Aquaponic Plant Lighting
It’s that time of year again. For those of you like me whose aquaponics system has been relying on the free plant lighting that Mother Nature provides, this is the time of year when you have to decide: to supplement or not to supplement?
The purist locavores will tell you that eating in season is part of the gig. That it is the pact we make with Nature to replace the joy of summer produce with winter squash and potatoes. To that I say “hogwash”! I don’t have to wash my clothes in a stream, I don’t have to churn my own butter or milk a cow, and because of advances in grow lighting technology, I don’t have to give up on tomatoes and peppers in the middle of the winter. (I apologize if that was offensive to my locavore friends!)
I supplement the shortened natural daylight that pours through my greenhouse with HID grow lights that come on at “sunset” and go off at 9:00 p.m.. This allows me to grow not only the herbs and greens that do well in a day with the 11 hours of sunlight we are now receiving, but also grow the fruiting plants that crave the longer days of summer.
A recent exchange on our community site shows the confusion over the different types of plant lighting that are available today. I know a thing or two about grow lights, and recently gave a presentation on the subject, so I posted some thoughts. Members seemed thankful for the guidance so I thought I would share them here with you as well.
When you select and run lights for your plants consider:
- Duration – As I said above, how long you run your lights will depend on the day-length requirements of your plants. Are they fruiting (e.g. tomatoes) or foliage (e.g. lettuce) plants?
- Spectrum – Be sure that you are covering the blue and red spectrums that are absorbed by plants.
- Canopy penetration – The light should penetrate deep enough into the plant’s canopy to effectively get light to the lower leaves. A tomato plant has a very different canopy depth than a lettuce plant.
- Heat – Some light sources produce a lot of heat. This can be a good thing when you are trying to heat a greenhouse in the winter, but not such a good thing if you are growing in a small, enclosed room within your house.
- Energy input for light output – Some fixtures require a lot of power, some are fairly energy efficient.
- Cost – Consider all facets of cost, which include the original cost of the size fixture required to grow the plants you want to grow, the cost of the replacement bulbs, the frequency of replacement, and the cost of the power to run the light.
Below, I evaluate the 3 main types of lighting options favored by indoor gardeners using the parameters listed above.
Florescent Lighting using T5 bulbs – T5s are used in indoor lighting
fixtures because they are skinny, so you can pack a lot of them into a fixture. As the number next to the “T” goes down, so does the diameter of the bulb (T12’s are bigger than T8’s which are bigger than T5’s)
- Pros of T5′s – They have a broad plant lighting spectrum so they work for both fruiting and foliage plants. They are also low power use and don’t throw off a lot of heat.
- Cons of T5′s – They will only reach through 18″ of plant canopy. For taller plants (again, think tomatoes) you can put them up sideways. Also their performance drops off significantly after 6 months, even though they still look just as bright as the day you got them. You must replace the bulbs every 6 months of use.
HID (High Intensity Discharge) Lighting – these are serious lights for serious indoor growers.
- Pros of HID – They provide much more intense light that goes through almost any plant canopy. If you get a switchable ballast you can easily move from a high pressure sodium bulb (red spectrum for vegetative growth) to a metal hallide bulb (blue spectrum for fruiting) for an even more precise plant spectrum. Bulbs last at least a year.
- Cons of HID – The bulbs are expensive, they draw more power than fluorescents, and they throw off some serious heat.
- You might find this chart helpful in figuring out coverage if you decide to go down the HID lighting route…
credit: futuregarden.com
LED lighting – one of the newest of the lighting technologies now on the market
- Pros of LED – no heat, very low power consumption, you never replace the bulbs
- Cons of LED – Because these are still new, I have not seen enough data to be confident that they will grow as well as either of the other two options and they are relatively more expensive at this time. Also they cast a very odd light over your plants and give a red glow to the room. A friend who has just started growing with LEDs uses a flashlight to actually see what her plants truly look like.
Here is another interesting chart I ran across recently that shows the light output of some different options…
credit: littlegreenhouse.com
I hope this helps you to make an educated decision about whether or not to help Nature out and extend your season too.
Enjoyed this post? Here are some others you might like:
Posted: October 25th, 2010 under Blog, Growing, The AP Life, The Aquaponic Source.
Tags: aquaponics, grow lights, HID lights, LED lighting, plant lighting, T5 florescent lights
Comments
Comment from slywoman
Time October 25, 2010 at 7:16 pm
Great point, John. Yes, they would be cheaper to operate, but the performance would not be the same. CFLs perform like T5′s and only penetrate a plant canopy 18″ or so. We used CFL’s on the AeroGarden and when we came out with our taller gardens this was always an issue we struggled with (the secret to those gorgeous tomato plants in the photos? Think sidelighting…). Plus you will be hard pressed to find a CFL fixture for 5.3 lights. And you can’t fine tune the spectrum like you can in a switchable HID fixture. Again, it all depends on what you want to grow and which considerations are the most important to you. thanks for the question!
Comment from Mack
Time October 30, 2010 at 7:40 am
I’ve been using two 90watt LED grow lamps for a while and I’ll never use HID lamps again. Sure the set up cost is a bit more but because they use far less power and you buy replacement bulbs every 10 or 15 years they pay for themselves in a year or two over HID. You also noted that LEDs cast an odd light. That’s true for the human eye but the plants love it. Because they are set at a color spectrum that is best for photosynthesis about 95% of the light is absorbed by the plants compared to about 15% for HID. Also you can put the lamps near the plants and don’t have to worry about burning them like with the very hot high pressure sodium or metal halide bulbs. Something to consider when buying LED lamps is the wattage. Some of the cheaper sets sound like a bargain but each LED may only be .06 watt while the better units run at .8 or 1.0 watt per LED and that makes a huge difference so do your research. For more info check out this blog http://tinyurl.com/2cro74p If you do decide to try LEDs I’m sure you will find that they are a great fit with aquaponics.
