A Green Way to Begin Aquaponic Gardening
Last week began pond building season. This is the time between normal gardening activities and fall clean up of leaves. We are fast approaching the end of another great year growing plants. So, it is fitting that it should also be the perfect time to begin growing for next season.
Water cress is one of the very earliest vegetables. It is often large enough to begin picking by the end of March. Water cress begins sprouting sometimes in the fall. More begins sprouting late winter often when heavy frost still happens frequently. It grows best in rocky creek beds where the cold winter stream flushes it frequently during the winter. It really loves this harsh time of the year. I like to look for it in Bloomington when my dog and I walk around a city park that has a stream through the middle. I know that spring is just around the corner when I notice the rapid growth. It has flowered and gone to seed as I am preparing my regular gardens for planting in the spring.
Aquaponic gardening is quickly becoming more than a fad. More fish found in grocery stores is coming from new fish farmers. Growing fish in a controlled environment means that these new business men can grow more fish in a smaller area more quickly. Fewer resources like boats and fuel to power the boats are required. In the beginning these fish farms needed to be near a large body of water such as a large river or the ocean. Frequent changes of the water were necessary to reduce the buildup of waste organics produced by the fish. It was soon discovered that it was possible to filter the fish’s water through a hydroponic garden to remove their waste and return clean water. These closed cycle growing systems use less energy and produce more food. Farmers found they could use this system to grow both fish and vegetable crops.
Introducing beneficial bacteria as well as worms to growing media quickly breaks down fish waste. The only problem is that not all plants can thrive on the relatively low amount of food from the decaying waste produced this way. That is ok. There are plenty of plants such as lettuce and watercress that do not require a heavy nutrient concentration to flourish. Fish are not a required component of my system today. My ponds are full of frogs and tadpoles all season. They provide enough animal waste to grow my water cress.
Materials For the Project
There is an easy way to start as an aquaponic gardener. And, it is a really green method too. I save old Styrofoam inserts used to protect something I bought. These should be large pieces with few holes. Because Styrofoam is not a recyclable material I save large pieces like this with the idea of using them in some way. This is the perfect way. I don’t try to color my Styrofoam. It will discolor and some moss will grow on it over time. To be honest, I haven’t experimented with changing the color. Let me encourage you to post a comment if you know any good natural ways to color these.
In addition to a large Styrofoam planter, you will need a light weight plant growing media filler. I had wanted my new water planter to have some red stone in it. I was going to use a modern product called GrowStone. This is a man made recycled glass product. I like to think of it as man-made perlite. It is made in a similar way. The glass is heated to a really high temperature. The molten glass expands and puffs up. This hydroponic growing media is heavier than perlite yet quite a bit lighter than unglazed clay products many hydroponic gardeners like to use. Before I could get to a hydroponic store, I saw some lava rock in Lowes’ when I was getting a new chain saw blade. I liked the look of it. It is a heavier product than I wanted to use.
You will also need something to fill in the cracks of the larger stones. Perlite works very well because it so light. In my case, I used some vermiculite. It is heavier. I wanted the yellow tan color to contrast with the red stone. I think some coir fiber is also a good choice. It is light weight. It holds up well when wet. Coir fiber lasts a long time.
I also had to find a way to cover the hole in the bottom of my Styrofoam. You will probably have this challenge as well. I like to use an old t shirt. It lets the water in freely yet keeps the small particles from washing out. In my picture you will see I use a small plastic saucer tray to wedge an old piece of cloth in place. The small tray provided extra support for the opening in the Styrofoam. It spans most of the hole to keep the large rock from pushing out.
Building Your Floating Container
There is not much to my design. My Styrofoam is about 18 inches long and about 12 wide and a bit over 3 inches deep. I marked the edge of the tray with a black marker about halfway on the deep edge. I did this because I like to make sure that I don’t overload my tray. I want about half of my tray submerged and half above the water. Rain, growing plants or even the frog or two that like to sit on top of these floating rest islands will add extra weight. If there is not enough buoyancy it will sink. That is why you will want to build most of this right in the water. You will want to watch your mark closely.
I recommend putting the large rock pieces in first. Your container should have most of these as the filler media. Use the perlite to fill in cracks. This lets you build the height of your tray up higher to give more dimension and interest too. The little bit of soil is only there to hold the seed in place. Too much soil would inhibit oxygen to the roots. It isn’t needed by the plant either. The plant will freely grasp and work between the cracks of the stone and be perfectly happy.
Keep an eye on each of the four sides of your tray. It will be obvious where you should add more stone or take it away. If a corner is dipping lower than the others than it is heavy. I like to put a hill somewhere in the container. Then I add stone in other areas to balance out the hill as well as how the container sits in the water. When I have what I want and the tray is still higher than the black mark, I dust with the perlite or vermiculite or coir fiber.
It is best to sprinkle your seed sparsely on top of the growing media. I sprinkle a bit of seed in the fall and then I sprinkle a bit more in the spring. I have tried starting the seed first and transplanting them. The seedlings are really delicate. I have transplanted lettuce with better success than with watercress. I let my watercress go to seed. The old season plants leaves seed for the next. I only have to drop some seed those first two times. Sometimes I transplant a small seedling from an existing tray if I forget to restock my seed.
Do not leave these new floating gardens in the pond if you live in an area that freezes. The Styrofoam is too delicate for the pressures produced by the formation of ice. Simply take it out just before the water freezes. I leave them right next to the pond. I can drop them in or pull them out easily. Remember that the small watercress that is overwintering still needs to be watered. At the risk of one of your neighbors calling Bellevue, you will need to water them if the weather is above freezing. Don’t let them dry out.
I like the look of this new aquaponic container garden I made today. The combination of the lava rock and vermiculite were too heavy even though they look great together. I don’t like how low the Styrofoam is sitting in the water. I have two options. The first is to remove some of the vermiculite or lava rocks. I’m voting instead for option two. This is to use some more scrap Styrofoam on the bottom to provide extra lifting. Yes, that is what I will do. I think I will watch an episode of The Red Green Show to get some inspiration first.