FlytrapCare Carnivorous Plant Forums

Here is a quick notice before you read the rest of this thread:
I hope I do not sound rude but I know that plants grow better in sunlight. I heard it hundreds of times but I can NOT grow my plants outside here. I have VERY limited space (The space I have is occupied by a few other plants) and the climate in South Africa may be very different than yours so what works for you may not work for me.

With that said, feel free to read on

Growing Area Details

I have been growing different plants in a terrarium for a year now. the lights I use are made by me (I bought the drivers, the LEDs, wires, screws, cable ties, heat-sinks, fans and the rest all separately and put them all together by myself.) and as such you will have to trust in the specs I give you.

I grow my plants under the 100W Growlight that I built consisting of 14 Blue (450nm) LEDs at 3 watts each and 22 full spectrum (380-840nm) LEDs also at 3 watts each. My full spectrum lights are NOT white lights, they are these:

http://www.bidorbuy.co.za/item/26162544 ... _Chip.html

Also, here is the link to the blue LEDs I used:

http://www.bidorbuy.co.za/item/26198667 ... 600mA.html

Other notable features of the tank is that it is vented by two fans and has reflective foil on it's sides and back. when I'm not viewing the plants, I put white paper in the front as well so any and all light that doesn't escape or whatever could be reflected back.

Humidity averages at 40 percent (sometimes 90 percent id I turn off the venting fans), temp is 20 at night 28 (Celsius) in the day. All the above values can fluctuate.

Plants and Problems

Here is my problem I need help with: I have been growing my plants in the tank for a year with only the full spectrum LEDs and they grew fine, except for the more light-hungry plants showing symptoms of needing light, but not much. finally, last December I ordered some of the blue LEDs and replaced some of my full spectrum lights with them (I had 36 full spectrums at the time, but replaced 14 of them with the blues) and by heavens the plants colored up like a child's painting! The plants still show signs of needing light, But they now seem to be getting "sunburn" and still wont grow like they should (My sundews and other plants are doing great, save for some "sunburn" too).

The same happened with my Cephalotuses, but as soon as I introduced the blue lights they died back completely. I forced out a place for them outside which seemed to save them. Barely.

My guess is that the blue lights I have on somehow (I think I may have ordered the wrong Blue LEDs actually...) have WAY too much UV light and too little blue light, considering the burns the plants have... right? So I should get true blue LEDs of 460nm instead of "Royal Blue" LEDs who are half UV?

(Sticking a random note in here upon editing: It seems the excess UV may be the problem of why my plants are dying. Some UV is good, but too much UV could kill a plant that has not been hardened/acclimated against it.
I say I have too much UV because my full spectrum lights put out UV too, but in controlled amounts that colored my plants slowly. Suddenly replacing 14 of the LEDs with UV intensive LEDs, thinking they were mainly blue... Its like suddenly putting a plant that grew in the dark in the blazing sun... Or perhaps a gamer like me suddenly deciding to tan... ouch...)

Strangely enough my all green flytraps (and other plants that aren't named specifically) are doing very well... you can probably see one perking up in the picture at the back. (The all green was sick, but once I divided it from 4 new plants it grew great again)

here are pictures of the tank and the plants (Who look really sick) in question and a wavelength range chart I (randomly) thought may be helpful:

........ Erm... I actually think I answered myself, lol

I believe I saw you post this elsewhere and I asked why you used extra blue LEDs but don't recall getting a response. I see my answer in your post here - the light wavelength/effect on plant growth chart. My first advice is to delete that and forget about it.

My best guess as to what's going on is that your plants are simply receiving too much blue light. Blue primarily acts as a growth regulator, while red is more photosynthetically efficient (green is actually more so, but that's another discussion entirely.) Some plants can develop growth abnormalities or refuse to grow at all with too much blue light and I suspect that's what's going on here.

So basically, I think you're just burning your plants with too much light, but they also look like they aren't receiving enough because too much of that light is blue. If you look at commercial red/blue LED fixtures, you'll find they most often use a 3:1 ratio of red to blue LEDs and I would suggest you tune your system the same way.

nimbulan wrote:I believe I saw you post this elsewhere and I asked why you used extra blue LEDs but don't recall getting a response. I see my answer in your post here - the light wavelength/effect on plant growth chart. My first advice is to delete that and forget about it.

My best guess as to what's going on is that your plants are simply receiving too much blue light. Blue primarily acts as a growth regulator, while red is more photosynthetically efficient (green is actually more so, but that's another discussion entirely.) Some plants can develop growth abnormalities or refuse to grow at all with too much blue light and I suspect that's what's going on here.

