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Normally I grow my Nepenthes outdoors, but winters here are a bit too cold for the lowland species (Zone 9a). Last year, I tried putting them on a shelf by a windowsill (no supplemental lighting) and kept them in trays, but some of them did not make it through the winter. I've decided to get some grow lights to overwinter my lowland Neps this year, especially since I have more now and I'm sure that some of the ultralowlanders (i.e. bical) will not survive on a windowsill. N. gracilis, mirabilis, and maybe some of the small seed-grown species can do okay next to the window for sure, as they did fine last year.

My planned setup is to have 2 trays of lowland Neps on a plant rack with some eggcrate diffuser lining the bottom of each tray. Each tray would be illuminated by 4 bulbs. The plant rack will be in my living room, so it will be ambient humidity (which is not super high). I'm not sure how much the water in the tray will boost humidity, but I can also put a large plastic over the entire set up (and purchase a small fan as well to increase airflow).

Right now the main options I'm looking at are T5s and T8s (2 ft, 4 bulb). T5s would run about $80 for a 4-bulb fixture with bulbs included, while T8s vary from $14 for a cheap 2 ft 2 bulb fixture to $60ish for a 2 ft 4 bulb fixture. I know that T5s are supposed to give off less heat, but since I'm growing lowland Neps, wouldn't more heat be better? I don't plan on adding any extra heat to the plant rack beyond the temperature of my apartment (~65-75 in the winter) and any additional heat from the bulbs. I'm thinking of running the lights 14 hours on/10 hours off; this is based off of what I read about the 'standard' light schedule being 16 on/8 off but that they need less light in winter.

Based on this, would you suggest T5s or T8s? T8s are definitely cheaper and should give off more heat from what I've read (which is good), but T5s should provide stronger light. With fall just around the corner, I'm planning on getting the lights soon before temps drop below 60F outside. The lights would only be used when it's too cold outside, so probably from late October/early November until mid March or so, after which all plants would go back outside. Any feedback would be appreciated.
 
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As I understand it, bicals can be adjusted to windowsill growing though it's certainly not the easiest plant to do so with. I have no experience myself since I have yet to obtain one, unfortunately.

Are you sure the plants that didn't make it were due to low light levels? I would think that low temperatures would be a more likely cause. As for the light types: I believe that T5's and T8's run at roughly the same efficiency (T5's are probably a little higher,) but T5's can handle twice the power so they will put off more light and heat in general, but more or less the same amount of heat per lumen. It all depends on how much light you need.
 
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As I understand it, bicals can be adjusted to windowsill growing though it's certainly not the easiest plant to do so with. I have no experience myself since I have yet to obtain one, unfortunately.

Are you sure the plants that didn't make it were due to low light levels? I would think that low temperatures would be a more likely cause. As for the light types: I believe that T5's and T8's run at roughly the same efficiency (T5's are probably a little higher,) but T5's can handle twice the power so they will put off more light and heat in general, but more or less the same amount of heat per lumen. It all depends on how much light you need.

It may have been low light or low temperatures or a combination of both. The temperature next to the window was around 60F at the coldest, despite the AC being set higher. Both of my amps perished in those conditions, as did a raff. Bicals might be able to adjust to a windowsill, but if the relatively 'easier' species couldn't make it, I wouldn't expect bical to.
 
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I know that T5s are supposed to give off less heat, but since I'm growing lowland Neps, wouldn't more heat be better?

What is this based on? Electric power get converted to light or heat. So higher efficiency light gives more light and less heat than lower efficiency light. If you are talking about T5 normal output, then it has higher efficiency, so you are correct. But if you are talking about T5HO (high output), then the efficiency is pretty similar to T8. In lower temp, T8 has slightly higher efficiency than T5HO in general, and T5HO is slightly higher in warmer temp. So if you compare 1 bulb of T5HO vs 2 bulbs of T8 (to make the amount of light similar to each other), the heat production is similar. Now, there are some ballast related efficiency. Some cheap T8 fixtures may be using cheap, less efficient ballasts.

