How Much Light Do Carnivorous Plants Need? – Part 2
In Part 1, we talked about what type of light carnivorous plants need, but what about how much light they need? In the context of helping us make better decisions for our grow setups, this question is really three questions:
Let’s start with the first question by laying out some definitions. Don’t worry about actual numbers yet, we’ll get to those. Just focus on the concepts for now.
Understanding light quantity
Photon – A photon is a single particle of light and therefore the smallest unit of measuring it (Source). Plants absorb photon energy to conduct photosynthesis. Since plants use photons rather than brightness (lumens and lux), our goal from here on out is to quantify all measurements of light in terms of photons. This will include conversions from lumens, lux, and watts.
Micromole (abbreviated μm or μMole) – Since photons are so small, listing an actual photon count for plant lighting would result in astronomical numbers. To help simplify things, we refer to them in micromoles of photons instead, or just micromoles (μm or μMole). 1 μMole consists of 602 QUADRILLION photons (Source).
Photosynthetic Photon Flux (abbreviated PPF or µMol/S) – PPF is the number of µMoles produced by a light source per second within the PAR range of 400-700 nanometers (Source). Think of this like the shower setting on a garden hose. If you squeeze the handle for 1 second, a certain number of water drops will spray out. The PPF is somewhat helpful to know, but nobody turns on a grow light for only 1 second and since light spreads out the farther it gets from the source (becomes dimmer), it doesn’t tell us anything about how many µMoles are actually hitting our plants. Hmm, sounds like we still need more information.
Note: Sometimes light manufacturers will provide the PPF of a grow light but there can be some inconsistencies of how it is measured.
Photosynthetic Photon Flux Density (abbreviated PPFD or µMol/M2 S) – PPFD is the number of µMoles produced by a light source per second over a square meter within the PAR range of 400-700 nanometers (Source). This is the same as PPF but now we’re adding in an area over which the PPF is spread out, or the density of the photons in a given area. This is the idea behind the Inverse Square Law. Again, think of this like the shower setting on a garden hose only now you’ve marked out a square meter on the floor. After squeezing for one second, how many drops of water fall within the square meter?
Knowing the PPFD is very helpful because not only does it tell us how many photons are hitting a given area, but it also means there’s a distance associated with it. Now we’re getting somewhere! Still though, nobody turns on a grow light for only one second and that’s where Moles/Day comes in.
Moles/Day – The number of µMol/M2 S (PPFD) produced over a 24 hour period. It is the daily accumulation of photons over a square meter. Time to pull out the garden hose again. Now, instead of squeezing the handle for one second, keep squeezing it for several hours over a square meter bucket (better have good drainage because that’s a lot of water). The longer you squeeze, the more water drops will collect in the bucket. It could also be said the higher the water pressure (the stronger the light), the faster the bucket will fill up.
Quite a few µMoles can be produced in a 24 hour period, so to make it a more manageable number, we convert it to Moles/Day. There are 1 million µMoles in a Mole.
Knowing the Moles/Day a light produces is the ultimate goal because then we can compare it with the known needs of certain types of carnivorous plants. See where we’re going with this?
Moles/Day (a.k.a. the ball pit)
The Moles/Day needed by carnivorous plants
To estimate the Moles/Day needed by different types of carnivorous plants, we referred to data in this document from Purdue University for plants with similar light requirements. The Moles/Day required by a plant is known as its Daily Light Integral (DLI). The updated table below provides an overall breakdown by genus but the numbers can vary somewhat from one species to the next.
Note: Toward the end of June on a clear day in the United States, the sun emits 40-60 Moles/Day depending on the exact location. These numbers fall in winter as the days become shorter.
Note: In addition to Moles/Day, it is important for many plants to receive 14-16 hours of uninterrupted light during the active growing season. Plants fall into one of three categories; long-day, short-day, or day-neutral where the length of time in light and darkness, despite the Moles/Day, can determine whether a plant goes dormant or not (day-neutral plants are unaffected). Short-day and long-day plants that receive 10-12 hour of light respectively will begin to transition into dormancy. This is called Photoperiodism.
What about Lumens and Lux?
