Use can be made of the heat from the composting materials. Especially farm animals manure.

Autumn – dig out the soil from a sunken (insulation) cold frame and fill with 45cm of fresh horse manure, compacting as you go and moistening if needed; Put a layer of soil over as a root zone (light texture) 15cm deep when compacted; Heat from the manure will heat the soil as well as the atmosphere of the frame; Allows for the growing of winter crops such as lettuce, or over-wintering of tender plants; Summer use for crops such as courgettes or melons (base will be cool but a rich root zone); Autumn – dig out and use as well-rotted compost.

Below using compost/manure as a heat source - as a propagator:

Long lasting heat source but cools progressively. Hard work to refill each year.

Traditional Pineapple pit using old manure as heat source ( Heligan)

Needs fresh farmyard manure still giving off heat.