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What's the maximum effective distance for Neps under T5s?

seedjar

seedjar

Let's positive thinking!
I've been very pleased with switching to T5HO lights. I was initially worried about burning my plants, but have found that most healthy adult Nepenthes can grow quite close to the bulbs with minimal strain. I was also surprised to see that even plants on the edges of the light cast by my fixtures seem to get along quite well.
I'm trying to get more bang for my buck out of my lighting setup these days though, so I was hoping to consult some other T5HO growers about the geometry of their setups. How far away can you move your plants from the fixtures before you start to see signs of insufficient light? Most of mine are eight to thirty inches from the lights, depending on height, but even the vines that have grown clear off to the sides of my racks seem to do OK with little to no direct light to their tips, which leads me to believe that I could light a much larger space with clever placement of my lamps.
Pics, measurements, anecdotal evidence or academic papers are all welcome and would be a great help in my deciding how to proceed. Thanks!
~Joe
 
Mark and I both have our 8 bulb T5H0 fixtures 3ft. above or grow areas.
 
Really? 30 inches away from the lights? Wow, that's impressive... I've always kept my Nepenthes withing 5 inches of the T5 fixture, so that their leaves would begin to show color... :)
 
It took a lot of drum beating by Joe and Av8tor before I got into the T5 HO lamps but I'm really happy with 'em so far too. I'm using 4x T5HOs over my new High Land tank at 20-24" above the pot tops and it seems to be doing well and not nearly as hot as I had imagined T5s would be over a HL tank. I know it's not a Nep but I see today that my nearly leafless Utricularia humboldtii is at least flowering! I don't hardly ever get any leaves on it but I can have a flower stalk... LOL


Pet T5 High Output fixtures are not the same as T5 fixtures from the hardware store.
 
I got 2 55watt plls (basicly just t5ho bent in a U shape)
Some lowlanders show signs of exessive light (hookeriana) at about a foot below the lights.
Dews get bright red about 6 inches below them.
I got my seedlings and other stuff about 2 foot below them and they look well.
 
I still have a blister on my thumb from where I touched a bulb for a split second. HOT HOT HOT!!
 
Tali I have some of those, a set of 2x 55/65W and a set of 2 x 98 W they're nice to get good light over odd sized tanks. I like the T5 HOs better cos replacement 6500K full spectrum daylight bulbs are only $5 each compared to $20-30 each for the PL lamps. But thankfully both type of bulb last a long time compared to normal outputs.
 
mass said:
I still have a blister on my thumb from where I touched a bulb for a split second. HOT HOT HOT!!
Click to expand...

Wow, really? I've touched the lamps momentarily and it kind of hurt, but didn't have any lasting effects. But then, I frequently singe my fingers while cooking so they may just be used to it. The other day I got a little too close to my soldering iron while I was feeding solder into a joint (pro tip - always have lots of slack between your fingers and the tip of the solder) and it hurt like heck. Smelled like burnt pork, scorched black and white, and I was sure it would blister, but after running cold water on it the burn mark washed off and there's no blistering at all.
Well from the sound of it, two to three feet is about the maximum most people use. I guess I'll leave a few shelves how they are now and move all my short plants to those, and set up another for the tall ones where the lights are a foot or two above the canopy. Has anyone tried distances of four feet or more? I know these aren't as bright as HID lamps but I think I could satisfy at least my houseplants with one fixture this way and some light from the window to supplement.
Pet, I do think we may be talking about different classes of bulb. At what wattage are your fixtures rated? I get good coloration even out to the two-foot range with my lights. (That said, I was also able to get coloration using six T12 tubes at the four- to eight-inch range.) Holding my hand six inches from the warmed-up fixtures gets uncomfortable after a few minutes, and starts to feel like a sunburn after 20-30 minutes of continuous exposure. I've got one N. sanguinea vine that's getting close to the six-inch mark, and the pitchers look great as a result, but the leaves are more short-lived than growth points on the same plant elsewhere and they clearly show signs of light stress - reduced size, light green coloration, premature yellowing, etc.
~Joe
 
I get my bulbs for 5 euro each, t5 would be more expensive for me bec i can only get those in bulk.