As with Kelvin and CRI, the problem with using lumens and lux to measure light is that they are based on human perception. Humans perceive light in the yellow/green part of the spectrum as brightest. However, light in the blue and red ranges appears much dimmer. This means that while a bulb with a high lumen or lux value may appear intense, it could actually have very little usable light for plants. It all depends on the Spectral Distribution Curve (SDC) of the bulb. Lumens and lux can provide some useful information though and are still widely used, so we’ll take a look at them here and how to convert them to PPF and PPFD later on.
Lumen (lm, a.k.a luminous flux, or just flux)– A measurement of the brightness of a light as perceived by the human eye in a given angle or beam. Lumens are also known as foot-candles when they are measured within a given area and distance. The brightness of a candle 1 foot away from the source within a 1 square foot area (1 foot-candle) is equal to 1 lumen (Source).
Lux (lx)– Lux is the same idea as foot-candles but uses the metric system instead. It is the brightness of a light as perceived by the human eye that falls on a 1 square meter object 1 meter away. 1 lumen spread over 1 square meter equals 1 lux. The same 1 lumen spread over 1 square foot (foot-candle) equals a little over 10 lux because the same amount of light is concentrated in a smaller area (Source). Again, this brings us back to the Inverse Square Law.
If you remember from earlier, PPFD also measures light in a square meters at a given distance. This makes lux which measures brightness our closest equivalent to PPFD which measures photons.
Now let’s start applying all this with some numbers
Let’s say we want to grow Venus Flytraps which have an optimal DLI of 22-34+ Moles/Day. First, we need to hunt down a potential grow light and then make some calculations based on the data provided by the manufacturer.
Great! Most of the work is already done for you. If the manufacturer provides the PPFD, it’s important they also provide three things to help interpret the number:
The distance from the light the PPFD measurement was taken (sets of PPFD measurements at varying distances are better).
PPFD measurements at various points across the illumination footprint to show average intensity, hotspots, and limitations.
The PPFD measurements in context of a Spectral Distribution Curve. A light with a broad-spectrum curve will have a more accurate PPFD than a light with narrow ranges of color. You can read more about why this is the case here.
After evaluating the PPFD value(s) and averaging if needed, all that needs calculated is how long the light must be on (Moles/Day) at a given distance to meet the DLI of our carnivorous plant. Here’s the equation and calculator to do that.
Even after buying a light, it’s a good idea to test the PPFD for your particular setup rather than relying solely on the manufacturer’s claim. A quantum PAR meter can help.
If the manufacturer only provides lumens, we’ll need to calculate the overall area the bulb or fixture will light up at a given height. Then, convert the lumens into lux and PPFD before finally calculating the Moles/Day. To do this we need to know a few things:
The brightness of the light at its source (total lumens).
The type of light such as an incandescent or fluorescent bulb.
The angle the light is focused from the fixture (usually achieved with some type of reflector).
Our potential or preferred light height.
The length of the light fixture (if applicable).
Note: The following section breaks down each step with a separate equation and calculator. If you’d rather do everything at once, use this calculator instead.
Figure out the area lit by using the height of the light and angle of the reflector or beam.
Divide the total lumens by the calculated surface area to get the Lux.
Convert Lux to PPFD. This is tricky since lux measures brightness as perceived by the human eye rather than actual photons. Without fully evaluating the Spectral Distribution Curve (SDC) of a light, a direct method of conversion isn’t possible. However, certain types of lights tend to have similar SDCs so we can use this to help us estimate for the rest. The conversion factors used here are based off values provided by Apogee Instruments, Environmental Growth Chambers, and Sylvania.
Convert the PPFD to Moles/Day. If we multiply the PPFD by the number of seconds the light will be on each day and then convert it to Moles, we will have the Moles/Day produced by the light.
Do the resulting Moles/Day come close to the DLI needs of our carnivorous plant? If they do, then job well done! If the Moles/Day are too high or too low, try making some adjustments to get closer to the target DLI.
Also remember, these calculations will provide the PPFD and Moles/Day across the entire area defined by the beam or reflector angle. Real world values will be higher towards the center of the space and lower towards the edges. The calculations also assume no light escapes outside the defined area due to inefficient reflectors. Think of this as an estimate of the PPFD and total Moles/Day to help get you in the ballpark. Then once the space is set up, see how your plants are responding or test the numbers with a quantum PAR meter and make further adjustments.
Please note: We are talking about consumed watts which are provided for most standard bulbs. We are not talking about PAR watts (a.k.a irradiance or W/m2) which is yet another way for measuring lighting. We have found manufacturers provide PAR watts less frequently than the other measurements already discussed or if they do, it is alongside PPFD outputs. Therefore, PAR watts will not be covered in this article. However, if you need the conversions, they can be found here.
If the only detail a manufacturer provides is a wattage rating, we highly recommend looking at other grow light options. Determining whether a light is suitable based on watts alone is the least reliable of the methods outlined here. This is because the estimate is based on consumed energy rather than emitted energy. Furthermore, this efficiency can vary a great deal depending on the hardware, bulb type and Spectral Distribution Curve.
Nonetheless, we’ll lay out one possibility for estimating the amount of light produced, but take it with a grain of salt. To start, let’s look at a couple more terms:
Watt (W) – Energy itself is measured in joules (J). A watt is a joule of energy over the course of 1 second (Source).
The number of watts a light consumes will always be more than the number of watts converted to light. This is because some of the energy will be turned into heat and lost to inefficiencies of the bulb/fixture. Certain types of technology convert watts to light more efficiently than others. For example, LEDs can use fewer watts than incandescent bulbs while producing more light. The rate at which a bulb converts wattage to usable light for plants (photons in the PAR range) is called it’s Photosynthetic Photon Efficacy.
Photosynthetic Photon Efficacy (PPE)– The number of µMol/s (PPF) within the PAR range of 400-700 nm a light produces per watt of energy consumed (Source).
Ok, back to the calculations. If a manufacture only provides watts, multiply the total wattage by the known PPE of similar types of lights to get a rough idea of the PPF. Then, calculate the overall area the bulb or fixture will cover at a given height and beam angle. After this, divide the PPF by the coverage area before converting it to PPFD and Moles/Day. To summarize, here are the things needed:
The energy consumed by the fixture (total actual wattage).
The angle the light is focused from the fixture (usually achieved with some type of reflector).
The potential or preferred light height.
The length of the light fixture (if applicable).
Note: The following section breaks down each step with a separate equation and calculator. If you’d rather do everything at once, use this calculator instead.
Estimate the number of µMol/s (PPF) produces by multiplying the total wattage with the PPE of similar lights. The conversions used for this can be found here and here along with how they were measured and which specific lights were used in the tests.
Figure out the area lit by using the height of the light and angle of the reflector or beam.
Divide the total PPF by the calculated surface area to get the PPFD.
Convert the PPFD to Moles/Day. If we multiply the PPFD by the number of seconds it will be on per day and then convert that number to Moles, we will have the Moles/Day produced by the light.
Do the resulting Moles/Day come close to the DLI needs or our carnivorous plant? If they are too high or too low, try making some adjustments to the setup to get closer to the target DLI.
As stated previously, using wattage to estimate light availability for plants is less than ideal for many reasons. It may get you headed in the right general direction, but considering another grow light that gives more information or testing the numbers with a quantum PAR meter once the light is set up is advisable.
Some other considerations
Bulb life and degradation
Consider the life of a bulb and the rate it degrades before investing in a grow light. Replacement costs can add up fast if a bulb has a short life span. A bulb that degrades quickly and no longer produces intended light levels will eventually impact a plant’s health. Here are some resources available on this subject for various types of bulbs:
Heat from a light may be good or bad depending on the plant and should be taken into account when designing a grow space. Drosera from the Petiolaris Complex like lots of heat. Heliamphora and Darlingtonia on the other handneed cool conditions.
Lights typically run hotter or cooler depending on the type of technology. Incandescent bulbs produce a lot of heat while LEDs produce less. Many fluorescent lights tend to be somewhere in the middle. In addition to the type of light, other factors including ballast placement, heat sinks, and reflector design can influence the rate of heat dissipation.
