Yes you read that correctly! I heard a TV personality talking the other day about his "straw bale urinal" and it got me thinking. Take a straw bale, keep it in a greenhouse over Winter, and ask your friends (if you have any left) to make contributions for an eco friendly cause. There is a sound science behind this madness. Nitrogen + Carbon = HEAT.
This really does work. A straw bale "treated" in this way really can heat your greenhouse to a certain extent. If you don't fancy using re-cycled tea, coffee or beer.. for this purpose then you can surely wimp out with some liquid high nitrogen liquid fertilizer. Treat the straw bale and over the next few months it will throw out an astonishing amount of heat.
In the Spring, you can hollow out two small holes in the top of the straw bale, fill them with potting compost and plant your greenhouse cucumbers in them!.... Now I am sure that I have a spare toilet seat up in the attic...I'm sure I do.