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.
The worst part is the term “bright indirect light” 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.
After measuring light, realized there’s no such thing as a ‘greenthumb’ – just people with large, unobstructed windows.
Step 1: Get a light meter and get to know how bright your indirect light actually is.
A light meter is so critical to understanding light that I designed and manufactured my very own:
The LTH Meter
Light | Temperature | Humidity
Disclaimer: this article contains Amazon Affiliate links. Earnings from qualifying sales goes to support the work of House Plant Journal – thank you!
This is the Dr. Meter LX1330B Light Meter that I used before. It’s not as compact as the LTH Meter, has limited measuring ranges (need to manually select the range), and does not measure temperature and humidity. The pricing has been varying wildly on Amazon but it should be around $40-60 [US Link] [CAN Link]. An alternate model: [US Link] [CAN Link]
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 natural light:
- Sensor placement: top of the plant
- Sensor orientation: should be pointed straight up but if you find that you have to turn the sensor to get a higher reading, it just means over time, the plant will tilt towards that direction
- WHEN to measure: the purpose of the light meter is to measure the strength of INDIRECT light so you want to get a sense of the average strength of this light while the sun is NOT in view (and also not too close to sun rise or sun set – when the overall sky is darker)
- DIRECT SUN: also take note of the total duration the sun shines directly on the plant
Analysis for natural light:
- If the average indirect light is above “Good for Growth”, then expect good growth
- If the average indirect light is at or below “Minimum for Maintenance”, then don’t expect strong growth
- If the duration of direct sun is above the “Tolerance of Direct Sun”, then block it with a white sheer curtain
- If the duration of direct sun is at or below the “Tolerance of Direct Sun”, then there’s no need to block the plant (just be sure to keep up with watering)
For white LED grow lights:
- For good growth: set the distance of the grow light such that the reading at the top of the plant is at or above “Good for Growth” and keep the light on for 12-16 hours a day
- For maintaining over winter: set the distance of the grow light to get a reading around the “Minimum for Maintenance” and keep the light on for 8-12 hours a day
Note on FC (foot-candle) vs PPFD (PAR Photon Flux Density)
After using a spectrometer, I realized that illuminance (FC and lux) and PPFD correlate nicely for natural light and white LED light (approximate PPFD = 0.2 x FC – for those two light sources). So as long as you’re using either of those light sources, you can use whatever light meter you have (traditional foot-candle/lux or PAR meter) and refer to the chart.
Discrepancies between FC and PPFD only arise when using these grow lights:
- Red/Blue (“blurple”) LED grow lights
- Ceramic metal halide
- High pressure sodium
So you can expect good growth results even if measuring with a traditional foot-candle meter as long as you’re using either natural light or white LED lights.
Note: the full unit of PPFD is “µmol/s/m²” but, for this chart, it is shortened to “µmol”
Looking for a sensible and logical approach to houseplant care?
Find it here:
|Plant||Good Growth||Minimum for Maintenance||Tolerance of Direct Sun||Commercial Light Levels||References/Comments|
|African Violets||400 FC (80 µmol)||200 FC (40 µmol)||2-3 hours direct sun is tolerable||1000-1200 FC (200-240 µmol)||https://mrec.ifas.ufl.edu/foliage/folnotes/africanv.htm|
|Aglaonema (Chinese Evergreen, and several species)||200 FC (40 µmol)||100 FC (20 µmol)||1-2 hours direct sun is tolerable||1000-2400 FC (200-480 µmol)||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 (80 µmol)||200 FC (40 µmol)||3-4 hours direct sun is tolerable||3000-7000 FC (600-1400 µmol)||my air plant care video here https://youtu.be/sjNVLgEbvOY||https://bromeliadsocietyhouston.org/genera-intro/tillandsia/|
|Alocasia (several species)||400 FC (80 µmol)||200 FC (40 µmol)||3-4 hours direct sun is tolerable||2000-5000 FC (400-1000 µmol)(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 (80 µmol)||100 FC (20 µmol)||1-2 hours direct sun is tolerable||1500-2000 FC (300-400 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/anthuriu.htm|
