Permaculture Review the HOTBIN Compost Bin – They Love it So Much….
John Adams and Maddy Harland at the Permaculture Magazine review the HOTBIN compost bin. They loved it so much, they decided to add it to their green shopping supplement.
Over the years I have tried most ways of making compost but I have never found one that really suited my requirements until Maddy showed me her Hotbin. I was really impressed that it worked even in winter, how quickly it made compost (about 90 days) and that it could even cope with cooked food scraps. I just had to have one.
The Hotbin certainly gets hot. Last summer it was positively thrumming (up to 60ºC). There is never any smell from the bin and the process is fast. There were also no flies as their eggs cannot survive the heat in the bin.
We both love this product so much we have added it to our Green Shopping catalogue.
Download and read the full review here.
Buy your HOTBIN compost bin online today.
The Ultimate Guide To Compost Sieving and Sieves
Many people will use compost ‘as it comes’ from the compost bin and just dig it into the soil around plants or into the vegetable patch.
Sometimes it is preferable to have fine sieved compost for use in potting up seedlings or to use as a lawn top-dressing (it does wonders to reduce moss!). Large pieces of compost are hard to rake in and can cover the grass and act as ‘mulch’ – not the desired result.
Mature HOTBIN compost at 3 months
I have tested a few compost sieves and I thought it was time to summarise how they perform and offer a view on the how worthwhile sieving compost is.
Sieving compost can be tricky and labour intensive – it does not take too many lumps of wet moist compost to clog up the sieves.
HotBin Compost – Good and ready after 3 months
The Plastic Hand Sieve
A Plastic hand sieve will cost £4-10. These work OK if you just have a bucket of compost and the compost is not wet. When you only have small amounts of compost, the price/performance is hard to beat. However, once you start to get into bags or wheel barrow loads; the hand sieve is too time consuming. You tend to end up with aching arms and a stiff back! The plastic pan sieves struggle with moist compost – it will just roll into balls that won’t sieve. (There are a whole range of metal hand sieves that work the same as the plastic ones but cost a lot more).
A 33cm plastic garden sieve
The Rotary Sieve
The Rotary sieves cost between £30-40. They are OK with dry compost and compost that is already quite ‘fine’. However they tend to clog when used with moist compost. Some large pieces can jam in the rotary arm and you’ll need to stop and clear them out before carrying on. (NB this review was based on third-party input not our own test).
The CRS400 Rotary Soil Sieve
The Watford Sifter
The Watford Sifter costs approx £120-150. In my tests it worked better with soil than compost. It struggled with wet compost – it tended to clog and stick in centre of sieve and it did not tip ‘up and down’ far enough to move it from this position. Good for medium or large loads and certainly a good option if you have both soil and compost to sieve. With only small amounts compost, you might struggle to justify the cost.
The Watford sieving HOTBIN compost which is 3 months old and typically wet & sticky
Likes / dislikes:
- You get two screens – fine and coarse.
- Easy to push ‘up and down’
- A bit of a ‘pain’ to get the retained coarse material out of the sieve tray. In the end, I was continually lifting the whole box and tipping it out. It’s a heavy lift when not much is sieved. This issue goes away if most of the soil/compost gets sieved through – but if it is all fine in the first place there is no need to sieve!
The Scheppach Sieve
The Scheppach costs in the region of £350-400, this is a serious piece of kit. It is a trommel design (rotating cylinder) and uses and an electric motor to turn it so it also needs an electrical supply! It will handle significant volumes of soil and compost. We have not used this kit, but we know three large-scale gardeners/composters who do and they all rate it highly. If you are only using it 1-3 times a year, our opinion is it is questionable how much value you will actually get. Probably one for the professional and/or allotment/community schemes where you can share it. PS: It also takes a lot storage space.
The Scheppach RS400 rotart sifter
The Compost Sifter
Compost Sifter costs £155 (excl £40 delivery to UK). It comes from Belgium. It uses a similar rotary tunnel (trommel) design as the Scheppach – but it is turned manually via a handle. By long way, it required the least effort and sieved faster. The mesh (hole size) is smaller than the others (8mm). In our tests it struggled with wet compost, however, after initial disappoint with wet compost, it absolutely whizzed through dry compost.
(PS the photo below was taken before wheels had bee added)
The Compost Sifter – Assembled with just wheels to go
Likes / dislikes:
- Ease of turning – real winning feature
- Retains oversize and easy to get it out via panel that detaches
- It is very heavy – fine once set up on wheels, but you may need 2-people to get it out of box and set up on the frame.
- It still struggles with wet sticky compost – but so do all compost sieves!
