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Grow Light Selection
There are many choices available for Hydroponic grow lights. A good Hydroponic grow light choice would depend on what we will be growing including the size of the Hydroponic plants, whether they will be flowering and fruiting plant varieties as well as the area size of the Hydroponic growing area.
We must keep in mind when deciding on grow lights that they are all rated in Lumens except for LED lights. Lumens mean very little in relationship to plants. Lumens are a scale designed only for the human eyes and not for plants. When we speak of Lumens it is just an indication of the brightness that we will see as humans. Color spectrum in regards to the Kelvin rating is really what is important in grow lighting for plants. A light may be very bright to our eyes but white light is invisible to plants so Lumens is a bit deceiving in that sense.
There are many types of Hydroponic grow lights including fluorescent Hydroponic grow lights, Metal halide Hydroponic grow lights, High pressure sodium grow lights and special LED grow lights designed for indoor Hydroponic growing as pictured here.
These LED grow lights are the grow lights of the future. They out perform all other grow lights in performance, usable light spectrums and power efficiency.Let's look at some of the different types of grow lights available and how they are different from each other.
Fluorescent Hydroponic Grow Lights
We will start with fluorescent Hydroponic grow lights. Fluorescent grow lights can be placed very close to the plant canopy without any burning of the plants because they run much cooler. Placing them closer to the tops of the plants helps to intensify the amount of light lumens produced by the bulbs.
If you placed metal halide Hydroponic grow lights or high pressure sodium grow lights this close you would cook the plants to death very quickly as they produce way to much heat. Heat by the way when produced by any light source is actually considered as wasted energy.
Pictured here are 4 foot high output T5 lamps. They produce 5000 lumens each and make very good grow lights, not by the lumens they produce but by the color spectrum wavelengths they put out. Fluorescent grow lights can be placed as low as just inches away in some Hydroponic systems with no damage to the plants. In the case of metal halide and high pressure sodium grow lights they usually must be placed several feet above any type of Hydroponic plants.
Fluorescent grow lights on the other hand do not produce nearly the amount of light lumens that metal halide and high pressure sodium grow lights do. So it really depends on what you are growing and the needs of your particular Hydroponic setup. Another factor to consider is the cost. Metal Halide and high pressure sodium grow lights will run up the electric bill way more than any fluorescent grow light setup ever will. Let's look at some different types of hydroponic fluorescent grow lights.
CFL - Compact Fluorescent Bulbs
Hydroponic fluorescent grow lights come in many forms. There are CFL or compact fluorescent bulbs that screw in like a regular light bulb and there are the long fluorescent grow light bulbs that snap into special light fixtures similar to shop lights. There are several types of these long fluorescent bulbs available as well depending on what you are growing. This is a 125 watt CFL grow light bulb that comes in several wavelengths and also in many other sizes. It takes a special larger mogul socket to use. Let's look at some of these fluorescent grow lights in detail.
CFL grow light bulbs can be used in Hydroponic growing. The little compact fluorescent screw in type bulbs are rated in fluorescent watts but usually are converted into incandescent watts so you know what you are buying. Most of the smaller spiraled ones that can be screwed into regular household sockets are useless for Hydroponic plant growing but if you get the right ones they can work very well. In some of our Hydroponic systems we have used some little 6500K 26 watt CFL bulbs that will put out 1600 lumens each which are much smaller than the one pictured above. When you double these up with a Y connector you get 3200 lumens and about 200 incandescent watts per socket which is no joke. Again, impressive to our eyes for the brightness, but impressive to the plants for the good blue colour spectrum of light they put out. You just need to be a little creative when using these little guys.
If you gang up 4 sockets with 4 Y connectors and 8 of these little 26 watt bulbs you will have a light fixture that puts out 12,800 lumens and about 800 watts of good blue incandescent light. Not a bad little fixture for growing smaller Hydroponic plants. Of course these are using fluorescent power so you are only paying for about 200 watts or less of power for all 8 bulbs. We call these 26 watt 6500K spiral bulbs BABY T FIVES because in a real sense that's really what they are. They run cool so you can place them right over the Hydroponic plants. We have grown healthy Hydroponic plants over 12" tall with these CFL bulbs. They are also great for Hydroponic seedlings. They also come in much higher wattages, much higher lumen ratings, different wavelengths to choose from and these bulbs last 8000 hours and more. The larger wattage CFL bulbs will require the larger Mogul socket to screw into to use.
