First, welcome to the grow light selector tool. If you are using your garden area to grow clones or seedlings, then you should use a fluorescent light (or two) to light your garden area. If you are using the garden area to grow plants in the vegetative stage to 14 inches tall (or less), then you will need to use 3 to 5 fluorescent lights or a small metal halide to properly light the space.
If you are using an area to grow plants in the vegetative stage larger than 14 inches tall, it is best to use a small to medium size metal halide light. High Pressure Sodium lights are also acceptable in this situation. Unfortunately, the light from a fluorescent grow light is not strong enough to support healthy plant growth beyond 14 inches from the fluorescent bulb, which makes them useful only for shorter plants.
Finally if you are growing plants in the flowering stage of plant growth, you should use a high pressure sodium light. These are just general guidelines, as I have also seen plants in the flowering stage do very well under a metal halide light. Ultimately the size of your light will depend on the size of the garden area you are trying to cover, and how large you intend to grow your plants before harvesting.
Seedlings and clones, and even small plants in the vegetative stage, will do just fine under 20-30 watts/sq foot. Larger plants in the vegetative stage will do better if given a little more... about 30-40 watts/sq foot. Plants in the flowering stage require a lot more light, and should be given 40-60 watts of light per square foot. Again, these are general guidelines that should work well for most plants that require lots of light. It is always a good idea to know the lighting requirements of the particular plants you are growing.
The first step in choosing the size of light you will need is to measure the floor space of your garden area (example: 2 feet by 4 feet= 8 sq feet). Next, multiply this by the watts per square foot you would like (example: 8 sq feet times 50 watts/sq foot= 400 watts). Break out your calculator if you need to, this is important to your indoor gardening success!
In the example above, you would need 400 watts of light to illuminate
a 2 x 4 foot garden at 50 watts/sq foot. As luck would have it, a 400
watt light is one of the standard sizes. The most commonly used grow
light sizes are...
You must choose the light that most closely fits your garden's needs. Keep in mind, a 250 watt garden will have a smaller yield. Also, I do not personally recommend using 1000 watt lights unless you are prepared to go the extra mile to keep temperatures down in your garden area. Check out this hot tip for the whole story.
If the grow light selector tool has led you to a metal halide or high pressure sodium light, there are a few system options to consider. Lets look at a few of them...
The grow light selector tool really comes in handy for this part. A
light reflector like this, that is not enclosed and not air-cooled by an
exhaust fan, sends all of its heat out into the room, (where you must
use a good exhaust fan to deal with it). If your garden area is open to
freely exchange air with a larger room, this is the only time I would
consider using this type of light.
Most of the time, however, your garden area will be fully boxed in, in order to be able to provide a dark period to force flowering. That is why I do not recommend these reflectors in general.
With the light fully enclosed and glass in the bottom, you can attach the light to an exhaust fan and control most of the heat at its source. Most of the heat will never enter your growing area. The less your airflow is obstructed, the better the cooling effect will be. Lets take a look at a few more things to consider.
A reflector with exhaust vents like this is better than a reflector with no exhaust vents. However...
when you turn the reflector over, you can see how the airflow will be slowed down by the tiny vents inside.
Even if this reflector had good, 4 inch vent holes all the way through, the airflow would still run into the bulb and be forced to flow around it (slowing the airflow).
This reflector, vented corner to corner, has the same problem.
In this two bulb system, you can see how the airflow would pass through the reflector in between the two bulbs (not blocking the airflow at all). This design is better, but there is still room for improvement.
The 6 inch vent holes in this reflector are not only large... they go all the way through, allowing a maximum airflow through the reflector.
Looking underneath, you can see how the air moves unblocked through
the reflector, past both sides of the bulb (and not right into the
bulb). This design provides the maximum, unobstructed airflow (therefore the maximum cooling benefit). This is the design that I use myself when growing in an enclosed area.
To check out some of the other stuff that I use, check out my most successful homemade hydroponic system.
The grow light selector tool would not be complete without a section on your ballast. A ballast is a heavy electrical part that comes with every grow light. The ballast uses your home electric and "bumps up" the current to run high intensity discharge lights properly.