(Oct 2013: the sifter team have introduced an ingenious compact version that fits on a wheel barrow:http://www.compostzeef.be/home.html )
For more information please visit the website above
The cheapest and most cost effective method
Please jump to this post to see the results of the most cost effective and low cost method
Sieving compost can be tricky and labour intensive, especially if it is wet and sticky as it tends ball into large lumps and clog sieves.
After numerous tests on HOTBIN compost, we think we are on solid ground to say if you want to sieve the naturally sticky wet HOTBIN compost you will have to dry it first (see how below). All the sieves will perform significantly better with dried compost.
Our next question is: Is it worth sieving compost?
This is not just about the cost of the sieve and the time and effort that goes into sieving. The most beneficial part of compost is the group of humeric substances. These compounds impact soil fertility as they enhance root uptake of minerals and water. It therefore follows the biggest benefit comes from digging humeric substances into the root zone. If digging in, one has to question if the effort to sieve out any big bits. Large over sized lumps will compost down in soil over 12-24 months. As long as the total volume of large pieces is low, the ongoing composting of these pieces is unlikely to affect nitrogen availability during the final composting period. With HOTBIN compost there is always about 10-15% of small 0.5-1.5cm wood chip (bulking agent) pieces that remain in the compost. Our tests show these pieces are covered in layers of humeric compounds. We believe these pieces of wood chip are slowly composted as they are coated and protected from rapid decay. Whilst in the soil, small pieces of wood chip also aid aeration and soil tiling.
There are applications where sieved compost is useful e.g. when used as a lawn top-dressing (i.e. raking in a thin layer of compost on to the grass), or when creating a potting mix for seedlings. Lawn care is a huge part of British gardening. I personally have seen good results from top-dressing moss ridden lawns (high clay, poor drainage) with sieved compost. For those of you that want to drop dress, the method is outlined below.
In summary, for most compost users and most types of compost application, we do not believe drying compost and then sieving is worthwhile.
Compost and lawn top dressing
- In late Autumn take out your HOTBIN compost and dry it (we spread it out as a thin layer on patio / large sheet polyethylene)
- Add dried compost to compost sifter or like to sieve
- Sieve and bag up
- Spread on grass and rake out to about 1cm layer.
This will take huge quantities of compost – but the rewards is you will not be spending much on lawn fertiliser or moss killer!
HOTBIN investigates an interesting composting method
We had an interesting question come in last week!
Was Black Soldier Fly (BSF) composting the most efficient composting system ever?
After many years in composting, we had not come across BSF before, intrigue and a hint of competiveness that any system might be better than the HOTBIN, we did a bit of googling. You learn something new every day!
- BSF (Hermetia_illucens) is a species of fly with native to America (with a cousin down in Australia). There will be a UK entomologist who will no doubt identify a cousin in UK, but so far not aware – and hence possible reason we have not come across them in UK)
- It has a niche habitat – rotting food/manure. The fly lays eggs in compost and the larvae (some would say maggots) eat the food waste – and they appear pretty good at it. (This is no different to house flies and or vinegar/fruit flies – BSL are much bigger and eat more!)
- The larvae are not meant to be allowed to hatch into flies (ie pupate), they are collected and used as chicken feed and/or fishing bait
- There are a number of specialist bins designed to house, retain and harvest the larvae. As a food waste disposal system, it more closely resembles worm composting.
What about claims to be the “most efficient”? We are always suspicious of ‘fastest and best’ and try and uncover the scientific facts. There was no reference to a specific quote and we did not see the claim on sites listed below. It looks like there is enthusiasm for BSF, as highly efficient and this enthusiasm comes from the visible disappearance of food waste as BSF larvae eat food within 2-4 days. If you compare 4 days to “composting” even hot composting at 30 days – you might think it’s more efficient. But decomposition (eating waste food) is just a set of biochemical reactions involving enzymes – the rules are fixed: the rate at which reactions take place is governed by the Arrenhenius equation – which basically boils down to temperature. BSF Larvae die at 40C, thermophilic bacteria operate at 60C and in many cases 70C.
In simple terms, larvae at 40C work at the same speed as bacteria at 40. If we say composting at 10C is rate X1, then larvae and bacteria at 40C are X8 times faster, but bacteria at 60C are 32 times faster – speed wise, we think no contest!
But is speed what we need to focus on? What are we trying to accomplish? Are we seeking to dispose of food waste fast, make fish bait or make great humus with high nutrient and water holding capacity that dramatically improves soil fertility? (With the added plus of diverting food from landfill).
