Hot bed compost

Hi.  Every year I use a hot bed to keep my seedlings warm.  I have a cubic meter wooden box that I fill with fresh horse muck and straw. It's great fun and I love watching the temperature changes as well as keeping alook out at my seedlings for the new season. The muck mix is topped with a plastic sheet to keep the moisture in and i sit my seeds trays on top, on slats if i feel it too warm. This year I have got horse poo in woodchip bedding material , filled it up , watered it and wallop it went up to 60C in a day. It's -7 at night here at the mo. However! .... It smells very strongly and I'm concerned this ? Ammonia will be detrimental to any plant growth? Is the mix too high in nitrogen,  but it needs to be high to get hot? Shall I mix in some more wood shavings? I'm going to add a layer on top of the pile to see if it filters it out any way. Remixing the whole contents is do able if necessary but meanwhile any thoughts on reducing the ammonia release would be great thanks.
I searched the topics but couldn't find any references at all to hot boxes. Do you call these something else?
Thanks

Funnily enough I was just starting a hot box myself by nicking horse poo from our neighbours field. I think what you are doung should bd fine, it seems to be what they did on the Victorian Kitchen Garden if you remember that far back. Used to live in Braunstone, then Desford and taught at Aldetman Newtons then Western Park.

I tried it with bought cow manure and of course it did not work. I have to organise fresh manure! More and more difficult. Can you take a photo of your setup?

It definitely has to be fresh manure. Don't think it matters whose! Have a look at the compost systems folks use for compost toilet processing.
or this pallet arrangement
https://www.permaculture.co.uk/videos/benefits-hotbed

It works brilliantly for heat, it was the gases I was concerned about

Hello to Amanda from 'sunny' Leicester

My understanding is that if it smells, add more carbon and turn it, or oxygenate it by other means.

I really don't think you're doing anything terrible that's producing the ammonia smell. That is probably caused by an area that isn't getting a lot of air, which the bacteria that decompose that shit need to do it effectively. They are being choked out, and the bacteria that like low- to no-oxygen levels are thriving, and creating ammonia and/or methane as a by-product.

I could be wrong, because my composting usually takes different forms than a hot box, but smells don't often lie.

I really like the overall idea, by the way. If I ever had an overabundance of fresh horse manure, I would totally build hot boxes and heat a greenhouse or start seeds with it.

Good luck, and let us know how it goes!

-CK

I've done a fair bit of composting, though not a hot bed, but I think it sounds great. If I were you I'd give a try to adding a thick layer of wood shavings or chips over the manure, and see if that can absorb some of the ammonia. Maybe soak the wood a bit and then drain it before adding it, so that it's more ready to interact with ammonia? After two or three days if it doesn't make a difference in the smell, then try digging it into the manure.

One thing to be careful of when brining in manure from other people's farms, is if they are feeding commercially produced hay to their cows and horse, and if the hay producers used aminopyralid herbicides to kill off the broadleaf plants and keep the grasses only, these herbicides will survive the digestive system of the animal and the composting process, and if you mix that compost in your soil it will kill all your plants that are not grasses. Google it. It's a common problem now with people bringing in manure from farms. You can test it out by planting a few beans and seeing if they grow normally, because they are some of the most vulnerable and show the effects quickly. And ask the people you got the manure from where they got the hay for their animals.

cesca beamish wrote:Hi.  Every year I use a hot bed to keep my seedlings warm.  I have a cubic meter wooden box that I fill with fresh horse muck and straw. It's great fun and I love watching the temperature changes as well as keeping alook out at my seedlings for the new season. The muck mix is topped with a plastic sheet to keep the moisture in and i sit my seeds trays on top, on slats if i feel it too warm. This year I have got horse poo in woodchip bedding material , filled it up , watered it and wallop it went up to 60C in a day. It's -7 at night here at the mo. However! .... It smells very strongly and I'm concerned this ? Ammonia will be detrimental to any plant growth? Is the mix too high in nitrogen,  but it needs to be high to get hot? Shall I mix in some more wood shavings? I'm going to add a layer on top of the pile to see if it filters it out any way. Remixing the whole contents is do able if necessary but meanwhile any thoughts on reducing the ammonia release would be great thanks.
I searched the topics but couldn't find any references at all to hot boxes. Do you call these something else?
Thanks

Fresh manures are very rich in nitrogen, so they are going to put off ammonia as they decompose through the bacteria working.
To reduce this odor you need to add carbon materials and you also need to add oxygen (air) to the composting manures.
Good carbon additions are straw, wood chips, wood sawdust or dead leaves.
Ammonia in the air of a hot box or cold frame is not a great thing since it takes the place of the O2/ CO2 that plants use for respiration and growth.

Redhawk