We will start with a standard Vegetable Greenhouse (groentetonnel) early. This greenhouse will be the home of our Aquaponics system and our tropical fruit trees. We house these indoors to limit exposure to the elements such as cold wind, frost, hail and cold rain.
To start we will build a standard size greenhouse which we buy secondhand. We will buy a standard size 30m x 10m x 4m greenhouse for full tractor access.
We will then convert this greenhouse into a closed greenhouse to minimize water loss. This way an intensive greenhouse can be run with rainwater runoff off the roof only in areas with only 200mm per year rainfall. (300m2 x 0.5L/day = 60m2 per year = 200mm rain per year). We’ll need six 10m2 water tanks if we really want to demonstrate this, else it will be much cheaper to use 60m2 from the borehole…)
See the paper: “Closed Greenhouses, a Tool for Productive Water and Land Management.pdf” by Martin Buchholz and http://watergy.de/geschlossene-gewaechshaeuser/
In winter our greenhouse will be heated by compost heaps inside, distributed in the corners and along the edges where the cold would seep in. We can also cover the inside with bubble wrap if needed.
The aquaponics tanks and high carbon soil serve as heat sink.
Later we want to convert to glass construction in order to show that this can be done without plastic.
- 300m2 costs 70 000,- in SA. Excluding transport and
- Import V
Compost in the corners – keep the chicken here at night in the winter – chicken are great room heaters (Mollison)
We should also include a large water storage – perhaps a duck pond – perhaps a natural swimming pool – as heat storage for the greenhouse.
In order to help limit our workload and save cash we can build our own tools (https://www.opensourceecology.org/) , use opensource farm planning software http://farmos.org/ and start farming with robots https://farm.bot/.
The main ways to heat your greenhouse without electricity are: natural thermal masses such as water barrels or dark stones, as well as compost and even chickens. Depending on the size & indoor temperature needed, these methods–and good insulation–can heat a greenhouse.