I am exploring the use of large rocks strategically spread throughout the garden to aide in the thawing process in spring. In the warm months, and in the winter when the rocks aren’t covered in snow, rocks buffer the diurnal temperature swings. That is to say they make the micro-climate around them a more constant temperature throughout the night and day.
They do this by absorbing heat throughout the day and slowly releasing it at night. This is an example of using the concept of thermal mass in the garden. Sepp Holzer successfully uses this technique to grow lemons and limes in the Austrian Alps.
Something that I find interesting and that I have been looking at in rock outcroppings and also cemeteries is how the vertical face of a rock, if facing south (towards the sun in our northern hemisphere), induces melt faster by providing a dark energy absorbent mass. Once the white of the snow is gone the ground warms much more rapidly than it would have in a flat garden space.
Something that would be worth experimenting with a little is whether a large rock with the majority of its mass buried (picture an iceberg, with the majority of the mass underwater) will act as a geothermal syphon and buffer the temperatures of the earth below and the weather above. Essentially, if this were the case, we would not only be getting energy from the sun and storage from the rock, but we would also be pulling energy up in the cold months and pushing it down in the warm parts of the year with the rock acting as a conduit.
Additionally, rocks and gravel are the primary source of minerals in the soil and break down as your plants need them.
These are just a few things to consider when you finally dig that clunker out of your vegetable beds and don’t know what to do with it.
-Troy