hotbin question

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sangela
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hotbin question

Postby sangela » Sat Jun 27, 2020 12:57 pm

I am a very amateur gardener, but am looking to buy a hotbin composter. I have loads of questions and have searched lots of sites and watched various you tube videos but everyone seems to say something different. I do not understand the nitrogen and carbon content but realise you have to use different stuff to achieve the right mixture.
I want to know if my understanding so far is adequate. You have to use grass, flowers, kitchen waste, leaves and green stuff for the nitrogen and paper, cardboard, wood chippings for the carbon and then bulking agent to allow circulation. What I cannot get a correct answer for is in what amounts I mix this to put in the bin?
What i also need to know is would a Hotbin M2 be too big for me (200 litres) if I live alone and only have a small garden? I have stacks of grass, leaves and green stuff in summer and can also get loads of shredded paper and would buy the bulking agent. In the winter i would just expect a much slower composting rate as I do not think i would have enough to keep it full. If you think 200 litres would be too big then I would have to settle for 100 litres bin which I think might be a bit small.
Would really welcome some answers from you experts :)
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Corby80
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Re: hotbin question

Postby Corby80 » Sat Jun 27, 2020 11:14 pm

Hi , first I suggest you join the Hotbin forum where you get answers to many questions you may have.
I have has a Hotbin for a number of years and find it very successful at producing good compost in a very short time. In terms of quantities, Hotbin recommend the following proportions of 5 handfuls of compostable material, 2 handfuls of shredded paper/cardboard and 1 handful of bulking agent, I use small bark chippings in bags from the garden centre. If you put I lot of grass cuttings you will need to increase the amount of shredded paper ( or preferably cardboard) to soak up the excess of liquid which grass produces. Although you can put in cooked food, I do not usually do this except in summer when the bin is operating at high temperatures, mine is currently running at 70c which is mainly due to the amount of grass cuttings in the bin at this time of year. In the winter it will drop to around 40c which is still enough to produce good compost. If you put in leaves make sure you shred them first (run over with a lawn mower) as they are very slow to break down. Also make sure that you chop up larges stalks like those from a cabbage so they break down quicker. This also applies to flower stalks.
Can't comment on the size but would always go bigger than smaller.
Good luck and good compsting.
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Stephen
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Re: hotbin question

Postby Stephen » Sun Jun 28, 2020 9:58 am

Hi sangela
Welcome to the forum.
You have already made the most important step, which is understanding the need to mix green & brown material.

My personal experience is this (background info: I live alone, cook from scratch, have an allotment and a small garden at home full of soft fruit)
When they were being sold cheaply, I bought one of those black plastic daleks. These are about 220+ litres. I found this never filled up at home. It is now on the allotment.
Later my mother donated the wormery she had to me. Small, about 100 litres. I got this going quite well for a while but didn't work out why it failed in the end. I was trying to get it restarted when a builder moved and the plastic (degraded by sunlight) cracked, so I threw it away.
Now I have a small, very small, compost bin of timber, open to the elements. This works as well as I need it to. With small volumes, you don't need the action to work more quickly.

On the allotment, I have daleks and a timber enclosure. There is an advantage in having a bin which is open, in that you can instantly see how well things are working because, if things are working, it doesn't seem to get any bigger.

If you have grass cuttings and garden material, I think you may well over whelm a 100 litre size. What I suggest is to measure (or estimate) the volume of grass cuttings you produce on the first cut of the year. Is this the biggest volume of material at any one moment? You will need to fit this into a half-full bin.
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sangela
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Re: hotbin question

Postby sangela » Sun Jun 28, 2020 10:39 am

Thanks for your reply, I have started collecting compost materials at moment instead of adding to my current bin in readiness for if i do go ahead and buy the large hotbin, so will be able to roughly measure how much of each material I collect over period of time.
I do collect quite large amounts of grass especially if it rains, I also get lots of leaves from trees next door plus leaves from my hedging and pruning of plants, so should have enough I think.
I will also be able to add more to the hotbin than I can currently add to my cold one as I currently restrict it to very fine cut up grass, leaves, flowers and shredded paper as it takes so long to break down.
Guess I have a lot more reading and understanding of the process before I can start doing it properly. It is going to be a bit of an expense to buy the hotbin and the bulking material if I then find I cannot get it to work properly, so a bit of a work in progress at the moment i think
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Geoff
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Re: hotbin question

Postby Geoff » Sun Jun 28, 2020 11:05 am

I'm afraid I've always found the idea of carbon:nitrogen ratio for composting a little ridiculous, I feel most organic matter is very similar what varies is the moisture content. I have found a website the recommends a C:N of 25:30 then presents this table that shows most things are close to this range so adding some shredded paper or cardboard to the mushiest stuff like grass cuttings sorts it out. Never come across the idea of a bulking agent but then I've only used compost heaps rather than a hotbin. I would only add fine wood chips or they take too long to break down. How good a compost you want to make depends on how you intend to use it. If you want to sieve it and use as part of a potting mix you need a perfect breakdown (difficult to achieve unless you put it through an industrial shredder then restack it like I'm convinced MD does). If you are going to bury it under vegetables a much cruder product is perfectly acceptable. Whatever you want you'll need at least two places. If you use a hotbin you'll need somewhere to stack the next batch while the first finishes breaking down or you could just use two traditional slatted bins, fill one and cover (check it is moist enough and water if need be) then start on the other.

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Stephen
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Re: hotbin question

Postby Stephen » Sun Jun 28, 2020 2:25 pm

I confess, I try to mix the contents of heaps up but they get what is available. If everything looks a bit soft and green, I add some cardboard. If I have lots of shrub cuttings, which are woody, I water it carefully and add leaves or turn it over to get some of the softer material mixed in.
Ken Thompson in his book Compost points out that in the end everything will rot down. Nature doesn't mix to specific ratios, we are just trying to speed up and manipulate the process a bit.
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Monika
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Re: hotbin question

Postby Monika » Sun Jun 28, 2020 7:37 pm

We contemplated buying a Hotbin some time ago but then read that to work efficiently it needs a constant supply of green material which (now we longer have an allotment and just grow vegetables in the garden) we cannot guarantee. So we have stuck with our three bin system: three ex-rubbish bins with holes drilled in the sides and bottom to admit air but no four-legged creatures. At any one time, one bin is 'live', one is 'stewing' and one is almost ready to use. I also regularly stir them.
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