Converting from T5HO Fluorescents to T5 LED

[Ellen H]

Hi All,

I am considering switching from my current T5HO fluorescent setup (3 4-bulb ballasts using a mixture of 6500K and 3500K bulbs) to the T5 LED replacement tubes. They apparently fit right in to my existing ballasts with no extra wiring needed. The fluorescents generate a lot of heat, therefore the switch to LED to make the room more human-friendly!

The LED's are offered in many different levels of Kelvin temperatures but I don't know what's best for orchids...most of the websites seem to be geared toward cannabis growers. I also do not really understand all the technical terms when dealing with lighting. What info from the spec sheets should concern me regarding what is best for the plants? There is a lot of conflicting info out there. Should I go with a "full spectrum" bulb and not try to use a blend of different Kelvin bulbs?

Also, do I really need what they are calling "LED grow lights" (VERY expensive) or would a much less expensive LED meant for homes/offices work just fine? The office-type light sites don't mention much about color spectrum so I'm not sure they would work for plants. But the "grow lights" do show the spectrum their bulbs generate...however they are priced at 20-40+ USD per bulb depending on quantity purchased (gulp--I would need 12 bulbs).

I'm focusing on "grow lights" by Active Grow, Waveform Lighting, MKB Grow, and Ledgrowlightsdepot.com. They are the only ones I can find offering T5 LED replacements for fluorescent ballasts. Does anyone have any experience with these?

Perhaps I don't need the tubes at all - maybe just install LED strips instead? Or just stick with my current T5HO's?

I grow lots of different types of orchids, from Phals to Cattleyas, and they sit on one of those Home Depot chrome wire racks, using 3 of the 4-foot shelves.

TIA for any advice. I've been surfing lighting sites all day and my brain is befuddled....

[wisdomseeker]

A couple of questions.

What brand of T5HO fluorescent fixtures are you presently using (4ft bulbs? reflectors? type of ballast)?
Brand/cost of tubes you are using now?
Is plant growth and flowering favorable using your existing fixtures/bulbs?

The reason I ask about the type of ballasts used is because most "direct drop-in" LED replacement tubes (aka: "plug & play" or "ballast compatible") usually only work with electronic/instant start/programmed start ballasts.

Lighting can definitely be an extremely complex subject ~ and can definitely be difficult to explain and support. It can also become confusing when technical terms are thrown into the mix (watts, lumens. lux, foot-candles, PAR, PPF, PPD, *efficacy*). Just an opinion for what it's worth... I believe a better way to evaluate light, when applied to plants, is to know the type of light needed to support photosynthesis in plant life (especially understanding the parts of the light spectrum most useful for plants).

So on that note... most good quality light manufacturers provide data and graphs for their products: PAR (photosynthetic active radiation - basically light needed to encourage photosynthesis), PPF (photosynthetic photon flux - basically a measurement of the total amount of PAR that is produced by a lighting system each second), spectrum analysis, and *efficacy*. The "Active Grow" LED tube you mentioned does just that, and the specs look pretty good
https://activegrowled.com/wp-content...Data-Sheet.pdf

Why is *efficacy* useful? Calculating efficacy of a light source will give you an idea of the amount of electricity used compared to the light produced. The higher the efficacy, the more money you will save on your electrical bill. Efficacy = luminous flux/power (Lm/W). The "Active Grow" 4ft. tube is 24W. A typical 4ft. T5HO fluorescent tube is around 54W with an efficacy of around 100 lumens per watt (Lm/W). As to spectral data for a T5HO fluorescent tube, I really like the "Hortilux" PowerVEG PowerVEG FS+UV | EYE Hortilux

Something to seriously ponder if you decide to go with the direct drop-in LED tubes (especially when trying to cut costs with buying 12 tubes)... a mix of these: 5000k T5 LED Tube - 25.5W - 5000K - TCP L25T5D5050K and 3500K T5 LED Tube - 25.5W - 3500K - LifeBulb LBT5F3335B could work for your purposes. As good as the others you mentioned? Maybe, maybe not > might be worth a try.

NOTE
*Well worth the effort & time to read the following if you are truly trying to gain a better understanding of LEDS and photosynthesis... this link is about everything you would want to know about LEDs

http://www.omslighting.com/data/imag...ed_academy.pdf

In regards to my above statements: "know the type of light needed to support photosynthesis in plant life" and "understanding the parts of the light spectrum most useful for plants", these links are worthwhile

http://rsif.royalsocietypublishing.o...11/92/20130901

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2807594/

[Connie Star]

I'm curious about this too. I have a small set-up in my living room with only 4 2foot fluorescent bulbs of the drop-in kind. It also gets sunlight but not much in the winter. The other thing I have noticed about LED "grow' lights is that some of them make the plants look really odd and the flowers not very pretty and after all, why do we grow orchids?
See First Rays for discussions of color temperature

[Dollythehun]

In July I switched over and got these:

Amazon.com : LED 2' T5 6500K Tube : Garden & Outdoor

I'm happy with them. When you ask for information here you can easily be swamped with technicalities. I read the reviews on these tubes, which was helpful. My plants were already in spike when I switched, so I can't help there. What I can say is these tubes are super bright and run cool. As mentioned, you have to be sure they'll work in your fixtures. (Before I get pounced on, I married a guy with a degree in electrical engineering. Some of the OB discussions leave him confused, so don't feel ignorant).

