My T5 growing lights are just so much better than my regular shop lights.
I was thinking is there was an adapter to convert my light fixture from a T8 to a T5 lights.
I just found these T8 to T5 converters. Has anyone else ever heard of them?
I think they go in the T8 lamp holders and a T5 will fit in between.
I would be interested in knowing that as well. I just checked out my set up (I had no idea that regular shop lights were T12 - I'm rather ignorant in this department!) and see I can use T8 or T12 in my fixtures. If the T5 are really so much better it would be great if these converters really work (don't want a short or a fire!). So hope someone knows the answer!
I did same googling and see some safety concerns (although since these are open shop fixtures they don't really seem to apply) and also one really important fact -- T5s in these adapters will have less light output than the original T8s.
The problem is that T5s use a different ballast from a T8 or T12. They may light with the wrong ballast but both light and ballast will will have a shorter life. How spectacularly the ballast fails I have no Idea.
Doug, the adapters have an electronic ballast built into them. I find the notion of running with both ballasts pretty odd but the lamps themselves should probably be fine. I'm not sure what it would do to the ballast in the fixture.
The people at the lighting store where I buy my T5 fixtures told me that in addition to buying the adapter plugs you also have to change the ballast in the T8 fixture to a ballast that works with T5 bulbs. They quoted a price of about $40 for all of the parts plus another $10 to $20 for labor if they do the conversion. But they also recommended that it's probably better to buy new 2-bulb T5 fixture that they sell for $60. .
I am so grateful for this thread. I never knew the difference between the T's but after drthor brought this up I began googling for all kinds of info. After looking at many sites with adaptors and info on replacing the T12 or T8 fixtures, I realized it would probably be cheaper just to use up the old T12's I have until they burn out and gradually replace when with the T5 fixtures. It appears that one can still buy T8 bulbs which are also compatible with my fixtures but everything seems to indicate that the T5 bulbs are better.
If I have understood this all correctly one T5 bulb can replace 2 T12 bulbs so it makes sense to buy a new fixture. Then I will still be hanging 2 fixtures per shelf like I have now but be using 2 bulbs total instead of 4. Is that correct?
gardadore, I'm in the process of outfitting lights for this season & also down the road. The T-12's are the bottom end of the totem pole. The T-8's are in the middle, pricewise & light output. The T-5's are the top-of-the-line, and most expensive.
Using either the T-8's or 5's, you will more than likey HAVE to use 4 lights per shelf. By just using a 2 light fixture, you will have seedlings looking for light. Depending on the shelf you have, you need to be able to adjust the height of the lights, or the seedlings. I did a lot of shipping & I use Priority Mail boxes of various sizes to raise the seedling trays closer to the lights. They're free from the post office, have sealed ends, and they work great, and you can also use UPS boxes.
Lowe's has a 48" X 18" deep by 74" tall wire shelf unit, that will hold 4 1020 trays & the 48" lights will fit it perfectly. Coupled with the T-8 lights & bulbs, you could germinate 12 trays of seedlings at a time. The total investment would be about $150, but you could add lights as you needed them. Lowe's just lowered the price on the shelf unit to $70, so now is the time for me to make this jump.
What's nice about this set-up you can have seed mats on upper shelves while potting up previous starts on another shelf, and keep the room cool & have new seeds germinating at the same time.
Thanks Kevcarr for the helpful info. I already have the 5 tier shelf set and have been using two 48" fixtures with two bulbs each for a few years. I have them hanging on chains which I can let down or hook up as needed. I think I even got the shelf unit at Lowe's and it is great. I know I will still need 4 T-8 bulbs but was questioning the T-5's. What I don't know and need to check is how many bulbs most 48" T-5 fixtures normally take - one or two or more. There seem to be T-5 fixtures that take up to 6 bulbs as well. I see the bulbs are thinner than the T-8 or T-12's. Keeping up with all the new technology sometimes makes my head spin!! You can't just wave your hand and say, "let there be light" without all kinds of research and adherence to new regulations!! LOL
kevcarr59 wrote:I did a lot of shipping & I use Priority Mail boxes of various sizes to raise the seedling trays closer to the lights. They're free from the post office, have sealed ends, and they work great
I'm pretty sure they're not offered "free" to hold up your plant trays.
And people wonder why the USPS is stopping Saturday delivery...
rjogden, glancing around the workshop I was looking for something to raise the trays I was starting. I had some leftover boxes that I hadn't used that caught my eye, so I figured I'd put them to use instead of throwing them away. Reuse, recycle. I generally keep 80 or 90 percent of boxes that we receive. I've got to get cardboard to put under some new mulch for our bed, so I'm going to a local store and getting their boxes out of the trash... Another freebie... I'm sure my half-a-dozen boxes didn't lose USPS 16 BILLION last year...
