Number of Light bulbs on Shelving Rack

[Happypaphy7]

So this should be my final questions regarding light set up.
I know there are different ways to set up light stands, but given the very limited space, I would like to have as many layers as possible per light set up.

I plan to have two shelving units ( 48 in'' W x 18 L x 72H), and would like to have three layers on each.
I was initially thinking four layers, but I realized that that would not be possible considering the distance between the plants and the light.

Anyways, I was thinking of getting 4ft 4 lamp T5HO, but then after seeing the picture of papheteer at http://www.slippertalk.com/forum/showthread.php?t=36844

I see that the distance between the plants and the light has to be quite a bit if I were to use 4 lamp T5HO (his top layer), meaning I could only have two or so per unit.

I am now thinking of getting two individual 4ft T5HO with snap on reflectors per each layer. The website I was looking at does not offer 2 lamp version that are 4ft, only 2 ft models have 2lamp, but they do sell individual lamp.

In the picture of papheteer, the very bottom layer uses two bulbs of T5HO and the distance between the plants and light is not as great as the top layer, but enough to allow a spike (looks to be a malipoense hybrid?) to develop.

Or should I have at least one layer with 4 lamps T5HO for spiking plants temporarily, and then return the plants back to other layers once the flowers are gone?
In that case, the change of light intensity (although shouldn't be too significant) might upset the developing spikes and buds.

I would also have two or three layers, which is pretty much entire one unit, for just growing seedlings/deflaskings. I guess I won't have to worry about these for a while since they take a number of years before starting to flower.

What are your thoughts??

 

[troy]

I use 2 t8 4 foot bulbs 32 watt 6500 kelvin from home depot total setup cost 30.00 and it works great for me

 

[gonewild]

If you use T8s you can have more shelf layers in your space, 5 shelves. That works well for growing but does not leave much room for spikes.

 

[TyroneGenade]

Go with LED tubes: http://www.homedepot.com/p/TOGGLED-...ht-Bulb-MK2m-T8-48-UN19ND-5080D2-A1/205092985

They won't produce as much heat, so they can be closer to the plants, and they have built-in optics so you don't need a reflector to focus the light. The 60o spread means that at a distance of 1 ft, the light spread is 4 ft wide with the inner 2ft having the highest intensity.

A t5 can put out more light than the LED example above but without a reflector a lot of it goes to waste and even with a good reflector you will only get about 70% of the light directed down at the plants.

If you run two tubes per tier at low current you can improve efficiency and reduce heat that could scorch the plants. The LED lamps should last years compared to the T5s.

 

[Happypaphy7]

If you use T8s you can have more shelf layers in your space, 5 shelves. That works well for growing but does not leave much room for spikes.

How close? like 6 in and under close??
I mean it could work so little seedlings and brachy varieties I geuss.
How many would you use for the width of 18in and the length of 4 ft area?
Two bulbs? 4?

 

[Happypaphy7]

I use 2 t8 4 foot bulbs 32 watt 6500 kelvin from home depot total setup cost 30.00 and it works great for me

I think I remember seeing your set up. gotta revisit that thread, but is that brand new for you yet?

 

[Happypaphy7]

Go with LED tubes: http://www.homedepot.com/p/TOGGLED-...ht-Bulb-MK2m-T8-48-UN19ND-5080D2-A1/205092985

They won't produce as much heat, so they can be closer to the plants, and they have built-in optics so you don't need a reflector to focus the light. The 60o spread means that at a distance of 1 ft, the light spread is 4 ft wide with the inner 2ft having the highest intensity.

A t5 can put out more light than the LED example above but without a reflector a lot of it goes to waste and even with a good reflector you will only get about 70% of the light directed down at the plants.

If you run two tubes per tier at low current you can improve efficiency and reduce heat that could scorch the plants. The LED lamps should last years compared to the T5s.

