Sustainable food

Aquaponics and the Subterranean Greenhouse 

To grow efficiently we need a greater control.

In Coed Glannant, some things work well for us and some things don't and therefore we have to think outside of the box a little.

Controlled growing would be best done in a greenhouse but the woodland doesn't suit a traditional greenhouse and there are some flaws with greenhouses too.

Although light enters the sides of a greenhouse, most crops grow on the benches so this isn't beneficial; but, the extra glazed areas allow excess heat to build in the summer and radiate the winter cold in.

To reduce our visual and physical impact in the woodland, our greenhouse will be subterranean and will be sunk into the ground by approximately 1 metre. This will allow the thermal mass of the ground to stabilise the temperature keeping the air slightly cooler in the summer and warmer in the winter.

In the greenhouse we plan to create an Aquaponic system.

Aquaponics is not unlike hydroponics but rather than adding nutrients to the water flowing through the growing medium, fish waste is used instead.

Finding the balance is the key, too many fish and the plants won't be able to filter out the waste quick enough, to few fish and there wont be enough nutrients to feed the plants.

In the winter, the plant growth will be reduced through lack of light and thus the quantity of fish should be reduced too so a winter holding pond will be needed.

Large fish tanks in the greenhouse not only hold the fish (that feed the plants) but the thermal mass of the water also helps to regulate and stabilise the green house temperature.

In the depths of winter, the greenhouse will be heated with a rocket mass heater. The design and use of the rocket mass stove is detailed under a separate tab as it is the same style as the one used in the Earth Bag house.