Your Garden Exhaust Fan Setup

Your exhaust fan setup is one of the most important elements of your indoor garden. Controlling hot temperatures is critical to having success. For a better idea of what kind of light you should be using in your garden, check out the light selector tool, and to figure out what size and type of exhaust fan would be best for your situation, check out the exhaust fan calculator.  Just like a good garden design, a good exhaust fan setup can be broken down into a few easy steps. The basic idea is to...

  1. make the run as short as possible

  2. make as few turns as possible

  3. pull in fresh, cool air from the bottom

  4. exhaust hot, used air from the top

The Exhaust Run

Easy enough...determine where you will exhaust your hot air, then design your garden so the grow light is conveniently located to the point of exhaust. If the distance is greater than 20 feet, make sure the fan in your setup can handle the extra strain. Try to make the run straight from your lights to the exhaust point, with as few turns as possible.

Airflow in the Garden

Exhaust hot air from the top, allow cool air into the garden from the bottom

Since hot air rises, you will be removing much more heat from the garden by starting your exhaust near the ceiling of your garden area. This creates a vacuum that naturally pulls cooler, fresh air into the garden from vents located close to the floor. Use an oscillating fan on the floor to keep the cooler, fresh air moving through the plants and toward the exhaust.

Fans are much more efficient at PULLING air then they are at PUSHING air. With this in mind, the exhaust fan is usually placed right at the point of exhaust. From there it will pull air through your exhaust fan setup (through the light reflector) and out of the garden area.

Some Exhaust Fan Setup Examples

a closet-type area, with the door left open whenever the grow lights are on

If your garden is in a tight space, like this example, you may need to mount your exhaust fan outside the garden area. Keeping your ballast outside the garden area will also help keep the temperature down inside the garden. Any garden in a small space will need a good source of cool air. The front door of a closet can be left open, if the temperature of the air in the larger room is cool enough. Otherwise air conditioning will have to be pumped into the garden, either directly or by fans and ducts.

ideal setup for a small grow room

This is an ideal exhaust run. The intake on the exhaust system (the carbon filter) is up high to catch the hottest air. The exhaust run is straight (no turns) and short, and removes much of the heat from the light before it ever enters the grow room. The grow light needs to be run with it's pane of glass in, otherwise the carbon filter will not benefit from the airflow. If you do not have a carbon filter, simply leave it out of the picture.

an acceptable setup for a small grow room

If you cannot attach your carbon filter to the ceiling, try to get it as high up in the garden area as possible. Milk crates might come in handy for this. The exhaust setup in this example should be fine. One side note...the examples here are all shown with centrifugal fans. With no carbon filter, these examples would work fine with squirrel cage fans. These fans are covered in more detail on my garden exhaust fans page.

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(10 week update below)

Find out the cheapest and easiest ways to garden productively in this article.

Hi everyone, Jason from Jason's Indoor Guide here. When I got started with hydroponic gardening more than 24 years ago, my first garden used rockwool cubes and B.C. Nutrients....and I remember thinking to myself yeah, sure, there may be a lot of advantages to gardening with hydroponics, for example there are very few pest problems, therefore very little pest control, no weeding, no plowing or tilling the soil, no soil testing or having to add things into the garden soil, no watering the garden....but for someone who just wants to grow their own vegetables and have more control over their food supply and the quality of the food that they eat, the cost of constantly having to buy grow media and hydroponic nutrients makes this an expensive hobby for most people...

Epic Nutrient Change

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)...

Homemade Cloner

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 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 production system.

And when I say decrease operating costs, I mean decrease them to almost ZERO, especially if you are producing your own nutrients...

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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--->


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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.

Produce garnden vegetables AND fish together. Eliminate fertilizer costs!

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!

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