Thursday, 9 February 2012

Permaculture in Iceland: preventing soil from freezing

Well, that might sound impossible, but actually I learnt something since last year of growing a garden in Iceland. I made several beds in our garden, and I notice that one of them was particularly not frozen as of now, mid February.

The winter was very harsh in December and January, it became cold very suddently, and soon we had two months with temperatures always well below freezing and snow up to 1 meter high. February is now however remarkably warm, as it has been raining a lot. The snow is nearly gone but most of the soil remains deeply frozen, especially as rain water soaks the soil and freezes.

However, as I told you before, there is one patch of our garden that is not frozen! This is a sandy bed where I planted carrots and which was heavily mulched with leaves and compost at the top. That fragile layer is slighty frozen, but if you remove the frozen leaves, the sandy soil below is totally not frozen, unlike the rest of the garden. This is because the soil is rather dry, and since it also contains clay, then the remaining little water does not freeze well.

This might be very good for starting crops earlier than planned. As the soil takes a long time to thaw, long after the freezing winter is gone. Usually the freezing stops in April but you can only dig the soil in late May.

So, as root vegetables like sandy soils and cool climates, this might be a perfect crop to start as early as early April, as the temperature starts to get more and more above freezing. If these root vegetables are perennials (like skirret, parsnips, jerusalem artichokes), then they have time to be established and restart growth very fast once the winter finishes. This "sandy soil strategy, covered by mulch" also facilitates the survival of some fragile herbs like mints or some flowers.

In short, all you need is to dig beds with some clay, some loose compost, lots of sand, and a mulch of fine leaves and grass. Your plants will enjoy having unfrozen soil as soon as temperature gets avove zero!

Talk about how is possible to do real Permaculture in Iceland!