Nicole, I also wish USPS would just deliver checks & keep the junk mail & bills...
gardadore, I would have liked to go to the T-5's, but they are so much more expensive than the T-8's, both the bulbs & fixtures. You're not going to gain a significant difference between the 5's & 8's like you would get from the 12's. I had a hodge-podge of a little 24" grow light, a 4' T-12 with only one bulb working, and a couple of clamp-on 100 watt CFL's beginning this season. I've added 4 T-8's with another 2 showing up next week, and I'll be set for the future.
Ok, I'm totally confused...I usually start about 3000 seedlings a season. I'm down sizing this year. I've always used plain cool spectrum shop lights which get me perfect size seedlings in about 6-8 weeks. What would be the advantage to spending more money on different lights? It seems as tho there is a large price difference are the results that different?
Lisa, those are my sentiments exactly as to the added expense of the T5 lights. Using Lowe's pricing for the T8 light fixtures at $15 @, and the bulbs are $34 for a 10-pack at Home Depot for the Phillips lights. I prefer the Phillips over the Sylvania's bulbs.
A similar T5 fixture is around $115 at Lowe's, & about $80 for a similar one at Home Depot. The T5 bulbs are about $40 per 6 bulbs, so they are more expensive also. I just can't see the reasoning to spend upwards of 4 or 5 times the money for a set-up that is very close in results. If someone did a controlled study with absolute identical conditions, with the only variable being the lights, then I may consider the expense.
If I were going start from scratch and had a large enough budget to use the T5's, yes I'd use them because they may be a little more efficient and have more light output. With the budget being what it is, I have to buy the best for what I have to spend. It's hard to justify buying one light fixture & bulbs versus 4 T8 systems with bulbs for the same dollars. The maximum I could seed with 1 light is double what will be under the T8's, and isn't production what we're looking for when we germinate our seeds.
I have a source in Lewisville, TX where I buy the 2- bulb, 48", T5 fixture including bulbs for $60. The 48" T5 bulbs alone are $4 each.
I also just purchased a 48" 6 - bulb T5 fixture including bulbs for $172.66. I'll be glad to provide the name and address of the store if any one is interested.
hrp50 ... changed question:
have you noticed any difference on growing your seedlings with T5 compare to the light you were using before?
Is it "very close in results"?
or "why didn't I have those lights before"?
This is only my second season to start tomato seedlings and I've never used anything other than T5 lights. The first season I had very poor results for reasons that are unknown. This year has been much better but I have increased the number of T5 fixtures so the seedlings are getting more light. That's the key I believe.
Wow, what a timely thread. I need to expand my lights and have been trying to decide between T8 and T5. I've spent HOURS on the web looking at options. While the T5's are supposed to be more efficient, my concern about the T5 might be heat.
For drthor and others who have used, both: Is there a noticable difference in the heat output of the T5 over T8? Are you able to keep your seedlings just inches below the T5 lights like you can with a T8 fixture -- or, is it not as important to get the plants as close because of the extra light?
FWIW, I had used the T-12 shop lights last year along with a grow light, with mediocre results. This year I have the T-8's and the difference is remarkable. I use the DAYLIGHT bulbs, and their temperature is 6500K, which is the highest I know of. They have the bluest light which is my personal preference, and they seem to work fairly well so far this season.
I don't think either the T-8's or 5's throw off much heat. We're supposed to get some colder weather in the next couple weeks & with just a little space heater the room is staying about 65-68 degrees. I'm fairy happy with the results thusfar, so I think I will continue doing what I'm doing.
I noticed on another thread that somebody mentioned that the grow lights put out too much heat at even 18" away from the plants. I can't remember the details...but they wanted to keep their seedlings in the 60-70 degree range like commercial growers do, to prevent legginess and get nice stocky seedlings.
My experience has only been with shop lights but I do have stocky seedlings.
you did ask a very good question and I am posting pictures for you to explain this really better:
#1 and #2: Those seedlings are under T5 lights. The 6 light bulbs fixture seat on top of my shelf. I never move the light down or the shelf up. T5 lights are really strong and they don't need to be closer to the seedlings. It is just like growing plants under sun light. The lights give some heat which is just perfect for germination. The seedlings DO NOT stretch to the light, instead they just grow like if they were under the sun. If you are growing a tomato under a T5 light, the nodes between the leaves are shorter, while under a T8/T12 light the plant will just stretch to the light creating a large space between each leaf. Look at picture #5: peppers and eggplants under T5, can you see that they are not stretching for the light ... but just growing
#3: T8 light needs to be very close to the seedling
#4: Upper shelf T5 lights (see how far away they are from seedlings) - bottom shelf T8 (must be 1" closer to the plant and tomatoes try to reach the light as fast as they can)
When I grow tomatoes I don't mind T8 lights because the plants will stretch to the light creating a longer stem (which I like to have on a tomato plant because I transplant out using the trench method).
