tefa (textured earth, food all-year): greenhouse substitute

I started thinking about a radiator landscape because of the megalith site near the village of Carnac in France.  People have all sorts of nutty ideas about why these are here, but I'm fairly sure they were put there by Sepp Holzer's great, great, great, great, great (repeat many more times) grand pappy so he could grow citrus between the stones.  I mean, check out these pics!


Lots of thermal radiation from the earth below can shoot out between all these stones to fill the spaces between


Now that's a radiator!


One example of the many dolmen found on the site.  Apparently when no one is paying attention, local farmers will use these for sheltering sheep and chickens....stone can do it's job for just about ever.  Sepp's great, great, great, etc., grand pappy would be so proud!!!

Here's a concept drawing for a masonry array.  Site selected with a winter water table that's relatively high, though probably below the frost line so that the top of the water table isn't frozen.  Would want that brick to be dark and perhaps a bit rough to increase emissivity, although apparently cement has a pretty high emissivity so the brick cladding might not be required.

Wow!  I love the dolmen!  I have been bouncing around the idea of one for my place...for me and my animals!

I know an instance where something like this actually works to provide food all winter. And a new element not previously explored: springwater.

The instance is watercress springs, where the groundwater comes up at a constant temperature through the whole year, providing an adequate environment for the growth of watercress, speedwell, and forget-me-not even in the coldest months. I have also seen marshlands around watercress streams where sedges were green and growing in February. So, if we turn our expectations towards wetland plants, then suddenly the whole thing becomes much easier.

I wonder if chinampas amidst such spring environments, along with sun scoops, etc., can keep the soil warm enough to grow terrestrial plants. Although my observation points to watercress as the most practical winter vegetable to grow by this method.

Maieshe, I've measured our spring water as having a temperature of about 12 degrees C all year, so this would definitely have some possibilities for green vegetables. At my lattitude light becomes a limiting factor for actual growth, but things survive.