Thanks for the input.
As you say, LED is great in that they produce little heat and the bulbs last much longer, and cheaper to run (now that doesn't matter any more luckily).
With that LED T8 you show me here, I would have to buy ballast (?) to insert the bulbs on, right?
I am completely lost when it comes to these kind of stuff and rather buy something that's already made and ready to use.

I just want to buy the products sold at this website who specializes in indoor plant growing.
I just want to make sure how many bulbs I have to use per layer.

I was initially thinking to buy 4 lamp unit of T5, but then that will be way too bright unless I give a lot of space between the plants and the lamp.
and they do not make 2 lamp for 4ft length, so I was thinking of getting an individual lamp with snap-on reflector.
Now based on what I saw on others, I am guessing using 2 lamp T5 with the distance between the plants and the lamp of about 1ft should work? I hope.

I guess I can adjust as I go by observing how the plant growth differs, but hopefully nothing disasterous happens.
Just in case, I'm trying to get rid of some plants. Tough decision. lol

 

[gonewild]

How close? like 6 in and under close??
I mean it could work so little seedlings and brachy varieties I geuss.
How many would you use for the width of 18in and the length of 4 ft area?
Two bulbs? 4?

About 12" give or take. That allows you to have 5 shelves in a 6 foot tall rack. Seedlings will grow well at that distance and as they grow the leaves can almost touch the tubes and the foliage will be fine.

On an 18" wide shelf I used two shop lights with 2 tubes each. So 4 tubes per shelf. You can turn off one set if you want less light or heat at times. Or you can twist loose one tube in each fixture to have less light more spread out. It really works well without much heat build up and the fixtures are cheap and you can set it up in a few minutes. Easy yo plug it into a timer.

 

[gonewild]

About 12" give or take. That allows you to have 5 shelves in a 6 foot tall rack. Seedlings will grow well at that distance and as they grow the leaves can almost touch the tubes and the foliage will be fine.

On an 18" wide shelf I used two shop lights with 2 tubes each. So 4 tubes per shelf. You can turn off one set if you want less light or heat at times. Or you can twist loose one tube in each fixture to have less light more spread out. It really works well without much heat build up and the fixtures are cheap and you can set it up in a few minutes. Easy yo plug it into a timer.

I just remembered one more thing I did to that setup.
I put each fixture on a separate timer (the little ones sold for Christmas lights). I set one fixture on a shelf to come on at daylight. Then about 2 hours later the other one comes on also. This mimics early morning low light and then mid day full light. Then 2 hours before lights out the morning set turns off creating the late afternoon light level.
I don't know if it made any difference to the plants but it made the lighting interesting to be around.

 

[TyroneGenade]

This one can be connected directly to the mains: http://ledradiant.com/led-lights-by...ting/18-watts-led-t8-tube-cw-single-end-power (and is more efficient than a T5 or T8).

 

[naoki]

I saw this LED shop light at Walmart today. The spec. seems to be pretty decent. 4200lm from 40W (105lm/W) for about $40.

http://www.samsclub.com/sams/4ft-led-shoplight-shoplight-led/prod16460030.ip

I would start from 2 units per shelf and treat it as a T8 shop light (6-12" between the top of the leaves and the light). It pays by itself (over T8 shop light) in about 1 year with 12h/day.

Electricity cost over a year:
T8 2 bulbs: 64W * 12h * 365 days * $0.2/kWh / 1000 = $56
LED shop: 40W * 12h * 365 days * $0.2/kWh / 1000 = $35

Cheap shop light is about $15 (with bulbs). So after a year
T8: $15 + $56 = $71
LED: $36 +$35 = $70

I'm not sure about the build quality of Lights of America brand (it is an inexpensive brand), though.

 

[Happypaphy7]

Wow~ I like this a lot!
Thank you so much!

I thought LED are very long lasting, but do you think I would still have to buy new one each year? I mean I don't really care about the money since it's cheap, but just curious.

Plus, it says it gives off 4,200 lumen.
Isn't that too little light? I just did a quick conversion online, and that comes out to be 390 fc??