|Aspidistra (Cast-Iron Plant)||200 FC (40 µmol)||100 FC (20 µmol)||1-2 hours direct sun is tolerable||2000-5000 FC (400-1000 µmol)||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 (80 µmol)||200 FC (40 µmol)||3-4 hours direct sun is tolerable||5000-6000 FC (1000-1200 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/areca.htm|
|Arrowhead Vine (Syngonium podophyllum)||200 FC (40 µmol)||100 FC (20 µmol)||2-3 hours direct sun is tolerable||1500-3000 FC (300-600 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/nephthyt.htm|
|Begonia (several species)||400 FC (80 µmol)||200 FC (40 µmol)||1-2 hours direct sun is tolerable||2000-2500 FC (400-500 µmol)||https://mrec.ifas.ufl.edu/foliage/folnotes/begonias.htm|
|Bird-Of-Paradise (Strelitzia)||800 FC (160 µmol)||400 FC (80 µmol)||4-5 hours direct sun is tolerable||2000-5000 FC (400-1000 µmol)(estimated based on ‘part shade/part sun’)||http://hort.ufl.edu/database/documents/pdf/shrub_fact_sheets/strrega.pdf|
|Calathea (several species)||400 FC (80 µmol)||200 FC (40 µmol)||1-2 hours direct sun is tolerable||1000-2000 FC (200-400 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/calathea.htm|
|Cordyline (Ti Plant)||400 FC (80 µmol)||200 FC (40 µmol)||3-4 hours direct sun is tolerable||3000 FC (600 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/cordylin.htm|
|Croton (several species)||800 FC (160 µmol)||400 FC (80 µmol)||4-5 hours direct sun is tolerable||3000-5000 FC (600-1000 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/crotons.htm|
|Dieffenbachia (Dumb cane; several species)||400 FC (80 µmol)||100 FC (20 µmol)||3-4 hours direct sun is tolerable||1500-3000 FC (300-600 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/dieffenb.htm|
|Dracaena (several species)||200 FC (40 µmol)||100 FC (20 µmol)||3-4 hours direct sun is tolerable||2000-3000 FC (400-600 µmol)||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 (80 µmol)||200 FC (40 µmol)||2-3 hours direct sun is tolerable||1500-2500 FC (300-500 µmol)||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 (40 µmol)||100 FC (20 µmol)||3-4 hours direct sun is tolerable||1500-2000 FC (300-400 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/waxplant.htm|
|Ferns (Boston Fern, Bird’s Nest Fern, Maidenhair Fern)||200 FC (40 µmol)||100 FC (20 µmol)||Bird’s nest fern/maidenhair fern – 1-2 hours direct sun is tolerable but must keep soil evenly moist||1500-3000 FC (300-600 µmol)||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 (160 µmol)||400 FC (80 µmol)||3-4 hours of direct sun is tolerable||2000-6000 FC (400-1200 µmol)||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 (40 µmol)||100 FC (20 µmol)||1-2 hours direct sun is tolerable but must keep soil evenly moist||1500-2500 FC (300-500 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/fittonia.htm|
|Jade Plant (Crassula ovata, other Crassula)||400 FC (80 µmol)||200 FC (40 µmol)||3-4 hours direct sun is tolerable||5000-6000 FC (1000-1200 µmol)||Book "Tropical Foliage Plants" by Lynn P. Griffith Jr. - https://www.houseplantjournal.com/recommended-product/reference-books/||Jade will stretch with indirect light levels below 200 FC most of the day - it won't die but you may not enjoy the stretched look.|
|Maranta (Prayer Plant)||200 FC (40 µmol)||100 FC (20 µmol)||2-3 hours direct sun is tolerable||1000-2500 FC (200-500 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/maranta.htm|
|Monstera deliciosa||400 FC (80 µmol)||100 FC (20 µmol)||2-3 hours direct sun is tolerable||1000-2500 FC (200-500 µmol) (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 (80 µmol)||200 FC (40 µmol)||2-3 hours direct sun is tolerable||5000-6000 FC (1000-1200 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/norfolk.htm|
|Parlour Palm (Chamaedorea)||400 FC (80 µmol)||100 FC (20 µmol)||1-2 hours direct sun is tolerable||1500-3000 FC (300-600 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/chamaed.htm|
|Peace Lily (Spathiphyllum)||200 FC (40 µmol)||100 FC (20 µmol)||1-2 hours direct sun is tolerable||1500-2500 FC (300-500 µmol)||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 (40 µmol)||100 FC (20 µmol)||2-3 hours direct sun is tolerable||1500-3500 FC (300-700 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/pep.htm|
|Phalaenopsis (Moth Orchid)||400 FC (80 µmol)||200 FC (40 µmol)||2-3 hours direct sun is tolerable||1000-1500 FC (200-300 µmol)||http://www.aos.org/AOS/media/Content-Images/PDFs/GrowingtheBestPhalsPart_3.pdf|
|Philodendron Vines (Heart-leaf, Brasil, etc)||200 FC (40 µmol)||100 FC (20 µmol)||2-3 hours direct sun is tolerable but leaves may lose color.||1500-3000 FC (300-600 µmol)||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 (80 µmol)||200 FC (40 µmol)||2-3 hours direct sun is tolerable||1500-2500 FC (300-500 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/philo-sh.htm|