Something also worth considering is what kind of reflector ppl use.
 
  • #11
Ah I see. Yes those are nice, the 4 ft tubes are twice as bright so have more reach than the shorter tubes.
 
  • #12
Oh man, they really do sound hot. And more powerful than I thought. I mainly avoid them due to the heat problem. I have a hard time with just the heat from t8's. And with limited space, I'm not sure I could place my bulbs high enough above my plants to avoid burning them, especially as they vine.
 
  • #13
Nightsky, if you have trouble with the temperatures from T8s than stay away from the T5 HOs. There is no noticeable temperature increase with my T8s, but with the T5 HOs it's like having a heater in the living room.
 
  • #14
I'm going to hijack this thread a little bit and expand the conversation out to T8s. I'm really struggling with the choice between T8 and T5 at the moment. Every single sign seems to point to T8s as being the right choice for me:

  • T8s are cheaper to buy
  • T8s are cheaper to run
  • T8s run cooler, and I already have issues with heat in the summer, even in ambient room temperature alone!
  • T8s are more readily available at local stores

The only problem is this: I built my Nep shelves tall... about 2.5 feet each. I have plants on one shelf now but am about to buy and mount lights to another shelf... hence my question. After redoing my rack last weekend, I now have my neps 14" from my lights measured from the top of the pot to the tube (just checked this morning). The shelf I'm about to build is a little bit taller than that one.

I've got a lux meter on order so I can make a more educated decision, but in the mean time, does anyone here have experience growing Neps under T8s at distance that might be able to humor my musings?

My fear is that T5s are really the only choice that makes sense given my current configuration!

Cheers!
 
  • #15
not so sure how you can say t8's are cheaper to run, watts are watts... regardless of lighting format

4 foot T5's are 54 watt and 4 foot T8 are 32 watt so yes, they are cheaper because they are lower wattage and putting out less energy. Since the T8 bulb has a larger diameter you have less luminance and a much less efficient reflector. So at the end of the day, I would argue that T5's are cheaper to run if we look at the actual energy the plant recieves per electrical watt of energy consumed.

Again, T8's run cooler due to their larger physical size. This larger size disspates their heat loss over a greater area, likewise since they are only 32w compared to the T5's 54w they will definitely generate less heat. So you are producing less heat and spreading that heat out over a great surface area.

If you have 54 watts of T8 in one room and 54 watts of T5 in another room of equal size, I would say it is safe to assume you would see a nearly equal temp rise in each room. Even though the T5 would hotter to the touch.

And careful with Lux meters, they may be wavelength dependent (and likely are, you need spectrum analysis to really see the big picture)

Cant really make such black and white statements mate,
Av
 
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  • #16
Thanks Av! Yeah don't worry, I know the efficiency argument very well; that for a given number of watts, T5s convert one form of energy into another with less loss to heat. That's clear... I'm simply talking about the raw power usage of T5s vs T8s - if I ran a 4-bulb T5 fixture instead of 4 T8s I'd be using 216 watts instead of 128. My landlord, who pays my electric bill, would not appreciate the difference :)

I was really asking for people's experiences relating to T8s and how high people run their lights over their Neps with good results as compared to the same question with T5s.
 
  • #17
If you simply want to know how close to put your neps to your T8, I'd say about 6-8 inches is ideal. It's unlikely you will burn them with a T8, so there's no problem in trying it even closer if you feel they could use more. At this time of the year, I'd say you could start moving down to 12 hour cycles, too.
 
  • #18
Im guessing you guys have fans running along with the t5s?
 
  • #19
I'm running 4T5 54watt at nearly 2.5 - 3' and it isn't enough to get decent colour on my plants. I think you need atleast 8T5 for that distance. I would say depending on the genus of CP, you have to go a lot closer. For neps, I think 1-2' is the maximum.
 
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