self sufficient life

We’re back!

Yes, I know, we wanted to live off-grid, but the property we bought is a little too far off. Now we have finally found an internet provider that can supply us with a decent internet connection, so we’re back online!

These past 2 months have been very eventful, but we are about settled now. The first 4000 liter fish tank has been set up inside the greenhouse. For now it houses goldfish. We’ll have to see how temperatures develop in the greenhouse throughout the winter. I will probably build a shed around the fish tank and connected grow bed and equip it with a grow light to be able to grow some veggies this winter.

Sorry, no pictures at the moment, as the USB cable for the camera is still in one of the unpacked moving boxes…

Free Fish Food

Daphnia (a.k.a. water fleas) can be bought at most aquarium shops, but what if you could get them for free? These tiny crustaceans are really easy to breed. In the summer months you can simply put a bucket filled with old aquarium water in a sunny place and they will have enough food to thrive and you will have a constant supply of free fish food.

I filled a 250 liter rainwater barrel with aquarium water and put some fish food in there every few days until I had a nice algae bloom.

I went to the aquarium store quite a few times, but each time they where out of life daphnia, I used too see them there every time, but now that I needed them they didn’t have any… typical…

Eventually I managed to buy a small bag. I put them in the green water and after only two weeks the water was crystal clear and swarming with daphnia. Every day I can scoop some out to feed my fish but the supply seems endless.

During winter the barrel froze over and I thought that the water fleas had probably all died, but to my surprise they continued breeding when spring arrived.

If you want to have live fish food during the winter as well, you can set up a culture vessel inside, but you will probably have to feed them.

Free food production in your backyard

Summer is really starting now! The last couple of days we’ve had 23 – 25C temperatures and the forecast for the next week is the same. While our friends from down-under are getting ready for winter, we can start growing all sorts of yummy things in the garden.

I thought I’ll use the long weekend to set up a little half barrel aquaponics system. I still had one of those blue barrels laying around, so I went ahead and cut it in half to create two grow beds. After filling the grow beds with washed gravel and filling them with water the troubles started: I was using a loop siphon to do the ebb and flow in the barrel, but the loop just didn’t work like it should. When filling the barrel, the siphon should kick in at a set level and empty the barrel again, giving the plant roots access to oxygen rich air. After the barrel has been emptied the siphon should break and the barrel should slowly fill up with water again.

My siphon either wouldn’t kick in correctly, leaving the barrel flooded, or it wouldn’t break, leaving the barrel empty at all times. Some more tweaking is necessary for my barrelponics to work. Since I don’t have to go to work today, I’ll have all day to try to get this working.

Ferro cement

If I want to set up a big aquaponics system I need some big water tanks and grow beds. Looking at various suitable tanks, they all had one thing in common: a very high price tag! Living self-sufficient means doing a lot of DIY, so I went on searching for a low cost alternative to use as tanks. I quickly stumbled upon ferro cement, which is basically a 3:1 sand and cement mixture with chicken wire used as rebar.

The strength of the chicken wire concrete is amazing and the uses are endless! Entire houses are being build with ferro cement and due to how these structures are build, you can go nuts and make your house a piece of art. Once finished, your structure will be truly low maintenance and it can withstand earthquakes and hurricanes.

I’m not building a house but fish tanks and grow beds both need to be sufficiently strong to be able to hold their contents and be water tight. The ferro cement is water tight and is used to build water containers around the globe. Because of its low cost it is used a lot in developing countries. The biggest saving comes from the incredible strength of the material, with the need of much thinner walls, compared to rebar concrete, you will only have a fraction of the material costs.

Aquaponics

My aquariums have a healthy balance of fish and plants. The water is crystal clear and the plants are thriving. I don’t have to do any water changes to keep all levels in the optimum range, the only thing I have to do is top up the water every other week to compensate for evaporation. A well balanced system like this is easy to create and maintain in an aquarium. It takes some experimenting, but once you get the hang of it the maintenance is next to nothing and you can just sit back and enjoy watching the fish.

Intensive fish farming is a different ball game. If you want to make a profit you have to put a lot more fish in your water. The water gets polluted by the excrements produced by the fish, making the water toxic for them. Bacteria that live in a biological filter can convert the highly toxic ammonia into nitrite and nitrite into nitrate. High concentrations of nitrate are still bad for your fish, but they are an excellent nutrition for plants!

You could use the nitrate rich water to fertilize the soil in your vegetable garden and replenish the fish tank with clean water. This would however require a lot of fresh water and a big part of the nitrates would sink deep into the soil, beyond the reach of your plants roots.

The solution here would be hydroponics. In a hydroponics system you grow plants in water instead of soil. The water in a hydroponics setup is enriched with nutrients that the plant roots normally extract from the earth. Small crops like salad and herbs can be grown on a raft that floats on the water and has holes in it for the roots to reach the nutrient rich water. Bigger crops like tomato plants need some coarse gravel or rock wool for support. This grow medium is located in a tub that is flooded with the nutrient enriched water. After the growing plants have extracted the nutrients from the water it has to be enriched again.

Hook the fish farm up to the hydroponics and you have an aquaponics system. The fish provide fertilizer for the plants and the plants clean the water for the fish. The balance in an aquaponics system is much like in my aquariums but both the fish and plant density are much higher. As long as you make sure that this balance is maintained, you can make the aquaponics system as big or as small as you want, ranging from one small fish and one plant to a pond with thousands of fish and an acre sized greenhouse.

A big commercial system isn’t for everyone, but you can have a small aquaponics system in your garden or kitchen made out of items you probably already have laying in your garage or shed. Put a little work into it and you can enjoy home grown fresh herbs and vegetables, without the pesticides!

Looking for information on the subject, I stumbled upon the Backyard Aquaponics Forum, which turned out to be a very friendly community of people with a great deal of knowledge and experience in this field.

Fish farming

I have enjoyed keeping fish for a long time. Looking for something that could make some money in the winter time, when crops don’t grow on the land, fish farming sounds like a good option. There are several species of fish that could be breed economically in our central European region. I would probably keep carp, tench and zander.

Fish farming can be done in two ways: extensive (pond) or intensive (closed-circulation) Extensive aquaculture requires very big ponds that are lightly stocked. You will need about 15 square meters (160 square feet) of pond surface area for each carp. The total water volume doesn’t really matter since the food supply in the pond is following the natural food chain, starting with the algae growing in the sunlight hitting the pond, making the surface area of the pond the limiting factor for how much fish you can grow.

With intensive aquaculture you can keep as many fish as you can fit in your body of water, as long as you make sure that the water is clean and that there is enough oxygen and food available for the fish. To keep the water clean and oxygenated a good filtering system is needed and a set of pumps to move the water through the filters.

Since a patch of land that is big enough for extensive fish farming would just cost too much, I will work with a closed-circulation system. I will have to look into the total cost of different systems. The cheapest option would probably be digging a big pond, but the fish production would be limited in the winter time. A more profitable system would consist of indoor ponds, making it possible to achieve maximum growth year round.