|Pilea (Aluminum plant, cadierei and others; NOTE: Pilea peperomioides not specifically mentioned)||400 FC (80 µmol)||200 FC (40 µmol)||2-3 hours direct sun is tolerable||1000-2000 FC (200-400 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/pilea.htm|
|Polka Dot Plant (Hypoestes)||400 FC (80 µmol)||200 FC (40 µmol)||2-3 hours direct sun is tolerable||3000-3500 FC (600-700 µmol)||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 (40 µmol)||100 FC (20 µmol)||3-4 hours direct sun is tolerable||3000-5000 FC (600-1000 µmol)||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 (40 µmol)||100 FC (20 µmol)||5-6 hours direct sun is tolerable||1000-6000 FC (200-1200 µmol)||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 (40 µmol)||100 FC (20 µmol)||2-3 hours direct sun is tolerable||5000-7000 FC (1000-1400 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/scheffle.htm|
|Schlumbergera/Rhipsalidopsis (Christmas/Thanksgiving/Easter Cactus)||400 FC (80 µmol)||200 FC (40 µmol)||3-4 hours direct sun is tolerable||1500-3000 FC (300-600 µmol)||https://www.plantgrower.org/uploads/6/5/5/4/65545169/holiday_cactus_production_guide.pdf|
|Spider Plant (Chlorophytum)||400 FC (80 µmol)||200 FC (40 µmol)||2-3 hours direct sun is tolerable||1000-2500 FC (200-500 µmol)||https://mrec.ifas.ufl.edu/Foliage/folnotes/spider.htm|
|Staghorn Fern (Platycerium)||400 FC (80 µmol)||200 FC (40 µmol)||3-4 hours direct sun is tolerable||1000-2000 FC (200-400 µmol)||my staghorn fern care video here: https://youtu.be/bTM3WLwfq78||http://edis.ifas.ufl.edu/mg015|
|Succulents (Aloe, Echeveria, Euphorbia, etc.)||800 FC (160 µmol)||400 FC (80 µmol)||5-6 hours direct sun is tolerable||5000 FC (1000 µmol)||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 (160 µmol)||400 FC (80 µmol)||3-4 hours direct sun is tolerable||6000-7000 FC (1200-1400 µmol)||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 (40 µmol)||100 FC (20 µmol)||3-4 hours direct sun is tolerable||1000-2000 FC (200-400 µmol)||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|
Hi! thanks for the super useful info, already bought a light meter to get into this game 🙂 I can’t understand one thing from the table and the comments: how many hours of given FC levels plants need? Now many hours is this table calculated for?
we have a dracaena reflexa Anita houseplant in a dark corner of our apartment. During winter, this corner gets even darker. As we noticed that the plants starts to lose leaves, we got ourselves a LED lamp on a stand around 20 cm above the dracaena, to see if this would improve things. The lamp has 30 W and around 2900 lumen at 6500 K. Could this lamp be too bright? We’ve noticed that some of the leaves are getting brown/yellow-discolorations, but we aren’t sure if this is due to the lamp or because we kept the plant so long in darkness before getting the lamp (3-4 days ago). What do you think? Is it possible to burn a plant with articial light? Also: We are using the lamp 10 hours / day. Would this be too long as well? Are there any studies on length and intensity of led illumination for different plant types?
I appreciate your effort. You are creative in your work
What is the meaning of the symbol FC What does it represent. And what is the basis of the word if it is an abbreviation of a sentence
FC = foot-candles
This is very useful information for people who wants to really understand how to care for plants. Thanks much for the links provided. Best information I was looking for! This makes is easier to understand my plant needs.
I came across your channel on YouTube and I need some guidance. Should we be measuring indoor artificial lights with PAR or LUM to get the best light for the plants during FALL/WINTER? I am reading on stuff about LUMENS at that LUMENS are measured for human eyes and not plant photosynthesis because it does not contain enough amount of red or blue. Please correct me on this. And if I were to measure the FC, how would you measure it for low/medium/high indirect light?
Hi Richard – I’ll probably need to make a video on this but for now, I’ll try to give you some clarity here:
– PAR is measuring all light between 400-700 nm with equal sensitivity.
– Illuminance is measuring all light between 400-700 nm with highest sensitivity near 560 nm (green) and falling off in a bell-curve shape.
So it’s not quite correct to say that illuminance “does not contain enough red/blue” – illuminance is about what wavelengths the measure is sensitive to, it doesn’t contain anything.