But I do mind with the other crops. I don't want leggy/weak plants.
I did find those lights at a better price. Also some of the stores sell used one.
I love my 6 bulbs fixture because it has two switch: I can use 2, 4 or all 6 lights as I need.
The reflecting metal behind the lights shine in a very large surface.
kevcarr59 wrote:I use the DAYLIGHT bulbs, and their temperature is 6500K, which is the highest I know of. They have the bluest light which is my personal preference, and they seem to work fairly well so far this season.
Higher frequency bulbs are available, but you won't find them in the hardware store. They are used widely in saltwater aquariums to increase the available light spectrum and for their bluish-purple tone. (Those bright blue heads lights on some cars? 10,000k HID.) I think reptile keepers use some of the higher frequency bulbs, too, to mimic high intensity sunlight.
10,000k, 12,000k and 20,000k are available in T5 and T8, 21,000k is available in T5 only, I think.
Personally, I choose 6500k or 6700k for maximum overall plant growth at a single temperature.
drthor -Thanks for taking time to take pictures and explain. That was so helpful.
I think you said you were adding another shelf of T5 lights. Do you have anything growing on the shelves above T5 lights yet? I'm curious if the heat radiating up will be an issue. I mostly grow tomatoes. Would you be at all concerned about putting tomatoes on a shelf above a T5?
another great question.
I was worry about the heat too until I installed the light and realized that the lamp on the top is just a little bit warm. Also it is about 6" down from the upper shelf.
Actually, if it will get hot it will be great for the upper shelf ...so I will not need to turn on the heating mat ... but I don't think this will be the case.
Right now the upper shelf is empty because I wanted to try the new lights in the second shelf.
I was worry that since the new fixture has only 4 bulbs the plants on the outside of the shelf will turn their head to the light ... NOPE ... the reflecting metal around the bulb shine in a very large area and the plants are receiving all the light the need.
Tomorrow I will start some cucumbers and okra seeds on the upper shelf. I will raise my heating mat up to 90F.
If the radiating heat will be a problem I will post here.
If a T-5 bulb is marked "HO", it is probably high output (brighter), not more efficient.
T-5 bulbs can be twice as bright as a T-12, so it would make sense that they would produce twice as much heat if they were as inefficient as T-12s.
I don't know if High Output T-5s are more efficient than T-12s - T-12s waste a lot of electricity, and wasted power comes out as heat - just they aren't AS efficient as regular or HE T-5s.
But a regular or "high efficiency" T-5 that was only 50-60% brighter than a T-12 ought to produce no more heat than a T-12. I'm guessing that only an HO T-5 would produce more heat than a T-12. I bet HO T-12s also run hotter!
Hmmm, I see that the name "HO T-5" SOUNDS hot!
There's a theory for why the surface of a T-5 bulb might be hotter (temperature),
even if it produces less heat than a T-12.
A T-12 tube is one and a half inches in diameter, but a T-5 is only 5/8" in diameter. That's 2.4 times narrower.
So the circumference of the T-12 is 5.75 times more than the circumference of the T-5 (2.4 squared).
If the bulbs produced exactly the same amount of heat, the surface of the T-5 would have to be a good bit hotter to let it all out. For the same heat to escape from the bulb through 1/6th of the surface area, it would almost have to be hotter. Unless there was a fan, or the reflector was ventilated.
If a leaf touched the T-5 bulb or were within a few millimeters, it wouldn't surprise me if it got hotter.
But if the T-5 bulb were far enough away that the leaf got the same brightness as it got from the T-12, I think the leaf would be cooler, just because higher efficiency means less heat.
But another way to look at it is, if you have enough T-12 bulbs close enough that your seedlings have all the brightness they need, you don't need more brightness.
Might as well wait for your current magnetic ballasts to burn out, and the prices of T-5s to come down further, before pursuing savings in cost of electricity and the convenience of adjusting light height less often.
By then there may be ultra-efficient T-5s developed for an intermediate brightness range, for more savings and even less heat.
The T5 light fixtures I have don't really produce more heat than the T8 ones I have.
I am able to start both spring and fall crop with no problem. The fall crop doesn't stay indoor very much, compare to the spring one.
Here is a picture of my new T5 fixture. It is hanging on the second/middle shelf. The top of the fixture is just a little bit warm .. like a normal light fixture, nothing more. I am very happy.
Maybe soon I will get a third light and I will be all T5 !