Do all LED give out same or similar wavelength?
This can be used for growing plants?

The main appeal of LED to me other than longevity, is that they produce little heat. and this model looks like a regular florescent light bulb, so I love it!!!

I hope they deliver to NYC. I've never bought from Sam's club.

 

[naoki]

The diode itself can last for a long time (as long as the heat is dealt with adequately). But some other electronic components may fail in the driver.

I would get only as much as you need for now (i.e. I wouldn't equip all shelves if some shelves are for the future expansion). You can check how long it will last. Hopefully it will last at least 2-3 years, and by that time, you'll be able to get much cheaper light with much higher efficiency.

I linked to Sam's club, but our local Walmart had it. I don't remember of seeing Walmart in NYC, though.

lumen is the total output, so you can't easily convert to foot-candle (which is like density). So if 1 lumen of falls onto 1 square-foot, it is 1 foot-candle. But here is rough calculation

Let's say your shelf is 6 square-foot (4' x 1.5'), so if all light from two units (8400 lm) falls onto one shelf, you'll get 1400 fc. However, there will be lots of wasted light not falling onto the shelf (especially if you have to keep a long distance between the shelf and the light fixture), so you'll get much less than this. Maybe 600-700fc or less? Since it is a continuous light (not natural light), it should be good enough for most Paphs. If you surround the shelf with reflective materials (basically like a grow tent), then you can reduce the waste. Hydroponic shops have mylar reflective materials, white cardboard, foil backed foam board, aluminum foil etc. can be used. But if you surround it, you can't utilize the natural light.

As several of us mentioned, fluorescent light has a higher lumen values, but since light is emitted to all direction, there is more wasted light than directional LEDs. I'm guessing that this LED probably gives similar amount of light to plants as 2 bulb T8 shop light.

No problem with the emission spectrum. I think this one is 5000K. There are variations in the spectra, but most of them (5000K or less) look ok for plants. I personally prefer 4000K or 3000K. I don't have a scientific reason for this choice, other than the fact that the spectrum looks well balanced without too much blue, and the efficiency doesn't get suffered too much due to lots of phosphor (lower K). If there is a choice, go with lower CRI (70 or 80 rather than 90) with white phosphor based LEDs because of the better PAR efficiency. These are very small details, which you can (should) ignore.

 

[Happypaphy7]

Thanks, again.

While the cost is not too much, the fact that I now have to spend extra several hundred dollars (given that I have to buy new bulbs each year) that I could otherwise use to buy plants. Oh, well...

I would still have sunny windows to grow orchids, but the light set ups will be away away from the windows that they will have to rely exclusively on the light bulbs.
This particular LED in discussion, comes equipped with some sort of reflector. Do you think it's still not as good?
I could easily put up reflective material but I would worry about the blocking of air flow. hmmm

So, two units of these, meaning total of 4 bulbs per each shelf, is what you recommended, right?

Regarding K, does it actually matter to plant growing?
I thought it was used to show how the artificial light looks in comparision to the natural light. Or was it CRI?
The 5T HO I was thinking of getting from hydroponic website has 6700K.
I think I will still buy that unit, but since they release so much heat, I will use it on top shelf, also place something that is spiking since I could place further distance between the plants and light.

Now I feel better because I can have four shelves as I originally wanted.
I plan on placing little seedlings and plants that are not in spike under light set up with shorter distance (6-12") between the plants and the light bulbs.
I will put the ones in tall spikes up on the top shelf where they are allowed to grow their spikes.

Other large bulky plants like complex hybrids and multiple growths plants along with sun lovers will sit by the windows.

There is no Walmart here.
They made some noise when they tried to get into Manhattan a couple of years ago, they launched major campaign on TV and give out papers and everything.
Well, at the end, I never heard anything and I don't see them around, so I guess they gave up.

