Hydroponic Nutrients and the Autopot System
By: Joe Ruth
This article is written to provide the novice gardener with some basic lessons learned in starting a hydroponic garden. Five years ago I wanted to grow a few tomatoes without excavating my backyard. I concluded a hydroponic garden was the answer as it would provide a means to grow tomatoes without a lot of hassle, maintenance and expense. With that as a back drop, here are the issues and lessons learned I confronted.
There are numerous hydroponic systems on the market. Since I was not a commercial operation, I wanted a system that did not require pumps and electricity. I figured those just added additional costs and maintenance. I ultimately decided on the Autopot.
The autopot system does not require any pumps or electricity. The system basically consists of a tank, plant pots, trey that holds the plant pots, a smart valve, and interconnecting plumbing. The system is gravity fed requiring no pumps or electricity. I have five sets of two that grow ten tomato plants, such as Better Boy, Big Boy, Cherry tomatoes to name a few.
The hydroponic nutrients tank I use is a 55-gallon used pickle barrel, I purchased for $12.00 at the local hardware store. The smart valve is the key to the autopot sytem. The smart valve shuts the flow of nutrients off at the high level and dose not open to fill until the nutrient level has almost depleted in the trey. This way optimum growing conditions occur as the valve simulates periods between rain fall, as opposed to maintaining a constant full level. For a brief period, when the nutrients are at a low point, the roots are exposed to air (a good thing).
The hydroponics nutrient tank is connected to the smart valve by plastic tubing and valves. I also have a valve on the bitter end to periodically flush the lines. I use one half inch tubing with a punch in nipple fitting that reduces to a smaller size hose for connection to the smart valve. Even though the nipple is punched into the one half inch tubing, it does not leak and super easy to assemble.
One of your biggest recurring expenses is the cost of nutrients. When I first started, I was under the mistaken assumption that I had to use some type of nutrient that had the word hydroponic in front of it. Every time I turned around I was buying more nutrients. If you only take away one lesson learned from this article, remember, there is an "inexpensive alternative called water soluble fertilizer." Emphasis added.
I learned of water soluble fertilizer while visiting the local University Agricultural Extension Service in my area. They did research on hydroponic systems. There tomato plants were like Jack and the Bean Stalk. The agent told me what to buy and what mixture to use.
I purchased for $30.00 a 25-pound bag of water soluble fertilizer made by PRO-SOL in Alabama. Keep in mind there are other manufacturers of water soluble fertilizer. You need to read the ingredients and determine if any supplemental fertilizer is needed, such as Calcium Nitrate, Potassium Nitrate or Epson Salt. With PRO-SOL, I had no loss in production or quality. Twenty pounds makes 3,000 gallons. Since I wanted to make 50-gallons at a time for my nutrient tank, I used 5.3 ounces. Needless to say, I haven’t had to buy nutrients for the last 3-years and have enough for a couple of more years. A big cost saving.
You need to supplement the 3-15-27 with Calcium Nitrate 15.5-0-0+19CA. You use 4 to 8 ounces during the, grow and start of Flower stages and 8 to 16 ounces during the flower and fruit stages. Using too much Nitrogen in the grow stage causes rapid growth and compromise of the stem joint areas presenting a place for disease to enter the plant. Your tomato plants must grow and develop at the proper rate (not too fast or too slow).
Key Point: Using a one gallon bucket, dissolve the 3-15-27 in warm water. Using a separate one gallon bucket dissolve the Calcium Nitrate in warm water. The point is, do not dissolve in the same bucket. It will turn cloudy, keep separate while dissolving. Once dissolved, dump both mixtures into a 50-gallon tank around the 40-gallon fill point while filling. Top to 50-gallons, stir and the hydroponic nutrient solution is ready for use.
Last, the median that can be used in an autopot varies. I started with a 60% coco husk and 40% perlite mixture. The mixture worked good for tomatoes but a little pricey. The coco husk acts as a wick and the perlite provides space and oxygen for the roots when the nutrient level drops. I have also mixed perlite with peat moss with equal success.
In the autopot system, the plant pots use a disposable coffee like filter in the bottom of the pot to keep the roots in. If the roots grow out of the bottom of the pot they will foul the smart valve. The autopot initially comes with a filter, however, after the first year you need a new filter. As a work around, I use the black plastic landscaper weed control that has little holes. I line the entire pot.
I sincerely hope the information in this article was helpful and provided some tips on cost savings and alternatives in using and purchasing hydroponic supplies and systems.
About the Author: Joe Ruth This website is a link to the world wide web for the novice, providing cost saving ideas and lessons learned. Hydroponic Nutrients is a link discussing hydroponic nutrient alternatives such as water soluble fertilizer. Autopot is discussed.