An ingenious method of providing warmth for tender plants, without the necessity for any elaborate electric heating cables, is to build a 'hotbed', that uses fresh horse dung to heat plant roots' When the manure rots down it gives off heat that is then trapped with the overhead frame. In the nineteenth century, not many big gardens would have been without a hotbed, which enabled the gardener to grow exotic fruit and vegetables which would otherwise not have survived one winter, let alone provided a crop. To build your own hotbed: Dig out a shallow hole in the ground then stack a large amount of fresh manure into it and leave it for roughly five days to permit heat to build up. You may need to turn the pile and sprinkle it with water if the weather is hot - if it dries out, the decomposition will slow down. The pile should not be too small or it will never have the capacity to build up adequate heat - four wheel-barrow loads should be sufficient to make a good-sized pile. After about five days, when it should be really hot, flatten it as much as possible and cover it with a layer of soil to a minimum depth of 7.5cm.This will ensure an even and regular rate of decomposition, and corresponding heat output
Place a frame over the soil topped compost to preserve the heat. The frame must have a lid that may be opened if ever the temperature rises too high. Plants can be grown soil loam, while seeds need to be sown in trays and put on top.
Raised beds can act as a hot bed as they warm up during spring. Raised beds may be any height or length but need to be sufficiently narrow so that the crops may be easily reached and tended to without the necessity to walk over the soil. This means there is no danger of compaction and the soil structure isn't damaged. Equally as there isn't a need to leave room for access between rows, your crops can be planted closer than normal, increasing yield whilst reducing weed growth. Beds 1.3m in width are perfect. To be successful the beds must be constructed correctly. Edging must be tough enough to hold back the weight of the soil in the beds, and the height needs to allow for a rise in the level of the soil as you add mulch and compost each year. Among the simplest of edging constructions are lengths of timber held in place by wooden pegs hammered into the earth, or else you can construct longer lasting beds with bricks and mortar. To raise the ground level, firstly skim the topsoil from the adjacent paths and place it in the beds, after that work sizeable amounts of organic matter into the soil - about 6kg per square metre will really loosen up the structure. lf the beds are prepared properly they ought to need little more than light hoeing and a sprinkling of fertilizer for several years.