So basically, I think you're just burning your plants with too much light, but they also look like they aren't receiving enough because too much of that light is blue. If you look at commercial red/blue LED fixtures, you'll find they most often use a 3:1 ratio of red to blue LEDs and I would suggest you tune your system the same way.

Strange though, because a lot of other guys grow their plants under lights that are a LOT stronger than mine (900 actual watts compared to my 100 actual Watts) With much more blue light. I understand what you're trying to say, but I do take your response with a grain of salt. I have never heard of a plant ever getting too much light, unless it is somehow brighter than the sun, which is impractical.

The sun shines at 100 000 Lux at day. my setup shines at 20 000 Lux (last I checked atleast) at 12 inches away from the LEDs.

I do believe what you are saying about red and green light though, because it is true, but green LEDs are very inefficient where as blue LEDs are the most efficient of all colors (or second most efficient).

I need more blue because I actually have way too much red light in my tanks. nearly three times as much as my blue light and my plants are flowering like frikkin CRAZY (a new flower every week for my now darker-than-blood-red pygmies) and it's killing me... and them, lol... But I have a few good reasons to believe that the UV rays in the tank is killing the plants though because of the research I did on UV rays.

The other post you are referring to, though similar, has nothing to do with this, lol. the other post was just a report on my observations. This post is an actual question, and me asking for help, although I will be very critical (And I hope I don't sound rude ) about the info I get.

The growth chart definitely has a few faults on it, I will admit, but it does help a little with the basics, despite missing a lot of crucial points.

In the end, I think I will take some of your advice though and redesign my growlight. I will most likely take off 50 percent of my full spectrum lights, order some good red and blue LEDs and see how they go, thanks to them being.... relatively cheap.

I wish green LEDs were more efficient though... (to the guys who dont know what we are talking about and cringing your teeth out about how green light is useless... DON'T WORRY! Lol It's science, very few people will understand what me and Numbulan mean by what we say about the green light... unless I am underestimating you guys, which can easily happen...)

So anyways, thank you very much for the reply, it really made me think...

Yes you are correct that blue is the most efficient LED color, while green is the least efficient. It's actually more efficient to produce green light by using a blue LED with a phosphor because of this.

I realize you're already invested in this setup, but I would personally recommend just sticking with white LEDs. The red/blue ones will color up the plants the best, but the plants should grow best under white (assuming it's strong enough) since green light can reach more chloroplasts than the other colors can. I personally just recently assembled some LED light bars using some brand new super high efficiency Samsung parts though the jury's still out on how they compare to my previous LEDs (also white, but Cree parts.)

nimbulan wrote:Yes you are correct that blue is the most efficient LED color, while green is the least efficient. It's actually more efficient to produce green light by using a blue LED with a phosphor because of this.

I realize you're already invested in this setup, but I would personally recommend just sticking with white LEDs. The red/blue ones will color up the plants the best, but the plants should grow best under white (assuming it's strong enough) since green light can reach more chloroplasts than the other colors can. I personally just recently assembled some LED light bars using some brand new super high efficiency Samsung parts though the jury's still out on how they compare to my previous LEDs (also white, but Cree parts.)

Err, I don't use white LEDs at all, lol, I posted above what LEDs I use.

I am quite invested in it, you are correct, but it's mostly just for experimentation. Actually, yeah, let me quickly see how plants grow with white LED's (I'm assuming they follow the same rules as fluorescent lights, right? Low kelvin for flowering and high kelvin for growing?) I guess I will find out soon...

Cree..... hmm... I saw those for sale too... I'm curious, what are your results with them, if you have seen any noticible results?

You're a smart guy. I actually haven't had this fun talking about lights in a long time, lol. Thanks for the white light idea, I didnt think about it, since coloring them up is the lowest of my priority, but actually growing them is the top priority...

EDIT: Sorry if I'm, like, not making any sense or am talking in circles... it's... err... well, it's 3 am here

I have seen nothing true about lower kelvin rating inducing flowering and higher kelvin supporting more vegetative growth. I have know idea why "grow light" manufacturers are intent in spreading that myth around either.

I think the flowering/growth spectra idea comes from the idea that the color temperature of sunlight changes depending on the season due to the angle of the sun during the day, so during flowering season the color temperature will be lower....or something like that. In any case I have to say I'm dubious about its accuracy too.