[Nexogen]

With 6500K, that is the spectrum represented in the figure below and 56.3 lumen/W I think it's a perfect choice.

[Ellen H]

I'm using 3 SunBlaster 4-foot electronic ballasts, daisy chained together, purchased a couple of years ago for about $130 (ballast + 4 bulbs each) and also purchased a dozed 3500K red spectrum bulbs to mix in. They are working well. But, the room gets so hot (spare bedroom) I can't use it for anything else. Hence the possible switch to LED.

I am confused by the terminology, so thank you for clarifying things.

I checked out the 1000bulbs.com bulbs you linked to. Quite a significant cost savings! I don't know how to determine if they provide the right type of light for growth and flowering though. I'll check their spec sheets.

Basically I want to install bright white lights so I can see the plants without the weird red/blue haze, either all the same type or a combo of different spectrums...to support both growth and flowering without switching out the lamps all the time.

---------- Post added at 02:44 PM ---------- Previous post was at 02:39 PM ----------

Woops, meant this as a reply to wisdomseeker.

---------- Post added at 02:46 PM ---------- Previous post was at 02:44 PM ----------

Yes, I would like bulbs that look like bright white light, not that funky red/blue glow.

I totally forgot Ray's site had a section regarding lighting...thanks for the reminder, I'll look it up!

[wisdomseeker]

Originally Posted by Nexogen

With 6500K, that is the spectrum represented in the figure below and 56.3 lumen/W I think it's a perfect choice.

By no means am I trying to start a pissing contest, but I'm a bit confused with your post. 6500K refers to kelvin temperature (sometimes referred to as CCT or correlated color temperature), not spectrum. Science jargon aside: kelvin is loosely used in lighting as an overall measurement for the color temperature of light (sort of like an indicator of the perceived color of a light source). The higher the temperature (K), the bluer the light will appear. The lower the temperature, the warmer the light will appear (more red). Color temperature (K) has little to do with spectrum. You can calculate kelvin (K) from spectrum, but you cannot know spectrum based on kelvin.

A kelvin number (6500k as an example) means there is a strong emission line at that frequency. Kelvin temperature consists of almost an infinite number of wavelengths to produce a perceived color. Different spectral emission patterns (nanometer wavelengths) can produce light of similar color (example: 6500K).

Originally Posted by Connie Star

The other thing I have noticed about LED "grow' lights is that some of them make the plants look really odd and the flowers not very pretty and after all, why do we grow orchids?

A really good point. I like to use light that is beneficial for my plants, but also want light that appeals to "my eye". Unfortunately, some of the LED 'grow lights' consist heavily of blue/red light. Maybe okay (or maybe better than okay for plants) but sure the 'heck' does not look good to my "eye". I personally like to look at my plants under a white light (with a touch of warmth). Many of the LED 'grow lights' with good spectrum and a high CRI (color rendering index) will produce a nice white-colored light in appearance, and it really does justice to both the leaves & flowers of the plant ~ within the 'eye' of the beholder.

Originally Posted by Ellen H

Hi All,

I am considering switching from my current T5HO fluorescent setup (3 4-bulb ballasts using a mixture of 6500K and 3500K bulbs) to the T5 LED replacement tubes. The LED's are offered in many different levels of Kelvin temperatures but I don't know what's best for orchids...I also do not really understand all the technical terms when dealing with lighting. What info from the spec sheets should concern me regarding what is best for the plants? There is a lot of conflicting info out there. Should I go with a "full spectrum" bulb and not try to use a blend of different Kelvin bulbs?

The tried and true mix of 3500k & 6500K has worked for many people for a long time. Opinions will vary (vastly) in regards to your questions about "full spectrum", specific kelvin temperatures, and what's "best" for growing orchids.

[Ellen H]

Super bright and cool are what I'm looking for...whatever works best for the plant's growth and flowering.

My SO is a Physics professor...I love him and his enthusiasm for the subject but I glaze over after just a couple of minutes of his "explaining"

---------- Post added at 03:03 PM ---------- Previous post was at 03:00 PM ----------

Originally Posted by Nexogen

With 6500K, that is the spectrum represented in the figure below and 56.3 lumen/W I think it's a perfect choice.

Ok. So it has a big spike of blue which I understand is more for vegetative growth, right? I'd also need a bulb with more red spectrum for flowering?

---------- Post added at 03:04 PM ---------- Previous post was at 03:03 PM ----------

Sorry folks, I'm really messing up the "reply" to specific posters. Sorry for any confusion.

[Ray]

Anecdotally, plain old warm white seems to be adequate.

Grow light bulbs that put out 50-60 lumens/watt are grossly inefficient; even some of the cheapest white lamps put out in excess of 100-120.

Finding retrofit lamps to replace the T5's might be aesthetically best, but might be pretty costly. As I'll be moving to lights over this winter, I'll likely invest in several of the Cree floodlights available from Home Depot.

[Dollythehun]

The replacement tubes I got were equal in price + or- to 1 Sunblaster 2' LED.