Sunday, 24 February 2013

baby's first hotbed

This week I have learned something new about myself. As well as a flair for languages and the ability to solve cryptic crossword puzzles, (but no hard sums please) - turns out I can really stack s**t up. Discovering a new talent like this is a moment to cherish - when the hard times come around it will be there to call on. My mantra has always been, 'You'll never be in the gutter if you're till trained' - we're talking life skills here people!

I googled 'hotbed' to get a definition:
hotbed : noun
  1. A bed of earth heated by fermenting manure, for raising or forcing plants.
  2. An environment promoting the growth of something, esp. something unwelcome.

I'm on about the first one here - a low tech way of warming soil to get a headstart on seed sowing.  It's a technique that's been around forever, but was particularly popular in the eighteenth century before steam or electric heat became our default settings.  Garden writers like William Cobbett, John Evelyn and Gilbert White devote pages to elaborate descriptions of how to set about building your hotbed and Beeton's Garden Management features it as a job for January in the monthly calendar.

Having trawled through all of them, I set to and gathered up the following materials:

  • a great big* pile of steaming fresh** horse manure - I reckon I had about 2 cubic metres.
    • * you need a reasonable volume for this to work.  
    • ** it has to be fresh to generate heat.
  • some faggots of tree prunings - suggested by some writers as a way of building up the structure if you'e a bit short of manure. 
  • as many barrowloads of beech leaves as I could be bothered to rake up - some accounts suggest adding leaves as a way to temper the fierce heat of the manure. here is my step by step 'hotbed photo guide':



Build up the edges of each layer first then fill in the middle - 
make sure it's all firmed down so that it doesn't sink unevenly. 
Fill the frame with about 20cm depth of soil/compost mix.

I have a fancy glazed 'light' to go on top of the frame, but old window units would work just as well.

The heat should start to build up rapidly over the next few days - the books say that you should wait for the temperature to stabilise somewhere in the region of 21-23 Celsius before sowing seeds.  This seems wildly ambitious at the moment, but who am I to doubt the wisdom of the ancients?  I have stuck a thermometer in and will report on progress - I feel a chart coming on....


  1. you are a genius and this is a thing of beauty.

    1. why thank you miss Sian - I've been taking its temp like an over anxious parent.

  2. Your pile of you-know-what, actually looks kind-of 'beautiful'

    1. Not showy like a rose - but it does have its own special charm!

  3. Over the past few weeks i have been helping to build approx 10 large hotbeds, measuring about 6 x 12ft it has been back breaking work! the sides are built with scaffold boards and salvaged metal sheets. on top sits a frame structure with 3 removable 'lights' - basic window frames with polytunnel plastic attached. The result has been staggering, seeds seem to grow at an astonishing rate. We have also built a hot wayer system with some tanks surrounded by manure, this has provided lovely warm water

  4. Wow - that sounds impressive! Having access to a lot of manure that you don't have to transport very far must be really important when you're working on that scale.

  5. Gosh that is an amazing piece of work. Who would have guessed twigs, leaves and poo could be so helpful?

    1. If it was a bit bigger I think I would have got in there this morning! -2 in the garden, 16 degrees in the hotbed. Planning to sow some seeds in there this week.