A hotbed is a rapidly created compost heap.
But how do you achieve it in the middle of winter, when there is very little green matter to provide the heat?
I show you a common material: fresh horse manure with the straw bedding. I use that because fortunately, my neighbour has a lot of it!
Horses do not digest fibres so much as cows. This makes the compost heap more aerobic and higher in nitrogen.
Nitrogen in composting terms is a green, which is necessary for heat. Plus the straw provides structure, and warmth over a longer period. Another bedding could be woodchip, but it is slower to heat.
This is a summary pf methods I have devised over 10 years of doing this in one corner of my greenhouse. The area of 1.2 m², or 4 ft.², is I reckon the minimum you need to provide a worthwhile amount of heat over a long period of propagation.
I need the heat for different seedlings, from late February until the middle of May. We top up the hotbed every three weeks or so during that period.
Filmed and edited by Edward Dowding https://edowdingfilms.onfabrik.com
At Homeacres, Somerset UK on 20th February and then on 8th March.
My helper is Adam Wood, who works permanently at Homeacres and is an expert on mycology, see his channel @myco_ad
00:00 Introduction, why I started making hotbeds under cover
01:09 Adding fresh manure with straw to the hotbed
02:12 Putting on bits of wood stage by stage, and a metal bar to keep it tight in front
03:00 Making a hotbed using different materials, and the benefits of using straw
04:13 A potential problem, ammonia within the steam
05:35 The importance of packing in as much manure as possible
06:41 Consideration of the work involved in making a hotbed like this – is it worth it?
07:22 Hotbed dimensions
09:17 My experience of making an outdoor hotbed
09:36 Concerns about pyralid in horse manure
10:18 Levelling the hotbed
11:18 Keeping the greenhouse windows open to allow gases to escape
11:49 A look at the hotbed two weeks later
12:27 Damage to seedlings from not having put the plastic back on to protect against the gases – not something to worry about too much!
13:13 A look at the temperature
See these two videos showing the outdoor hotbed I made in 2018:
https://youtu.be/ExdnLqo3rYs
https://youtu.be/tyhs7_HjAcM
More on propagation using a hotbed: https://youtu.be/nJ5csH9K3aw
You can join this channel by paying a monthly fee, to support our work with helping gardeners grow better. We recently sent out over £2000 to different projects around the UK, to help them buy a worthwhile amount of compost. As a member you receive monthly videos made exclusively for you:
https://www.youtube.com/channel/UCB1J6siDdmhwah7q0O2WJBg/join
I have a large horse farm around the corner where I can get all the bedding I need but don't have a greenhouse at the moment. How bad is the smell in your greenhouse after building that hot heap?
If you want to really get it cooking spread over ground then run over with lawn mower then wet as you build 3" layers
Can I suggest using a ratchet strap to go around the boards, especially the trailer, being an hgv truck driver it did make me cringe seeing that thin wire ????????????☀️
I volunteer at a disability adult activities centre as gardener and would love to build a hotbed in their polytunnel but unfortunately the local foxes have torn great holes in the polythene and the recent stormy weather has buckled the frame, it's over 30years old, so we wouldn't be able to keep the foxes off an young plants on the hotbed ????????☀️
Short answer…………………….. Yes.
I built mine this year using pallet collars, extremely stable and very easy to build up the layers.
Looks great Charles, homemade heat mat and heat for the greenhouse ????
Can we build a hotbed outside or does it need to be inside a cover/greenhouse only?
This really works. I am blessed to have fresh horse manure delivered to my allotment, so no shortage
at £30 an hour you are making a net loss of £20 an hour and thats if you dont pay for anything….you must have another income sourse….I still like your vids but dont have your money……..
Brilliant.. I was wondering if you put the hot bed in the middle of the green house… (say 2m x .60cm/1m down the middle) would this provide more heat to the overall greenhouse and retain it better. Also heating the ground more rather than being at the door?
Then, covering it over in winter with staging /benches for pots and fill up next winter on top of or would it all need replacing and in which case be matured manure to then go on the garden?
Thanks!
Have a look at Jack First’s book on the background to hot beds.
Thanks to Charles for a very educational video as always.
That’s going to be lovely compost in a few months. Fingers crossed it doesn’t have any of these dreadful poisons in it.
Would a solid layer of dry wood chips (tree mulch) on top help absorb some of the ammonia and prevent that damage?
Have you tried using a natural Saponin to help water the pile, something like yucca extract?
Well said about amino p. In horse manure. Perhaps using a humic acid across fields where animals are regularly urinating might help address the conditions that preference thistle
Do you think that it would work with the stored in bags manure that were preserved since last year autumn? ????
I fell and knocked myself out this week. Watching you wobbling on the crates and going where no man should was giving me the heejeebeejees. Would the heap work if you "filled a pit" instead? I don't know whats attractive to bees in my compost dalek but a bumble bee was trying to get in there between rain showers. (Warmth? Shelter? Food?)
I wonder how many generations of our ancestors used a method like this. They didn’t have heat mats and they needed food.
Can you hot bed horse manure ?
That is quite a bit of heat. What was the general temperature outside day/night?
What is the temperature inside greenhouse day/night? Thanks.