As for my Cree lights, I used a CXB3070 COB LED, which is basically a tightly-clustered array of LEDs about 2cm diameter which can handle upwards of 100W of power. While I've been happy with the output, the cost of building it, and how well plants grow under the brightest spots, it's basically a point-source light and this causes two significant problems. Firstly, the light it casts over a grow area is very uneven so it's far brighter in the middle than near the edges. Secondly it casts pretty strong shadows, so I have to be careful where I put taller plants and pot tags and some leaves on plants just aren't going to get much light. Cooling can also be an issue since these COBs do dissipate a lot of heat in a very small area.

While the efficiency is comparable between that and my new strip lights, I find the strip lights provide much more even lighting, similar to fluorescent fixtures. The jury's still out on how the plants respond as I've only had them up for a week and a half so far.

Benurmanii wrote:I have seen nothing true about lower kelvin rating inducing flowering and higher kelvin supporting more vegetative growth. I have know idea why "grow light" manufacturers are intent in spreading that myth around either.

I guess you have a very decent point there, lol.

nimbulan wrote:I think the flowering/growth spectra idea comes from the idea that the color temperature of sunlight changes depending on the season due to the angle of the sun during the day, so during flowering season the color temperature will be lower....or something like that. In any case I have to say I'm dubious about its accuracy too.

As for my Cree lights, I used a CXB3070 COB LED, which is basically a tightly-clustered array of LEDs about 2cm diameter which can handle upwards of 100W of power. While I've been happy with the output, the cost of building it, and how well plants grow under the brightest spots, it's basically a point-source light and this causes two significant problems. Firstly, the light it casts over a grow area is very uneven so it's far brighter in the middle than near the edges. Secondly it casts pretty strong shadows, so I have to be careful where I put taller plants and pot tags and some leaves on plants just aren't going to get much light. Cooling can also be an issue since these COBs do dissipate a lot of heat in a very small area.

While the efficiency is comparable between that and my new strip lights, I find the strip lights provide much more even lighting, similar to fluorescent fixtures. The jury's still out on how the plants respond as I've only had them up for a week and a half so far.

Ah, I see what you mean, and I understand completely. what color temperature were they though?

I chose 4000k for my COB LEDs and was going to do the same again, but Digikey was out of stock for 4000k 2' strips so I went with 3500k. Oddly, though the strips are rated at higher CRI than my Cree chips, the color rendition seems visually worse (not that the plants care about this.)

nimbulan wrote:I chose 4000k for my COB LEDs and was going to do the same again, but Digikey was out of stock for 4000k 2' strips so I went with 3500k. Oddly, though the strips are rated at higher CRI than my Cree chips, the color rendition seems visually worse (not that the plants care about this.)

So growing them under a 3500k is just fine too? bacause I can only find 3500k and 6500k diodes at my store and thought about buying 10 of each.

Upon some research, I found that red light seems to make plants grow longer, higher (one of the types of growth red light gives anyways) and blue simply thickens the plant. I may be very wrong though, since thickening happens with other spectrums too, as well as the elongation...

I'm saying those because I see that 3500k has more red than blue and 6500k has more blue than red.... right?

EDIT: I stand corrected.... My supplier actually does have 4000k Diodes too

It's not that red causes the plant to grow etiolated, it's that blue light suppresses that growth habit. I think that's the main reason why high color temperatures are recommended for vegetative growth (to prevent etiolation) and low color temperatures for flowering (more energy for the plant!) It ends up being a bit of a balance between growth regulation and optimal photosynthesis.

nimbulan wrote:It's not that red causes the plant to grow etiolated, it's that blue light suppresses that growth habit. I think that's the main reason why high color temperatures are recommended for vegetative growth (to prevent etiolation) and low color temperatures for flowering (more energy for the plant!) It ends up being a bit of a balance between growth regulation and optimal photosynthesis.

Ah, I see... So... That could be why my plants are doing so poorly then... Is that why you said I had too much blue light? Because I am starting to see why I would need more red light instead...

Ok, so in theory to make sure I understand, if a flytrap were to be grown in 2 different conditions, (3000-4000k vs 6500k) The one under the 6500k would be low growing and wide leaved while the the one under the 3000-4000k light would be perky and with thinner petioles, right?

I wouldn't say it would be low growing - generally the low/upright growing is determined by the dormancy cycle (or sometimes genetics.) That said I'm not entirely sure how flytraps would respond, though they may grow just fine under either color temperature.

nimbulan wrote:I wouldn't say it would be low growing - generally the low/upright growing is determined by the dormancy cycle (or sometimes genetics.) That said I'm not entirely sure how flytraps would respond, though they may grow just fine under either color temperature.

Ah, I see. ah well, we'll see what happens. Thanks for your help