The real implication is illuminance measurement may not reflect “strong or weak” ***if the measured light contains very high blue or red.***
But here’s why you don’t need to worry about this: WHITE light, such as natural light or white LED light, will have a generally balanced spectral distribution of blue, green, and red, so a higher reading of foot-candles/lux will also be a higher reading of PPFD. Basically, illuminance and PAR are *correlated* as long as the spectrum is relatively balanced (which means, the light is mostly white).
The only situation where you will run into a major discrepancy is with purely blue and red light. Your illuminance value will be very low but a PPFD reading will be high. But since there is no real benefit to using purely red/blue light compared to white light, this is of no practical concern.
As for correlating FC reading to low/medium/high indirect light? I don’t. If you look at the “Commercial Light Levels” column, there’s nothing below 1000 FC, which means *ALL* houseplants will grow extremely well if you can get indirect light levels to be as close to 1000 FC as possible. Realistically, they’ll grow nicely in the 400-800 FC range, acceptable in the 200-400 FC range, and just survive if it never gets higher than 200 FC: that’s my take if you’re looking for my version of broad categorizations. High, medium, low are meaningless.
Hope this helps!
Thank you so much for constructing this. It’s been an amazing resource as I’ve started getting into growing and collecting some pretty plants.
I’ve recently acquired a musa ae-ae. Any lighting tips for that one? TIA
Hi everyone, I’m really impressed by the useful information here which are illustrated in simple ways so everyone even inexperienced person can understand.
My name us Dr.Raghda Ramadan, I’m specialized in overcoming indoor air pollutants using green plants, specially in closed workplaces where we spend more than 8 hours daily leading to many side effects of being unattached to nature.
I wish we can cooperate in some workshops coz I’m very willing to encourage people grow green plants in their spaces either home or work .
Darryl, I love your book, and this list is so helpful. Any idea of the light requirements (specifically how many hours of direct sunlight tolerated) for tradescantia zebrina?
Have made some adjustments of various plant locations after reading your book, and am seriously considering getting a light metre to makes sure all my plants are getting what they need. Thanks for sharing your learning!
Thanks, Kelly! T. zebrina grows well in “shade” outdoors, which means up to 3 hours of direct sun is fine – remember that the gardening definition of “shade” does NOT mean complete absence of direct sun, it means less than 3 hours of exposure time. If you’re growing this plant indoors, just put it in your biggest *and* sunniest window.
This is a great source! Thanks, Darryl!
[…] Here’s my list of common houseplants and their light requirements – WITH NUMBERS! […]
Darryl this table is amazing 😍 thank you so much for doing this 🙌!! I’d love to see a new column with the average amount of hours per day needed to achieve that Good Growth.
As a product manager getting into houseplants, I love this! Read your book too and it’s the best houseplant book I’ve read so far.
Thanks, Emma! Glad you found it helpful!
How many hours in a day does a Ficus (I recently got a large rubber plant) need at least 400 fc to keep up maintenance? Likewise, how many hours in a day does it need 800 fc for good growth?
Hi Claire! I’d say roughly 8 hours.
What is the minimum time the plants (moth orchids) need to spend in the light for it to be considered enough… have only limited shelf at the window and might have to start rotation thing … also can’t leave it open whilst the orchids are there as I am worried that the draft will kill them .
The range of light intensity/duration varies a lot. If you want orchids to flower around once year, I’d say they need to be exposed to at least 200-400 FC for at least 6 hours a day. An hour or two of direct sun would be great as well. That’s going to be as close to your biggest window as possible. As for the draft – if there is one, you should have it fixed for the sake of your heating/cooling bill.
Just wanted to say thanks for putting together this resource. Similar to one of the comments above, I ended up using this list frequently and created a sortable table for it – feel free to use it if it’s helpful 🙂
When I originally commented I clicked the “Notify me when new comments are added” checkbox and now each time a
comment is added I get four e-mails with the
same comment. Is there any way you can remove me from that service?
We’re very sorry for the emails! We only recently had our website re-done and so we’re still figuring out the issues.
Is there any link within the email that says “unsubscribe”?
When I look on the commenting part of the page, I don’t see a checkbox that says “Notify me when new comments are added.” but rather, only one that says “Save my name, email, and website in this browser for the next time I comment.” – was that the one you checked?
Please let us know. We’ll do our best to help!
I have referred back to this list SO many times I’ve considered turning it into a sortable list by light levels. Please keep adding to it *begs sweetly* !!
Muito bom, estas informações irão contribuir muito para as minhas pesquisas!
Very informative, thank you! ♥
This is some very nice information and I happen to have some cheap chinese light meter, hopefully it gives me at least some idea of the light levels I have. But I was just wondering how long do the light levels have to be above or within those light levels? I mean how many hours in a day is enough of say, 100 FC to achieve minimal growth? That’s something I didn’t quite understand.