Lighting: Back to the Basics Vol 1

The Webster’s Dictionary defines “Man” as follows:
Man (n): (1) Opposite of woman (2) Male member of the human race, totally incapable of reading instructions or asking for help.
What women pass off as ignorance leading into arrogance is in reality an insatiable desire to jump headlong into an activity as fast as possible. As men we would always rather “Do” then “Learn”. Besides, after we are done shoveling the family cat into a garbage bag after a freak electrical accident, we can make up a perfectly good lie over beers at the pub later to make us look better. Research is for suckers.
So roll up your sleeves, and check the wallet. In the next few issues, we are going to show you the basics of setting up your own hydroponic garden with as little muss and fuss as possible. Strictly meat and potatoes stuff here; function over fashion. Once you harvest your first crop, you can do a little more digging and fine-tuning. For now, lets just get you up and running with just enough knowledge to keep you from having your home declared a disaster area.
Undeniably with your first garden, lighting will be your biggest initial cost. You will notice the word “initial” there. Buying your ballast(s), bulb(s), reflector(s) and wiring will earn you more air miles than you probably would like, but the overall cost of operating the lighting will be much less than you may think. But, let’s back up a bit. Incandescent Bulbs are the standard bulbs you may be familiar with operating in your own home. A natural by-product of incandescent lighting is heat energy. If you have ever mistakenly tried to unscrew a burnt out light bulb too quickly after it burned out you know what I mean. That amount of heat build up makes the incandescent light bulb unsuitable for hydroponic gardening, thus leaving you with two options: Fluorescent Lighting and High Intensity Discharge Lighting.
Fluorescent lighting is great because it is a cool light. The process by which fluorescent bulbs illuminate creates very little heat energy, thus is far superior to incandescent bulbs. However, there is a trade off. The soft, cool light of a fluorescent bulb is only effective when placed approximately 8” to 10” from the plant itself, so once your crop’s stalks become a foot or so long, this lighting becomes too inefficient. The plant’s lower leaves do not readily receive enough light, so photosynthesis suffers. In short, it would be like sending your plants to Idaho for a summer vacation. Sure, they would come home with some great new potato jokes, but not much of a tan. Fluorescents are most effective in the sprouting stage of your plants, before they begin their vegetative cycle. Whether you are raising your plants from cuttings or seeds, setting your initial garden up with fluorescents is a great way to go. Think of it as hydroponic elementary school…. where your plants go before they know everything, and ask to borrow the car.
High Intensity Discharge Lighting (or HID for lazy people that like acronyms) has become the preferred choice for hydroponic gardeners over the past 20 years. They produce an incredible amount of light energy for a reasonably low amount of power consumption, without the severe heat build up common to incandescent bulbs. Two of the most popular forms of HID Lighting are Metal Halide (MH) and High Pressure Sodium (Yup, you guessed it…HPS).
The main difference between these two bulbs, at least the difference that is most important to you the grower, is what part of the light spectrum their output focuses on. Metal Halide is reasonably balanced, but focuses primarily on the blue-white end of the spectrum, while High Pressure Sodium focuses primarily on the red/orange end of the spectrum. Both bulbs are great for every developmental stage of your plants, but your plants may exhibit accelerated growth during the stage favouring the focus of the spectrum available. MH bulbs are generally more balanced than HPS bulbs, and your plants may flourish during the vegetative stage due to the extra blue/white light spectrum available. If it helps to have a comparison, the light offered by a Metal Halide lamp could be compared to the tropical sun. Metal Halide bulbs are available in 172, 250, 400 and 1000-watt sizes.
HPS bulbs, offering more concentrated red/orange spectrum light, will make your plants flourish during the flowering stage. However, because of their focus, your plants may appear stretched, or leggy, during the vegetative stage as the stalk grows vertically searching for more blue/white spectrum light. Because of this, High Pressure Sodium lamps are best used as a replacement for Metal Halide lamps once your plants flower, or in a situation where they are supplementing natural sunlight, such as in a greenhouse. While their light output is fairly range specific, HPS bulbs are also the most efficient bulbs available. They produce the most lumens per watt, roughly ten to fifteen percent more than a Metal Halide bulb of comparable wattage. High Pressure Sodium bulbs are available in 150, 250, 400, 600 and 1000-watt sizes.
If you would like to give your plants that extra kick in the ass during the flowering stage, you might want to consider a Conversion Bulb. Setting up an HID lighting system isn’t as simple as screwing in a light bulb. How many hydroponic gardeners does it take to screw in a light bulb? Just two, but I am still trying to figure out how they got in there.
HID light bulbs require ballasts to handle the conversion of electrical energy. Conversion Bulbs are HPS bulbs specifically made to work with MH ballasts. So, when your plants reach their flowering stage, all you have to do is to swap out your bulb. This is much easier on the pocketbook, and takes much less set up time. Let’s face it; we are all cheap and lazy. One thing to keep in mind though: Conversion Bulbs are only available in 250, 400 and 1000-watt sizes.
There are four main components to your lighting system: Wiring, ballast, bulb and reflector. The set up is reasonably simple, but so is starting a fire. So, just to save yourself some peace of mind, have your lighting system rated by an electrician.
When setting up your own lighting system for your garden, you are trying to make the most efficient use of your light energy, while minimizing the running cost. A reflector will help direct and diffuse your light, concentrating it where it is most needed. Using a reflective material, or even a white paint on the walls of your garden will also up the efficiency. As a general rule of thumb, most gardeners try to output 25 watts of light per square foot of garden space. If your manufactured light is supplemented by natural sunlight, or if you are growing leafy vegetables such as lettuce, you may require less wattage. Ask the nice person at your local hydroponics store what is the best solution for you; just try not to call them between 3am and 5am. I tried it and believe me they don’t like it. Light Movers are another method of getting more bang for your buck. They come in a variety of styles, but their basic premise is the same. They simulate a natural horizon by slowly moving your light either in a circle or straight line over your plants, thus increasing their effective range. Another benefit of mobile light, is that since its perspective is always changing, it can penetrate the plant canopy more efficiently. This in turn offers more light to the surface of your plant’s lower leaves, which makes photosynthesis more efficient.
To make it easier on you, measure the size of your grow area before you buy your bulb or bulbs. This is a general breakdown for your lighting needs. However, it is only an outline. The use of light movers, reflectors and reflective materials on your walls such as mylar can greatly increase your lighting efficiency.
150/160/175 watts 2' x 2' area
250/270 watts 3' x 3' area
400/430 watts 4' x 4' area
600 watts 6' x 6' area
1000 watts 8' x 8' area

As I mentioned earlier, you may be surprised by how little your energy consumption goes up due to your lighting system. You will definitely notice the difference, but it may not be as dire as you originally suspected. Either contact your power company, or check your most recent bill, to find out the current cost for kilowatt-hours. Depending on your crop, you will probably either be running a twelve or eighteen hour light cycle. To find the consumption of your bulb, take its wattage and divide by 1000. This will give you its kilowatt rating. Then multiply this number by the power company’s cost per kilowatt hour, then multiply this number by the amount of hours the lamp will be operating in a day. This will give you in dollars and cents, the cost of operating your bulb for one day. Example: You are operating a 400 watt Metal Halide Bulb. Dividing 400 by 1000 leaves us with .4. That is our kilowatt rating. To keep this example simple, we will say that our power company charges us 10 cents per kilowatt-hour. So, to find out your cost per hour for your bulb, multiply the kilowatt rating (.4) by the cost per kilowatt hour (.10). This gives us our hourly operation cost, which is $.04. Our garden is operating on an 18-hour light cycle, so I multiply the hourly cost (.04) by the amount of hours it will be operating in a day (18). This gives us our daily operating cost, which is $.72. If I multiply this by 30, we find that the average cost of running my 400-watt Metal Halide bulb for a month will be $21.60. This is less than the cost of one of Oprah’s mid-morning Sausage McMuffin binges
New technology and new ideas are always popping up to help you save time and money on your home garden. Hopefully, this “get familiar with lighting quick” guide will help get you started on your road to “green-thumb-dom” in the hydroponics world. However, once you finally decide to read the set of instructions, give me a call. I still have a drawer-full of extra pieces.