Disclaimer: I don’t work for anyone that sells LEDs or sell them myself and being new at the whole LED thing I don’t have any suggestions as to best brands.
Comment from slywoman
Time October 30, 2010 at 7:46 am
Terrific information, Mack. Thank you for that! I really do need to try LEDs…maybe this winter.
Comment from Brian
Time November 22, 2010 at 6:13 pm
I would agree with Mack’s assessment of LED’s. I have been growing with two 300W LED’s panels and my plants are in love with them. I live in a hot climate and the reduced heat profile of the LED’s are essential for me. I did a lot of research on LED’s and there is a very diverse spectrum of quality. There are a few vendors that have got their light spectrum balance dialed and offer lights that compete with HID and HPS. I purchased my light from Grow LED Hydro and have been very pleased with the results. I am not in any way affiliated with GLH, but I am a satisfied customer.
Pingback from Home Aquaponics Update : : Formulating Focus
Time December 3, 2010 at 8:30 pm
[...] Our home aquaponics system has now been running for almost two weeks so I felt it was time for an update. As with any project I do I am constantly making changes, adapting new techniques and updating the original plans based on things I am learning along the way. Since the last post we have purchased a “hi-tech” yet economical grow light that uses much less energy. Initially with the T12 ballast, the plants were emerging a little spindly and research suggested that that the lighting was inadequate and that the old T12 bulbs would need to be replaced as they lose their strength over time. So rather than purchasing new T12 bulbs for $20/piece ($40 total) we decided to upgrade to a T5 fluorescent system that produces better light and is more energy efficient (the system came with bulbs and the 4 bulbs that will need to be replaced on a yearly basis are the same price as two high output T12s). Since the switch our seedlings have thickened, straightened, become more colorful and quickly gained their third leaves. (For more information on choosing the appropriate lighting for your aquaponics system check out this blog post at The Aquaponics Source.) [...]
Comment from J Pizzle
Time December 9, 2010 at 10:21 am
HPS lighting is the most efficient source of lighting in terms of lumens per watt, period. Arguments can be made, of course, so look to the commercial pot growers for the answer. They only use HPS. A 600 watt HPS puts out 90,000 lumens, that’s 150 l/w. T5 put out less than 100 l/w, and that is a bare bulb measurement. Almost half of the light any fluorescent makes is lost, reflected back into itself and each other by the fixture body. Remember, too, that most of us APers are growing in greenhouses, and value sunlight above all else. HPS can be hung vertically, casting almost no shadow, just clear glass, socket, and a cord. They produce a red spectrum light that plants need, mimicking late afternoon sun. My bro-in-law just bought some 1000 watt HPS ballasts, bulbs and sockets for $200 each at hydroponicplantlighting.com. Each light will cover a 10′x10′ area without sunlight at all, much larger for supplemental light. It would take 3 1/2 T5 8-bulb racks to equal the 140,000 lumens of one 1000w HPS, totaling 1500w, $1400 and 28 sq. ft of shadow. A 540w LED “mothership” light (they say is better than 1000w HPS) will set you back $2200 plus tax and ship. LED lights also have circuitry and cooling fans like a CPU. Not sure how they hold up in a greenhouse. Also promising is a ceramic metal halide bulb (CMH), a full-spectrum white light made to replace 250 and 400 watt HPS bulbs. Just my opinion. Happy fishing
Comment from J Pizzle
Time December 10, 2010 at 8:02 am
Oops. Correction– should have been plantlightinghydropics.com. My local store just quoted me $190 for ballast, bulb, and 15ft cord/socket, in stock! By the way, heat in a greenhouse isn’t a bad thing. Slywoman, you said you supplement light in the evenings. I kick ‘em on at 4:00 am to fight the frost. Seems that daytime GH warmth will carry thru most of the night, and early mornings is when the added heat from lights is most beneficial for me. Also, total heat per watt is less with HID than LED or CFL. Remember HPS are the most efficient at creating light from electricity, which means they create less heat per watt than other lights do, they just concentrate all that heat at the bulb. That means that you’re total GH temperature will be higher running 1000 watts of T5′s or LED’s than 1000 watts of HPS. LED manufacturers claim that less watts are needed, because their light is ‘tuned’ for plant needs, and that much of HID light goes unused by the plants. If so, I’d sure like to see some proof. LED’s have some good things going for them, like no mercury, no breakable glass, no reflector, long life, no noise… Sure would be nice see a scientific controlled grow to prove the pudding. Has anyone seen results from side-by-side grows?
Comment from slywoman
Time December 10, 2010 at 8:08 am
Again, great stuff Jon. I just saw a side by side over Thanksgiving. We visited one of our retailers in Minneapolis called Interior Gardens – http://www.thegrowlight.com/ – and they had a side by side test set up with HID vs LED. The guys there said they concluded that the LED was a great supplemental light, but they aren’t recommending it be the only source of light for anyone.
Comment from John Shelson
Time October 25, 2010 at 6:56 pm
On your light chart 1 400 watt HPS is equal to 5.3 CFL’s. Wouldn’t it be cheaper to go with the CFL’s?