Nature eventually recycles all plant and animal matter back to carbon dioxide and water. Does it matter if the larvae eat food, then the chickens eat the larvae and then the bacteria eat the chicken poo? Or that the bacteria eat the food (and release carbon dioxide), but leave some residual waste (compost) that gets eaten much later and then finally becomes carbon dioxide. Both routes are carbon neutral and better that sending it to landfill where it will decompose anerobically releasing methane. BSFL larvae eat the food and produce a small amount of residual compost like material. Composting and hot composting produces a lot of compost for the garden. Compost is beneficial to the soil before it is finally returned to carbon dioxide.
We should perhaps note that for many humans, the reaction (rightly or wrongly) to flies, larvae & maggots are negative. Even though BSF appear as good guy (does not bite, sting or carry diseases problematic to humans), we know from experience (backed up by surveys), that one of the biggest reasons people stop composting is flies and maggots. The prospect of actively promoting lots of maggots in waste food seems at best destined as a specialist area.
A text book start for the HOTBIN
The Compost Woman, who knows an awful lot about composting, reviews the HOTBIN! And I’m pleased to announce she has had a text book start as she has already reached 60C!
She started with an very full HOTBIN having plenty of material available for her base layer.
After 24 hours there was already a noticeable difference as the the material started to decompose.
She is a freelance Forest School Leader and Environmental Educator who works with both adults and children on all sorts of things. As well as a volunteer Master Composter and Master Gardener, helping people make compost and grow veg at home or at school.
So what is composting?
What is composting and how does it work?
The composting process relies mainly on bacteria ‘eating’ the good and garden waste. Aerobic bacteria require;
- Food and minerals
Open this document to see how the different requirements affect the composting process.
Not dissimilar to what humans need to survive and grow!
Warmth is not that widely understood. The speed of composting is directly related to how warm the bacteria are.
At Zero C – they are frozen and little happens. They work faster all the way to 75C. We normally describe composting as either ‘HOT’ ( 40-60C) or ‘COLD’ (>20C).
In most outdoor UK compost heaps, over the year the average temperature achieved will be 10C – i.e. the same as the ambient UK average temperature. There are many things that have to be right for composting to occur, but when it comes to how long it takes, there is one overriding factor that affects the speed (rate) at which waste decays and this is temperature.
In very simple terms for every 10C increase in temperature, the speed doubles. So if the average UK temperature over the year is 10C and we call this speed 1; at 60C (HOT), composting is 32 times faster.
To compare this on average you will find a UK open/outdoor heap typically takes 12-24 months to compost. If the same material was composted at 60C, it would take 12-24 days.
That is the real difference between COLD composting and HOT composting!
Supporting International Compost Awareness Week
We kicked off International Compost Awareness Week with a visit and display at the RSPB Saltholme Wild Life Garden and £10 off your HOTBIN this week.
Compost Awareness Week “aims to encourage more people to realise the benefits of home composting and the great results that can be achieved by using peat-free composts containing recycled material”
In summary the HOTBIN supports this as …
It produces great quality peat free compost
It recycles ALL cooked food waste and not just kitchen peelings
Reduces the amount of waste a household sends to landfill
It is quick as hot composting works up 12 times faster
You can compost all year round
It can be situated anywhere in the garden
You can compost easily with less odour and fewer flies
We took along some of the Potty Innovations cultivation stations with us to brighten things up.
How to Choose a Compost Bin
You can compost for nothing ( zero pounds / dollars) by piling your garden and food waste up in a corner. How do you decide whether to pay 20, 60, 185 or even 900 pounds (yes really!) for a compost bin? You ‘justify’ the cash by convincing yourself of the ‘value’. We show you how to do this by checking the composting features meet your needs at a price you can afford.
Sounds like hard work – why not just go online, look for a 5 star ratings and best price – job done.
Well you can do this. Compost bins like the HOTBIN have extensive customer reviews. BUT most online reviews go like this: “arrived (did not arrive) on time, it was easy (or hard) to set up. I will let you know how it works in 12-24 months – but few go back to add. So make sure you look for the really important five star rating – the bits that says: ‘it works it gives me great compost, it does what it says on the bin – it hot composts fast’.
We can summarise the process of how do choose the ‘right compost bin’ or the ‘best compost bin’ for you into seven steps:
Step 1 – WHY
Consider & define your composting objectives
Step 2 – WHERE
Review your available space and location for the compost bin
Step 3 – WHAT & WHEN
Review the seasonality, volumes and types of garden and food waste you produce
Step 4 – EFFORT
Consider how much time and effort you are willing to invest on composting
Step 5 – HOW
Consider which compost method (eg hot, cold, digesters, vermicompost) and which bin features are essential and which are nice to have (eg low odour, no rats, no flies, in/out waste list, sanitization)?