Whatever Hydroponic grow light system you use you can use some Mylar film to line the walls around the lights to intensify the light rays for better plant growth. Mylar reflects light rays and bounces them back into the plant area which gives you more light where you need it. Foil also reflects light in the same way. Mylar film comes in rolls at any good Hydroponic store.
T5 Fluorescent Grow Light
Pictured here is a 4 foot, T5 fluorescent grow light. This is a great grow light for most Hydroponic systems and it runs cool compared to metal halide and high pressure sodium grow lights. We don't even notice these guys on our electric bill because they use such little power. We use these with great success for Growing Hydroponic lettuce and Hydroponic herbs and they do a great job on seedlings and starting larger plants like tomatoes. We can grow excellent tomato plants to about 2 feet high or so under these grow lights.
A grow light unit like this puts out about 20,000 lumens for a four lamp model but it also comes in a 6 lamp model and a shorter 2 foot 4 lamp model. It has solid state ballast and can be hung in the horizontal or vertical position in case you want side lighting. You can choose your lamps with this one depending on what you are growing. This fixture has a very nice reflector that really makes it bright and has a good long grounded cord. We have excellent results with this set up with both 3000K and 6500K high output lamps alternated.
We also have used and still use similar fixtures using high output T8 bulbs. They work well too but really just for smaller plants like lettuce, herbs and small ornamental plants as they don't put out the lumens nearly as well as the T5 lamps. If you are one of those growers still trying to use the old T12 "grow light" bulbs you don't know what you are missing.
The high output T8 fluorescent bulbs beat the pants off the old T12 bulbs and the high output T5 bulbs beat the pants off the T8 bulbs. If you are growing larger hydroponic plants or have a larger area that you need to cover you may need a metal halide grow light or a high pressure sodium grow light if you are doing flowering plants.
High Intensity Discharge
If you need to cover a larger floor area with very intense light you may need a High Intensity Discharge type grow light fixture. These fixtures put out an enormous amount of light. You almost need sunglasses to look at a 1000 watt metal halide bulb it is so bright. Along with being intensely bright they also get intensely hot so they cannot come within several feet of your plants or they will get cooked. If you get a larger wattage bulb you will also need it fan- cooled to avoid any problems.
The larger systems have exhaust type openings to hook up a fan system to. Some of these systems put out well over 100,000 lumens and they do get very hot. If you are installing a larger one in a small room the room will always be hot also. Pictured here is a Sun System 2 fixture and is using a metal halide bulb in it. You can also use a high pressure sodium bulb in this for the flowering phase and this particular unit will take a 250 watt or a 400 watt bulb.
These types of grow light fixtures have the ballast built in behind the bulb socket so you don't have to buy the ballast separately. Ballasts for HID fixtures are not cheap. These are great grow light fixtures and do an excellent job of supplying the needed light to a wide variety of plants including large tomato plants. They will cost more to run as compared to Fluorescent grow lights.
High Intensity Discharge Ballasts
If you end up buying an HID grow light fixture for your Hydroponic plants that does not have a built in ballast system you will need to buy a remote ballast separately. When remote ballasts first came out they were designed to be used with either a metal halide fixture or a sodium fixture but not both. You would need to buy an extra remote ballast or fixture or both. Now they have one ballast that will run either type of light.
Pictured here is a Sun System 10 switchable 1000 watt ballast system that will let you run both types of light from the same ballast. You can switch from MH to HPS and back with a simple flick of a switch. This neat little unit is vented for cooling, has nice rubber feet for controlling the humming sound and has high temperature heavy duty capacitors. This is a nice unit and comes with a 6 foot grounded cord and a 5 year warranty. It also saves you some money having both lighting features built in.
High Intensity Discharge - Bulbs
HID or High Intensity Discharge systems have been used as Hydroponic grow lights for many years now. They normally use high wattage bulbs, either in metal halide for the blue light that plants need for growth or high pressure sodium bulbs for the red lights plants need for flowering and in many Hydroponic systems both are used at the same time. All HID systems burn very hot but put out intense bright light that travels for several feet down to the plants.
