Aeroponics Pump and Timer

by Danny Cook
(Athens, AL)

I'm in the process of installing a greenhouse (30 x 72) in which to grow vegetables for sale (tomatoes, cucumbers, and squash), particularly in the winter months. My first choice would be to go with Aquaponics, and have spent time at an aquaponics farm with which Auburn University is helping. However, I've determined that aeroponics would be better for me to get my feet wet, and then move into aquaponics.

So.....I'm going to build your homemade aeroponic system as a trial and need to know what pump and timer you suggest, along with the nutrients you suggest. I've read the optimum droplet size is 50 Micron. In your testing do you see this as critical? How big do you think the droplet size is with a 1/16th hole in the PVC? Thank you, Danny Cook.

Answer: Danny- The particular brand of pump you use for your aeroponic system is really irrelevant, as long as it is capable of producing the 40-60 psi necessary for pushing the nutrient solution through your system. It is also very important to use a manifold in a system like this, otherwise you will have 1/16th inch holes (your "spray nozzles") that do not get the proper amount of fluid pressure, and therefore do not spray properly.

There are many different manufacturers of suitable pumps for this type of application. One excellent choice is the TNC water pump (right), capable of providing adequate water pressure for up to 60 spray sites (and designed specifically for aeroponic systems). Good aeroponic pumps are always a little on the expensive side....this one costs nearly $200, and is available at Alternative Garden Supply. If you want a more affordable option, you will be able to find one with a little research. Simply find a pump with the same or very similar specs and you will probably be OK.

A good friend of mine bought one of these expensive pumps for a homemade hydroponic system, and burned it out the first time he ran it. He hadn't cleaned the system out very well before his trial run, and there were still many small PVC shavings in the tubes from the manufacturing process. If he had used an in-line filter in the system before the pump, it would have saved him $200! So, be sure to use one....and be sure your in-line filter is capable of working with pressures of 40-60 psi before you purchase it.

The most critical factor in aeroponics is the air. No nutrient absorption occurs except in the presence of Oxygen. The more Oxygen present in the root zone, the more hydroponic nutrients can be absorbed. This is part of the reason aeroponics produces such fast growth rates. The droplet size is largely irrelevant for a few reasons. First, any size water droplet has an extremely large surface area compared to the water surface area of any other hydroponic system (such as NFT, DWC, or even drip systems).

But that is not even the most compelling reason. In any aeroponic system, the roots of the plants hang in the air. The standard manufacture of aeroponic systems includes a pump timer that cycles one minute on, and four minutes off. This is known as a recycling timer. So, no matter what droplet size you end up producing, it is only relevant for one second (from the time the droplet exits the spray nozzle to the moment it impacts the roots, and is no longer a droplet).

After that point, all aeroponic systems are pretty much created equal. The roots hang in plain air for four minutes, coated with a thin layer of nutrient solution with maximum exposure to the Oxygen surrounding them. The benefit of having a particular droplet size for that one second (literally even less than one second) is very debatable....and even if there is some tiny benefit, it is only very, very small compared to all of the other considerations.

I cannot even guess at the micron size of the water droplets produced by this aeroponic system, but I firmly believe the point is moot. The droplets could be 200 microns and it would still make very little difference in the performance of the system, or in your end results. Mostly, this kind of talk is just advertising and marketing.

Finally, as with your choice of pump, your choice of nutrients is largely irrelevant. I have yet to come across a set of hydroponic nutrients that is not complete (providing all primary, secondary, and micro-nutrients), or not customizable (the amounts of N, P, and K can be adjusted in the formula to accommodate different crop types, and the strength of the nutrient solution can be controlled by simply adding more or less nutrients to the mix).

The most important thing is that you know what the specific nutritional requirements are for the crops you are trying to grow. This is especially important if you are growing two or more different crops together in the same aeroponic system. The other important thing is that you know how to maintain your nutrient solution properly. Personally, I have always liked B.C. Nutrients very much....the nutrients are particulate free, mixing them up properly is very easy to do, and the pH is very stable once they are in solution. I hope this helps you out Danny, and Happy Growing!

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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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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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