Reflectors
Grow light reflectors are important for several reasons. The main one being that they help redirect light down onto plants from the sides and back of a bulb. They also help spread light as evenly as possible across the footprint of the grow space.
Reflector can have either a specular (smooth) finish or diffuse (hammered) finish. Specular reflectors may be more efficient at reflecting light into the grow space. However, they can create uneven hotspots in the footprint. In contrast, diffuse reflectors spread light more evenly but may bounce a portion of it away from the plants. To reduce light being wasted outside of the grow space, additional reflective materials such as Mylar can be positioned vertically around the perimeter.
Next steps
We know this is a lot to take in. We’ve not only covered how light is quantified for plants and how much light certain types of carnivorous plants need, but also talked about three different ways of converting light measurements. Sometimes the same information said in a different way can help make complex ideas easier to understand. Farmer Tyler’s article on supplemental lighting for plants covers many of these same topics, as does this article from Inda-Gro and this post by edman007 on FlytrapCare Forums.
And finally, let’s look at some grow lights currently available on the market along with specifics about the quality and quantity of light they produce: Part 3 – Which Grow Lights Are Best?
Amazing, Best light guide for carnivorous plants i found on the Internet so far. Thanks a lot!
After searching a while for LEDs for my small terrarium, i think i will go for the Mars hydro ts600. Pretty wide spectrum and enough PPFD for 20-30 cm distance i guess.
Only one more general question:You wrote that you can calculate the amount of time the light needs to be switched on. I Heard that nepenthes need 12-14hours light a day. Would you say its also fine to only turn on the light for 6 hours if you have enoug ppfd to reach the 14 DLI in this time? Or do they prefer to get the DLI distributed over one day?
Thank you Paul! Great question too, 12-14 hours of light is generally a good range for to aim for with Nepenethes. Something we need to add to this article is that 10-12 hours is still the minimum length of time you’ll want to have the light on depending on the plant. Plants fall into one of three categories; long-day, short-day, or day-neutral where the length of time, despite the Moles, can determine whether the plant goes dormant or not (day-neutral plants are unaffected). This is called Photoperiodism and the 10-12 hour marks are typically where the response is induced.
Thanks to the Team for curiousplant for the nice description.
My Comment: a grow light lighting manufacturer should provide a PPF Value not just ppfd.
This is equivalent to the LUMEN-Value. Also in the standard lighting industry LUMEN is used to calculate the efficiancy not LUX!!
The efficacy of a light is calculated using PPF / Watt (Consumption)
PPF [µmol/s]
Consumption [W]
µmol/Ws
one Ws = J (Joule)
Result µmol/J
PPFD is equivalent to LUX.
therefore a single PPFD should never be used for such a calculation.
Taking the average of multiple PPFD reading makes more sense but there is a a lot of space for mistakes and cheating.
PPF can only be measured witha integrated sphere, while PPFD is measured using a “handheld” spectrometer”
Because only lighting laboratories useually have an integrated sphere, most of the “Independent” tests are made with spectrometers°
Hi Jakob, I think you bring up some great points, thanks so much for taking the time to comment!
While PPF is a more equivalent measurement to Lumens, manufacturers seem to provide PPFD more frequently than PPF so we wanted to make sure the calculators were geared toward PPFD entries.
Thank you for pointing out our error in the definition for efficacy! It is corrected.
It is true that an average PPFD would be most equivalent to LUX. However, we felt it would be best to leave it up to the individual grower as to whether they would like to average PPFD numbers or use hotspot and/or weaker readings for the calculations based on their needs. An average PPFD might be better for a larger plant that will take up more of the footprint while individual readings can be more beneficial for smaller plants based on where they will sit under the light.
Newbie VFT Hobbyist
June 4, 2020 at 1:44 pm - Reply
Thank you for this! I am new to this hobby and would really love to get your input. I got 4 of these from China and can’t seem to figure out if it is enough for my VFTs — given these values, how can I determine if this is enough?
Thanks for you question! With these specs, your best option would be to use the lumens calculator since those are the values provided. “Cool White” would be the closest match to the Kelvin temperature listed. Once you have the Moles/day conversion, you can compare this to the DLI (Moles/day) chart for VFTs to see if the lights would be enough. I hope this helps!
your problem is the missing PPF (or at least a ppfd map)
the Luminous Flux of 1800LM is not relevant for plants.
there is no general conversion between Lumen and PPF as this is depending on the light spectrum.
