot.||https://edis.ifas.ufl.edu/ep252|