This is the story when you have some enclosure to capture the heat. In a wide open room, this will not raise a lot of temperature (unless you have lots of them). But if you limit the heat radiated toward the plants from the light bulbs, we feel T5HO might give a bit more "dense" heat. But if you adjust the amount of light (density), it should be similar since the emission spectra is similar between typical T8 an T5HO.
 
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Joined
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T5HOs run hot, they give off the more heat than any other fluorescent tube I own. My T8s are practically cool to the touch compared to my T5HO fixtures.
 
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That's only because the tubes handle twice the power in a smaller form factor. The actual amount of heat produced per lumen is not really any different.
 
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It shouldn't matter unless you can't physically fit enough T8's into a space to provide the required light level. For the same amount of light, you will get the same amount of heat no matter which type of bulb you use. People often equate T5 bulbs feeling hot to the touch with them producing more heat, but it's simply a side-effect of the bulbs being more powerful. A general rule is 2x T8 = 1x T5HO, both for light output and heat output.
 
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What is this based on? Electric power get converted to light or heat. So higher efficiency light gives more light and less heat than lower efficiency light. If you are talking about T5 normal output, then it has higher efficiency, so you are correct. But if you are talking about T5HO (high output), then the efficiency is pretty similar to T8. In lower temp, T8 has slightly higher efficiency than T5HO in general, and T5HO is slightly higher in warmer temp. So if you compare 1 bulb of T5HO vs 2 bulbs of T8 (to make the amount of light similar to each other), the heat production is similar. Now, there are some ballast related efficiency. Some cheap T8 fixtures may be using cheap, less efficient ballasts.

This is the story when you have some enclosure to capture the heat. In a wide open room, this will not raise a lot of temperature (unless you have lots of them). But if you limit the heat radiated toward the plants from the light bulbs, we feel T5HO might give a bit more "dense" heat. But if you adjust the amount of light (density), it should be similar since the emission spectra is similar between typical T8 an T5HO.

I read this somewhere online, so it may or may not be true. The lights I'm looking at are T5HO - I forgot that they were high-output.
When you say 'limit the heat radiated towards the plants', are you referring to using a reflector/reflective material?
 
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I'm in the same zone as you and kept my Amps and Bical in a 20G low covered aquarium on a window sill in my bathroom. All the plants pitchered and were healthy. Now I keep them in a greenhouse, but the aquarium worked well. If it looked too wet, I would just crack the lid for a few days.
 
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I read this somewhere online, so it may or may not be true. The lights I'm looking at are T5HO - I forgot that they were high-output.
When you say 'limit the heat radiated towards the plants', are you referring to using a reflector/reflective material?

It doesn't have to be related to the reflector. Some portion of the energy in electricity gets converted to the light, and the rest of energy is "wasted" as heat. This loss could occur in the ballast or in the tubes. Then the heat get dispersed by conduction (e.g. from inside of ballast to the metal surface of the fixture), convection (from heated metal fixture or light bulb to the surrounding air), or radiation (emitted as electromagnetic wave like Infrared light). When I said "limit", I was talking about the radiation part, not convection part.

When you put the hand close to the light, you can feel the heat. Basically, in some light, heat is emitted (e.g. as infra-red light). To be honest, I don't completely understand why IR becomes heat even though blue photons have more energy (maybe someone can explain it?). People say that HPS throws a lot of heat, and this is the reason. Here is an example of HPS emission, and you notice a peak between 800-850nm: http://customledsystems.com/wp-content/uploads/2013/08/wavelength.png Fluorescent light doesn't have lots of IR, but it does emit some heat. So the amount of heat "thrown" toward plants depends on the emission spectra. Since the emission spectra aren't so different between T5HO and T8, this part shouldn't be so different.

Sorry this is too much details, and probably derailing the discussion. I'm basically saying the same thing as nimbulan who stated it in a much simpler way!
 
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