Friday, November 07, 2008

A hotbed of activity

In the not-too-distant past, hotbeds were a fixture of nearly every household. Larger versions, in multiples, were used by market gardeners to keep city people in fresh produce all winter long. We're thinking about building one or two as an adjunct to the greenhouse, since they are easier to heat. I'm thinking to start heat-loving plants like tomatoes and peppers in them, and move them to the greenhouse once they are well-grown and the weather is warmer.
I'm sure most gardeners are familiar with coldframes - they create microclimates, that provide several degrees of air and soil temperature insulation, and shelter from wind. Hotbeds go one better by using a bottom-up heat source which encourages plants to grow in even the depths of winter. But where does this heat source come from?
Pony poop! That's right - horse poo composts at a higher heat than other manure, especially when "pre-treated" by making a 4 x 4 ft pile that is turned every 3 days for 9 days. All this moving around starts the fermentation process, and when you pack the bottom of the frame with this stuff, it will provide heat long enough to grow a crop of winter produce. Once the manure has finished "cooking" and the crop is harvested, the poop will have turned into lovely rich soil you can put on your garden.
There are some tricks to it, but nothing too complicated. If you don't have pony poop, electric heat cables can be used, or you can find a local riding stable (try craigslist) for all-you-can-haul horse apples.
The illustration below is of a "walk-through" hotbed. The manure bed is a lot deeper than in smaller hotbeds, but the convenience of a covered work area must have been worth the effort. The text this is from mentions building rows of them back-to-back, and I imagine the result would have been much like a greenhouse, only heated from below. We may end up experimenting with ways to move pony poo into the greenhouse to heat it, but only if we can also figure out how to easily move it back out again when it cools down.
So I'll leave you with a list of links to explore. Lots of different ways to build hotbeds, so hopefully you can sort out the best one for your circumstances. We're always looking for ways to add to our food supply, especially if we can cut expenses in the process. Hotbeds seems to be a great way to use a ready source of raw material (thanks Gemini!) and also to relearn an "off-grid" skill from the past.
The 100-year Hotbed from Mother Earth News - detailed article with lots of illustrations.
Coldframes and Hotbeds - from the University of Nebraska Extension
Hotbeds and Coldframes for Montana Gardeners - from the Montana State University Extension
Building hotbeds for your garden - by Gene Logsdon (A Seven Trees' favorite author)

No comments: