Hot compost box

[bluebell]

Hi I have been looking at the very expensive hot compost boxes and wondered why they say you need a bulking agent? Hand any of you tried one and was it any good?

[charles]

I had the same thought Bluebelll. Steph is having a go next month..

[Hawfinch]

Hi,

first post on the forum.

I’ve been reading a blog called http://www.the-compostbin.com/ – she has a lot of information about using the hot compost bin, trials and comparisons with normal Dalek-type composters. Hope it might give you some answers.

[Don Foley]

This systems looks good but the bin seems rather small?
I would personally stick with the traditional method.
I use two 1 cubic meter bins constructed from recycled Pallets.
I start filling one in August/September. By February/March it is full and “cooking away”
nicely. I transfer the contents of this bin to the second bin then to finish off. In September this is ready to use so I sieve it and bag it until November when I spread it on my vacant beds.
The contents of the 1st bin are transfer to the second bin after I have removed its contents and thus the cycle begins again.
There are two things I do in addition. I turn/aerate both bins on a regular basis – once a month. In addition from time to time I will add a little FYM to each or Compostmaker.
This works well for me and I get really well rotted Garden Compost when I need it and for little effort and no expense

Don.

[bluebell]

Thanks for the comments and links, which are most helpful. Don Im sure that you have great compost but I just don’t have the time to turn my compost every month. once or twice if it is lucky. I believe that you don’t actually need such a big bin as it composts so much quicker. Anyway we will se if I can pick one up at a reasonable price and give it a go.

[Don Foley]

Hi Bluebell,
In actual fact with composting size does matter!
The bigger the bin the more you put in, the hotter it gets.
Obviously you also need to be reasonably careful about keeping the carbon/nitrogen ratio right. I would stress reasonably careful. Home composting is not an exact science and you will find from time to time that you need to tweak the contents to get/keep the process going.
For instance if the contents get too dry or too wet or very smelly.
When I say turn I don’t literally mean turfing out the contents and then refilling. I simply dig over to a Forks depth and this only takes a few minutes. Turning in this way on a regular basis produces usable compost in 5/6 months and if you get the timing right you will always have compost when you need it.
Don’t get me wrong, I’m not decrying the Hot Compost Box system but I can’t really see the need for creating compost in 18 days. After all you will, using no-dig, for the most part, only need to apply your garden compost once a year. Of course you will use it at other times for other reasons, earthing up, etc., but for the most part you will only be using it for top dressing your beds in Autumn/Winter.

Don.

[bluebell]

Thanks Don, Firstly I do like to experiment as that is how I learn so it is curiosity as much as anything. Secondly Im running out of space on the Plot and so anything that can give me more room for planting is good, thirdly I am hoping to pick one up at a very good price 😉

[pete]

There is a question on this weeks gardeners question time about hot composters.

[Leif]

I am sure they explain on the maker’s web site, however I think it is to do with adding carbon, so you get a balanced mix. I think they say you can use shredded wood. I considered one, but they are very expensive, and I worry about their longevity given the material they are made from. As said, size does matter, a big pile can get very hot. I created a huge pile when clearing my garden, and the inside turned grey and steamed, it looked like burning ash and was too hot to touch. I bought ~1000L wooden compost bins, which seem to do the trick. The advantage of the hot bins is that because they are insulated the outside of the compost will also get hot.

The only reason I might consider one is that the temperature will kill weed seeds, so I could use pony poop from the local roads. The last time I used pony poop, I ended up with huge amounts of nettle seedlings in my veg beds.

[bluebell]

Thanks guys. From research it would appear that the bulking agent is only really required if you are composting meat etc. (presumably helps keep the rats comfy).
Thanks Pete managed to catch GQT – they were not big fans! We will see if I can get it cheep enough it will be worth a go.

[zuf]

Bulking agent is needed for good ratio of C:N, otherwise you don’t get good composting going on – the stuff just rot in there no matter the temperature.

[bluebell]

Well the experiment is not going to happen in the near future as the one I had my eye on has gone up to silly money. Thanks for all your input and I would still be interested tp hear how Stephs experiment goes.

[zuf]

Until then, a much cheaper way of hot composting for those who never heard about it.

One hot composting method, the Berkeley method, developed by the University of California, Berkley, is a fast, efficient, high-temperature, composting technique which will produce high quality compost in 18 days.

The requirements for hot composting using the Berkley method are as follows:

Compost temperature is maintained between 55-65 degrees Celsius
The C:N (carbon:nitrogen) balance in the composting materials is approximately 25-30:1
The compost heap needs to be roughly 1.5m high
If composting material is high in carbon, such as tree branches, they need to be broken up, such as with a mulcher
Compost is turned from outside to inside and vice versa to mix it thoroughly.

With the 18 day Berkley method, the procedure is quite straightforward:

Build compost heap
4days – no turning
Then turn every 2nd day for 14 days

source (more details on a subject): http://deepgreenpermaculture.com/diy-instructions/hot-compost-composting-in-18-days/

[bluebell]

Thanks Zuff. I had seen that but 2 things put me off.
1. It was carried out in a significantly warmer climate and with large amounts of materials
2. the amount of time and effort required to turn it without mechanical means this would be quite arduous.

[zuf]

True, but from spring on you can do it in England, no problems.
Also, you get 1 cubic meter of compost in 18 days, it’s worth it to do it once or twice in a year if you have time and material.

[Author]

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