I think big box stores and big super market chains killed off pretty much all the old smaller businesses enough, and we don't need even bigger guys.
I don't know. These mega stores are very convenient but I miss old school small stores sometimes. I mean there are still a bunch little places but they are usually not my first choices. OMG, totally off topic. lol

 

[naoki]

While the cost is not too much, the fact that I now have to spend extra several hundred dollars (given that I have to buy new bulbs each year) that I could otherwise use to buy plants. Oh, well...

Yeah, electricity of artificial light costs quite a bit once you start to have more. It was costing me a couple hundred a year a couple years ago. With the increase in the efficiency (I mostly got rid of fluorescent light), I hoped that the yearly cost would go down, but somehow the grow area seem to keep expanding...

This particular LED in discussion, comes equipped with some sort of reflector. Do you think it's still not as good?
I could easily put up reflective material but I would worry about the blocking of air flow. hmmm

Even with reflectors, there will be a lot of wasted light. But you can modify as you go.

So, two units of these, meaning total of 4 bulbs per each shelf, is what you recommended, right?

Yes, it is similar to 4 bulbs of T8 or 2 bulbs of T5HO with 2 units of the LED shop light.

Regarding K, does it actually matter to plant growing?
I thought it was used to show how the artificial light looks in comparision to the natural light. Or was it CRI?
The 5T HO I was thinking of getting from hydroponic website has 6700K.

In a nit-picky mode, the color temp should influence some aspects of plant growth and possibly photosynthesis. You probably don't have to worry about it. It all works. If you are interested, here is a very simplified version of the effect of light color on plant morphogenesis:
http://www.bmlhorticulture.com/photomorphogenesis-guide/

BTW, emission spectrum of 5000K fluorescent light is completely different from 5000K LEDs. I don't know why people like higher K fluorescent bulbs, though. I'm guessing that it is a myth; people may be thinking that these higher K bulbs (frequently called as "daylight white") is similar to sun light (far from the truth), so they think it is better for plants. I have measured PPFD of 54W 4' Philips T5HO with different color, and I would say they aren't so different.

I measured PPFD and fc at 12" from the bulb in the middle:
3000K* 82 micromol/m^2/s 533fc
4100K 83 micromol/m^2/s 590fc
5000K* 80 micromol/m^2/s 620fc
5000K 85 micromol/m^2/s 625fc

The one with * are the bulbs which were used for 1-2 months, and the others were brand new. There are some variation in fc, but that is irrelevant. PPFD is all between 82-85 micromol/m^2/s, so for plant's photosynthesis, any of these will work well. If you start to consider the minor details such as the fact that red photon is more efficient for photosynthesis than blue photons, then 3000K T5HO is probably very slightly better than higher K. I have used 6500K T5HO in the past, but I didn't have it at the time I measured these. I'm guessing that it isn't so different.

 

[Happypaphy7]

Thank you for the link. A good read.
I have a small LED light set up in the kitchen and the light panel consists of about 200 individual tiny bulbs in the mix of red and blue, and orange ( I'm pretty sure that's what the manual said, but no clue what that is for, but very limited in number compared to the other two colors).
You can program the light panel for flowering/growing phase and each phase set will give a different combination of red and blue lights.
It's mainly designed for growing common herbs and flowering plants, although I use it for orchid seedlings and miniature.
I've flowered oncidium twinkle, mini phals, Paphs under this thing among others.
I've had it for five years now, but I really don't like the colors; creepy!

Do you know if "whit light" LEDs contain a balanced spectra for plant growths or would different LED products differ in the spectra composition widly??
And is there a way to find out the composition?
How about the one you mentioned from Sam's club??

Also, K value on fluorescent bulbs as I understand it, is a measure of how the artificial light appear to our eyes in comparison to the natural light.
So, fluorescent bulbs with higher K does not mean it has more blue ( spectra wise) light?
There's this lady in our society who tells people these bulbs must have at least 5000 K to grow orchids. I guess she's wrong, then.

What do you mean when you say the same K value in fluorescent and LED is different??