What many people do not know is that the light being emitted from such systems is mostly being wasted on the plants because they cannot see it or even use it. It has been proven through science that only about 9% of this intense bright light is being used by the plants to produce Chlorophyll and for plant growth.
A 1000 watt metal halide bulb that puts out over 100,000 lumens sounds impressive. Most of that is not even being seen by the plants and is just producing heat so in reality it is not so impressive. For many Hydroponic growers this continues to be the grow light of choice so we have listed helpful information here regarding HID lamps and what they actually do.
Sodium grow lights put out mostly red and yellow wavelengths and not much blue so plants can become leggy under them. The opposite is true of metal halide as they contain very little red. These are best used combined with each other for this reason. Sodium bulbs can last up to 2 years where metal halide about 1 year and metal halide does have a half life. It is easy to see how using these bulbs can get very expensive figuring that a single 1000 watt bulb can run in the neighborhood of $60 and up. A metal halide conversion bulb that runs on an HPS ballast usually costs way more. HID bulbs last about 10,000 hours depending on the quality.
Here are just some general examples of what these bulbs can do.
A 250 watt HPS grow bulb is 28,500 lumens and optimum growing area coverage is 3'x3'. The same size bulb in metal halide is 21,000 lumens and covers the same growing area.
A 400 watt HPS grow bulb is 50,000 lumens and optimum growing area coverage is 5'x5'. The same size bulb in metal halide is 36,000 lumens and covers the same growing area.
A 600 watt HPS grow bulb is 92,000 lumens and optimum growing area is 6'x6' The same size bulb in metal halide is 70,000 lumens and covers the same growing area.
A 1000 watt HPS grow bulb is 140,000 lumens and optimum growing area is 8'x8'. The same size bulb in metal halide is 110,000 lumens and covers the same growing area.
A 1000 watt metal halide conversion bulb is 119,000 lumens and optimum growing area is 8'x8'. This special grow bulb operates on a 1000 watt HPS ballast.
Let's look at the best Hydroponic grow lights on the market now which is LED grow lights.
And Finally, The Best - LED Grow Lights
We have saved the best grow lights ever designed by man for last. These LED grow lights are truly the grow lights of the future and for many reasons. LED stands for Light Emitting Diode. These state of the art grow lights are designed completely around the science of plant physiology and the light spectrums that they actually use. LED grow lights put out exactly the correct light spectrum wavelengths of reds and blues based on the Nanometre scale of plant growth.
These grow lights, although they look like you are growing plants almost in the dark, produce wavelengths of light that are 98% useable by the plants. This is nothing short of amazing since only about 9% of the light being emitted from all metal halide and high pressure sodium lights is ever used by the plants and the rest is wasted. If 98% usable light versus 9% usable light is not enough to convince you, these LED grow lights use 95% less power than metal halide or sodium lights and they last from 12 to 15 years before needing to be replaced. This means that they last from 10 to 15 times longer than HID bulbs. They burn extremely cool producing almost no heat at all and save an enormous amount of money on the electric bill as compared to any metal halide and high pressure sodium grow lights.
A standard 12"x12" LED panel containing 225 LED lamps will only use about 16 watts of power making them even way more efficient than fluorescent grow lights and 98% of the LED light is actually being used by the plants. A well balanced LED grow light will have about 17% blue lamps and about 83% red lamps installed on the PC board light panel. What is also great about using LED grow lights is that it is very easy to switch your grow lights too high red content for flowering phases and high blue content for vegetative phases by just changing the panel to a different panel. These even come in standard screw in flood light type bulbs that fit any standard light socket.
When LED grow lights first came out they were extremely expensive like any other new product on the market. They have come down in price quite a bit now and are very affordable when you do the math of how long they last. They are way cheaper than all HID grow lights now when you figure you need to replace metal halide and sodium bulbs every year so. LED grow lights will be making most all high power consuming grow light systems extinct soon. They just work better based on actual plant science and are 98% efficient.
Definitely look into LED grow lights before buying any other grow light system.