If you know PPF you can calculate PPF / AREA minues losses due to reflection (it is also a big difference if the environment is closed or open). as the angle is 180° a lot of light is going to the side instead towards your cultivation area.
I personally would not buy a light without knowing the PPF (if its for plants ;-) )
Thank you so much for this. I’m new to artificial lights and using this information have been able to turn around my set up. Using the SF-600 and have also got a Sansi 70W.
I’m looking for a way to make a diy reflector for my lights – any ideas?
Hi Jason, I’m glad you found it helpful! Regarding DIY reflectors, Mylar can be an effective and inexpensive option for reflecting light. If you are looking to build a hood or reflector around the lights themselves, I would aim to use something that has a low risk of catching fire or melting like aluminum sheeting. I hope this helps!
I write as a new in the hobby with a doubt of artificial light,
After two weeks of putting my plants under the Arcadia Led 51W (10-20cm) many of them start becoming red.
All Cephalotus (which is great cause in the nature they do it) but also N. Mina, N. Talagensis en Overall N. Burbidgeae.
Plants look great and since this effect hasn’t come to all plants I could think that it’s the genetic of those plants, and that, they show their best.
But on the other hand, it begins looking a little artificial or bizarre. Nepenthes red, you know (being almost all green).
I guess it’s not a symptom of sunburn cause there’s no sun but a artificial light. But is it bad or dangerous? Should I increase distance?
Right know there is between 10k Lux and 20k Lux for all plants, which are the ranges I have always read they must be. (PAR should be somewhere between 300-600). And at the same time, it’s the same quantity as they were in shade conditions in a greenhouse for example. So I could think it’s not dangerous but natural conditions.
Hi Guillermo, it sounds like the light intensity is working great for some of your plants while for others it may be a little too intense. While red leaves on Nepenthes aren’t necessarily a bad thing, it is still possible to burn them with artificial light. The red color could have something to do with the species or genetics like you said, but if it seems like they are becoming unhealthy or if you prefer they looked more green, moving them farther from the light would be a good idea. I hope this helps!
Hi Cristin, the beam angle of your light will be determined and influenced by the fixture and any reflectors that may be attached. Sometimes the angle will be listed in the light’s specs or a rough visual estimation can also work. Thanks!
The light angle is determined by the fixture reflector, not the position of the light relative to you. For example, a plain incandescent light bulb screwed into a lamp without any type of lamp shade or reflector would create an angle of about 360 degrees since the light spreads in all directions. If you were to take that same bulb and screw it into a fixture with a reflector, the angle of the light would be about the same as the shape of the reflector. If the reflector is in the shape of a 90 degree cone, the light angle would also be about 90 degrees since most of the light is now being redirected. Thanks for your question!
Guillermo
February 25, 2020 at 3:54 pm
Thanks!
I’ve just bought Arcadia Jungle Dawn LED Bar and I’ve seen it has 120 degrees of angle.
It also appears the SDC and the KiloLux and PAR depending of the distance. But I don’t know how I must interprete these data.
That’s great! Each KiloLux equals 1000 lux so this could be converted to PPFD using some of the calculators under the section “Manufacturer provides Lumens”. PAR is calculated in relation to Watts of output which our calculators don’t cover as it isn’t used as frequently. Although if you check the section titled “Manufacturer provides Watts”, there is a note about PAR Watts and link with conversions for PAR Watts.
The most reliable way to calculate the DLI for this light would be to contact the manufacturer and see if they have any PPF or PPFD readings available. After gathering these numbers, you should be able to plug them into the calculators here to determine the DLI. If the readings aren’t available, your next best option would be to take your own readings with a PAR meter. Buying a good PAR meter can be expensive but some aquarium stores have them available to borrow or rent. You can also try estimating the DLI using the wattage calculators but this will probably give you the least reliable numbers given the reasons mentioned in the article. I hope this helps!
