Hot beds are an ancient growing technique which uses the heat provided by decomposing manure to keep an enclosed growing space warm. They can be used instead of a greenhouse or polytunnel, or used inside them to push the boundaries of what you can grow even further.
Hot Beds by Jack First (Green Books 2013) is the first book in many years dedicated to the construction and use of this ingenious growing system. Hot beds were famously used by gardeners in large Victorian estates to grow vegetables for the Master’s table out of season. But they had practical, mass market uses too. Up until the First World War, acres of hot beds in Paris were used to send thousands of crates of fresh produce to Covent Garden each week. Lettuces, radishes, carrots, asparagus, celeriac and turnips were exported… between Christmas and March!
In Hot Beds, veteran grower Jack First recounts his re-invention of the hot bed as a practical twenty-first century growing technique. Used outside or under cover, the hot bedding system allows vegetable growing many weeks before it would be possible outside. The author has used the system to produce crops as early as March in his native Yorkshire – quite an accomplishment.
I’d describe this book as ground-breaking, except that there’s no actual digging involved.
A hot bed is made up of an outer frame to hold the manure (similar to a regular raised bed), which is then topped by a slightly smaller ‘growing frame’ partly filled with a growing medium – typically a mix of topsoil and good compost. This is angled slightly to catch as much light as possible, and topped with transparent covers or ‘lights’.
Hot Beds is well thought out and clearly presented, with chapters on constructing both the frames and the hot beds themselves. There is a vital section on how to plan out your year’s sowing and cropping, but it is here that Jack First’s considerable growing experience could be a little daunting for novice gardeners. Growing in hot beds is defined by its differences to outdoor growing, so a fair degree of experience on the part of the reader is assumed. Thankfully, there’s also a ‘hot beds calendar’ featuring a range of sowing dates which should be really valuable for less confident growers, as will the comprehensive section on individual crops.
Manure – and plenty of it – is the mainstay of hot bed growing, so it’s a system that can hardly become mainstream. But as anyone who has grown using hot beds will tell you, the results speak for themselves. With fertility building year on year and the ‘gentle heat’ of a properly managed bed, conditions are far better for plants than even the most mollycoddled electrically heated propagator. What better reason to get friendly with your local stables?