The biggest consideration with your ballast is the extra heat it generates. Most light systems, like the example above, attach the ballast to a long cord. This allows you to place the ballast in another area outside the garden area. This is called a remote ballast. Compared to having the ballast IN the garden area, the temperature difference can be as much as 10 degrees.
This is exactly the type of light you do NOT want to get. This light reflector is wide right here because it has a built in ballast, forcing you to deal with the extra heat inside your garden. I do not recommend using this type.
Several years ago, another option became available. This is the digital ballast. A digital ballast uses computer chips to draw and produce exactly the electricity needed to run your light in a way that maximizes its light output.
A standard ballast uses a coil to do this. The coil has a cycle to control electric output. At the top of each cycle, there is a little extra energy than is needed to run the light. This extra energy is wasted each time as the cycle starts over (which is constantly).
The end result is that a light run by a digital ballast will constantly put out slightly more light, and will do it using about 1/3 less electric. For my next system, I will have a 600 watt light with a well vented reflector and a remote digital ballast.
By now you have chosen a light with the grow light selector tool. The
best lighting tips for your newly selected grow light can be found in
one of the following areas...
I suppose when you take into consideration how much money you save NOT
having to buy food at the grocery store, it is surely cheaper to grow
your own food hydroponically even with the cost of high quality
nutrients. Nevertheless, I didn't have a whole lot of money to work with
and I needed to make my efforts as affordable and effective as
possible....and in the last 24 years I HAVE learned a thing or two!
As you browse through Jason's Indoor Guide, you will notice all of the systems that I use personally are homemade systems. As I got 3 or 4 years of experience under my belt, I quickly adopted a preference to standing water systems and systems that use expanded clay pellets or lava rock, because the media is re-usable and it eliminates a huge operating expense. So once a hydroponic system is built, garden maintenance is minimal- check and adjust the nutrient solution daily, and to change it completely every 2 weeks....and the biggest operating cost is the hydroponic nutrients. (and the electric bill, lol)...
And, regarding the cost of the nutrients....I experimented for about 3 years with making different compost teas and nutrient teas, but there is still a lot of expense $$$ associated with making high quality nutrient teas....like kelp meal, liquid seaweed, rock dust, bat guano, un-Sulfured molasses, worm castings. You can eliminate a lot of this expense by becoming an expert at making high-quality colloidal humus compost, and use your properly made compost as the basis of your hydroponic nutrient solution.
Unfortunately, I have been gardening for over 24 years and I have only
just recently mastered this difficult skill....and even then, only
because I happened to find a very easy to follow, high quality technique
and decided to follow the instructions to the letter. I produced more
high quality compost in just one week than I was able to use in a whole
year! If you can master the technique, I highly recommend it. It is one of the top 3 things you can do to
increase the productivity of your food production efforts, while at the
same time decreasing the amount of effort required to grow all of your
own food, and decreasing the total cost of operating your food
And when I say decrease operating costs, I mean decrease them to almost ZERO, especially if you are producing your own nutrients...
The ultimate solution to eliminate the cost of your hydroponic nutrients: Imagine a hydroponic system that does not require you to buy any nutrients, does not require you to make your own compost, and does not require you to brew your own nutrient tea. Seriously! No cost and no effort as far as providing nutrients to your plants! Plus, at the end of the gardening cycle you harvest all of your garden vegetables, PLUS YOU HARVEST FISH from the system--->
This solution is aquaponics. If you are serious about producing all of your own food and being self-sufficient, this is the ultimate solution for reducing expenses (as much as possible), reducing the total amount of work required, and maximizing the productivity of your gardening efforts. I have been gardening for over 24 years, and it is the perfect food production solution in my opinion.
Besides mastering how to make high quality compost, learning aquaponics is one of the top 3 things you can do to increase your garden productivity, reduce your total costs, and reduce your total work. The product that I learned from is called Aquaponics4you. With all of my hydroponic gardening experience, the first time I came across the Aquaponics4you product I knew immediately that it was something very special! Place an aquaponics system outdoors and use the sun instead of grow lights, and you have reduced every garden expense to nearly ZERO!
The Same System/ 10 Weeks Later!