Amazing, Best light guide for carnivorous plants i found on the Internet so far. Thanks a lot!
After searching a while for LEDs for my small terrarium, i think i will go for the Mars hydro ts600. Pretty wide spectrum and enough PPFD for 20-30 cm distance i guess.
Only one more general question:You wrote that you can calculate the amount of time the light needs to be switched on. I Heard that nepenthes need 12-14hours light a day. Would you say its also fine to only turn on the light for 6 hours if you have enoug ppfd to reach the 14 DLI in this time? Or do they prefer to get the DLI distributed over one day?
Thank you Paul! Great question too, 12-14 hours of light is generally a good range for to aim for with Nepenethes. Something we need to add to this article is that 10-12 hours is still the minimum length of time you’ll want to have the light on depending on the plant. Plants fall into one of three categories; long-day, short-day, or day-neutral where the length of time, despite the Moles, can determine whether the plant goes dormant or not (day-neutral plants are unaffected). This is called Photoperiodism and the 10-12 hour marks are typically where the response is induced.
Thanks to the Team for curiousplant for the nice description.
My Comment: a grow light lighting manufacturer should provide a PPF Value not just ppfd.
This is equivalent to the LUMEN-Value. Also in the standard lighting industry LUMEN is used to calculate the efficiancy not LUX!!
The efficacy of a light is calculated using PPF / Watt (Consumption)
PPF [µmol/s]
Consumption [W]
µmol/Ws
one Ws = J (Joule)
Result µmol/J
PPFD is equivalent to LUX.
therefore a single PPFD should never be used for such a calculation.
Taking the average of multiple PPFD reading makes more sense but there is a a lot of space for mistakes and cheating.
PPF can only be measured witha integrated sphere, while PPFD is measured using a “handheld” spectrometer”
Because only lighting laboratories useually have an integrated sphere, most of the “Independent” tests are made with spectrometers°
Hi Jakob, I think you bring up some great points, thanks so much for taking the time to comment!
While PPF is a more equivalent measurement to Lumens, manufacturers seem to provide PPFD more frequently than PPF so we wanted to make sure the calculators were geared toward PPFD entries.
Thank you for pointing out our error in the definition for efficacy! It is corrected.
It is true that an average PPFD would be most equivalent to LUX. However, we felt it would be best to leave it up to the individual grower as to whether they would like to average PPFD numbers or use hotspot and/or weaker readings for the calculations based on their needs. An average PPFD might be better for a larger plant that will take up more of the footprint while individual readings can be more beneficial for smaller plants based on where they will sit under the light.
Thank you for this! I am new to this hobby and would really love to get your input. I got 4 of these from China and can’t seem to figure out if it is enough for my VFTs — given these values, how can I determine if this is enough?
Plants Grow LED Light T600-LED18W
Size: 60 x 5x 5 cm
Crystalline Ball (RA>80.22-24LM): 96PCS 2835SMD
Colour Index: RA>=80
Luminous Flux: 1800LM
Luminescence Angle: 180
Degree Power: 18W
Colour Temperature: 5000-5500K
Hope you can help!
Thanks for you question! With these specs, your best option would be to use the lumens calculator since those are the values provided. “Cool White” would be the closest match to the Kelvin temperature listed. Once you have the Moles/day conversion, you can compare this to the DLI (Moles/day) chart for VFTs to see if the lights would be enough. I hope this helps!
your problem is the missing PPF (or at least a ppfd map)
the Luminous Flux of 1800LM is not relevant for plants.
there is no general conversion between Lumen and PPF as this is depending on the light spectrum.
If you know PPF you can calculate PPF / AREA minues losses due to reflection (it is also a big difference if the environment is closed or open). as the angle is 180° a lot of light is going to the side instead towards your cultivation area.
I personally would not buy a light without knowing the PPF (if its for plants ;-) )
Thank you so much for this. I’m new to artificial lights and using this information have been able to turn around my set up. Using the SF-600 and have also got a Sansi 70W.
I’m looking for a way to make a diy reflector for my lights – any ideas?
Hi Jason, I’m glad you found it helpful! Regarding DIY reflectors, Mylar can be an effective and inexpensive option for reflecting light. If you are looking to build a hood or reflector around the lights themselves, I would aim to use something that has a low risk of catching fire or melting like aluminum sheeting. I hope this helps!
I write as a new in the hobby with a doubt of artificial light,
After two weeks of putting my plants under the Arcadia Led 51W (10-20cm) many of them start becoming red.
All Cephalotus (which is great cause in the nature they do it) but also N. Mina, N. Talagensis en Overall N. Burbidgeae.
Plants look great and since this effect hasn’t come to all plants I could think that it’s the genetic of those plants, and that, they show their best.
But on the other hand, it begins looking a little artificial or bizarre. Nepenthes red, you know (being almost all green).
I guess it’s not a symptom of sunburn cause there’s no sun but a artificial light. But is it bad or dangerous? Should I increase distance?
Right know there is between 10k Lux and 20k Lux for all plants, which are the ranges I have always read they must be. (PAR should be somewhere between 300-600). And at the same time, it’s the same quantity as they were in shade conditions in a greenhouse for example. So I could think it’s not dangerous but natural conditions.
Thank you very much!
Hi Guillermo, it sounds like the light intensity is working great for some of your plants while for others it may be a little too intense. While red leaves on Nepenthes aren’t necessarily a bad thing, it is still possible to burn them with artificial light. The red color could have something to do with the species or genetics like you said, but if it seems like they are becoming unhealthy or if you prefer they looked more green, moving them farther from the light would be a good idea. I hope this helps!
Argh I so confused. How do you determine angle?
Hi Cristin, the beam angle of your light will be determined and influenced by the fixture and any reflectors that may be attached. Sometimes the angle will be listed in the light’s specs or a rough visual estimation can also work. Thanks!
Let’s say we put light totally vertical up from the plants. Would that be 90 degrees?
Hi Guillermo,
The light angle is determined by the fixture reflector, not the position of the light relative to you. For example, a plain incandescent light bulb screwed into a lamp without any type of lamp shade or reflector would create an angle of about 360 degrees since the light spreads in all directions. If you were to take that same bulb and screw it into a fixture with a reflector, the angle of the light would be about the same as the shape of the reflector. If the reflector is in the shape of a 90 degree cone, the light angle would also be about 90 degrees since most of the light is now being redirected. Thanks for your question!
Thanks!
I’ve just bought Arcadia Jungle Dawn LED Bar and I’ve seen it has 120 degrees of angle.
It also appears the SDC and the KiloLux and PAR depending of the distance. But I don’t know how I must interprete these data.
https://www.arcadiareptile.com/jungledawn-ledbar/
That’s great! Each KiloLux equals 1000 lux so this could be converted to PPFD using some of the calculators under the section “Manufacturer provides Lumens”. PAR is calculated in relation to Watts of output which our calculators don’t cover as it isn’t used as frequently. Although if you check the section titled “Manufacturer provides Watts”, there is a note about PAR Watts and link with conversions for PAR Watts.
HEY, IM FROM MEXICO AND I FOUND THIS SO AMAZING, ITS DIFFICULT SOMETIMES TO FOUND HELPFUL INFORMATION, AND THIS GIVE ME A LOT OF KNOWLEDGE TO APPLY.
Hi Irvin, glad you found it helpful! Thanks : )
~ Elizabeth
Wonderful breakdown!
Thank you, I’m glad you found it helpful!
~ Elizabeth
Hello,
I would like to ask you how to calculate DLI when I use LED COB 50w full spectrum and light source has 25×25 mm?
Thank you in advance.
Greetings,
Rafal
Hi Rafal,
The most reliable way to calculate the DLI for this light would be to contact the manufacturer and see if they have any PPF or PPFD readings available. After gathering these numbers, you should be able to plug them into the calculators here to determine the DLI. If the readings aren’t available, your next best option would be to take your own readings with a PAR meter. Buying a good PAR meter can be expensive but some aquarium stores have them available to borrow or rent. You can also try estimating the DLI using the wattage calculators but this will probably give you the least reliable numbers given the reasons mentioned in the article. I hope this helps!
Thank you,
Elizabeth
Your reply is helpful a lot, thank you.
Rafal