Step 6 – CHECK
Build a compost bin feature checklist
Step 7 – MATCH
Asses which compost will deliver the best price/performance
Before we go any further, let’s consider your time and effort to read this blog and research composting. Some may genuinely have the time available and interest in composting to fully research the topic – you should read the detailed steps below and take a look at these excel sheets we made to create your own evaluation.
The simple one:
The complicated one:
(We will load this on the website for you to download but if you are desperate for a copy get in touch)
Please share how you got on and what you decide!
The majority of readers looking to buy a new compost bin probably just want a ‘fast track’ to help them make a quick decision with a degree of confidence that they are choosing a compost bin that works. It’s not easy to fast track – there is no BSI standard, nor many user reviews of actual compost bin performance. If you are short on time, I suggest you skip the detail below and jump to the ‘reading between the lines section’ which has a few checks to help you gauge if the compost bin supplier has in depth expertise.
Step 1 – Consider your composting objectives:
- Do you want to make lots of rich/great compost for your garden that will improve its fertility and lessen/reduce your use of fertiliser and maybe even peat?
- Do you just want to keep the garden tidy?
- Do you want to make a more positive contribution to the environment by recycling all your food waste so your local council no longer has to collect and transport it to landfill or a central AD/IVC reprocessing plant?
- Are you just fed up with allocating more and more of your flower or vegetable patch to overflowing compost bins that never seem to do anything?
- What are your objectives on sustainability, organic gardening, good use of limited resources.
Step 2 – Review your available space and location for the compost bin:
- Some compost bins are limited in location (eg keep it in a sunny spot, or the opposite ‘keep it in the shade’, ‘only use on soil’, ‘do not use on clay soil’. You may have very little choice (eg it needs to go on the concrete by the garage). Your location may limit your compost bin choice.
- You might have a small garden and no space for a large compost bin, conversely you might have very large garden and taking 3 metre square for a traditional 3-bay New Zealand compost bin system might pose no issues.
- Do you want to the compost bin close to the kitchen so you can pop out easily in the rain to empty your food caddy?
Step 3 – Review the volume of garden and food waste you produce:
- Are you just going to compost seasonal garden waste (summer/autumn)?
- Do you want to compost grass cuttings (spring, summer, autumn)
- Do you want to compost food waste – produced all year round – ie compost through winter
- How much of each type of waste do you have? In my experience, very few garden composters or food waste recyclers accurately know how many litres (or Kgs) of waste they produce. Very few have any real desire to record and measure it either. Choosing the right compost bin size is also further complicated as compost bins can (given the right conditions to achieve ‘hot composting’) compost 32 times faster than a competitor bin that only facilitates ‘cold composting. So 20 litres of waste a week in one bin would rapidly break down within a week, but in another bin build up over time and need a 600 litre bin.
Step 4 – Consider if you want to ‘hot’ or ‘cold’ compost?
If you are unsure and want to learn more about ‘hot Vs cold’ follow the this link to Hot v Cold composting. The headline benefits of ‘hot’ composting over ‘cold’ composting are:
- Hot composting will destroy weed seeds – saving you time and effort in future
- Hot composting will destroy dangerous bacteria so you can compost all food waste
- Hot composting requires far less space to compost the same amount of waste
- Hot composting requires dramatically less time (eg 30 days Vs 360 days)
- Hot composting works all year round (cold heaps all but stop in winter, temperatures of 0-5C)
Step 5 – Consider how much time and effort you are willing to spend on composting:
This is hard – everyone tends to answer – ‘none / minimal’. The more a vendor knows this is critical to your choice, the more pressure to use the term ‘easy’ and the bigger the potential expectation gap and likely hood of user disappointment. There is always some effort (eg collecting food, turning, mixing, shredding). In our experience, things can be made very easy by habitually following simple method-steps. But investing the time to form habits can be challenging – especially at the start when people perceive the habits are taking more time not saving time.
So, now you have a clear picture of what you want. Next, how do you check and match the compost bin against your composting objectives?
Step 6 – Build a compost bin feature list:
Build a feature list, locate the top 10 commercial bins, score each feature, eliminate those compost bins that do not fit your needs to produce a short list; then weight/score the remaining compost bins to find the best match.
Step 7 – Asses which compost bin will deliver the best price/performance:
Rate (Score) the competence of each compost bin against each feature, ie establish the performance and derive and overall value for money score – the million dollar question!
Commercial Product managers do this kind of work as their day job – but it is likely very few composters, gardeners or food waste recyclers have the time or inclination to do this.
If you have both; follow this link to the ‘compost bin competitive evaluation sheet’. You will find 12 widely available compost bins types and brands professionally analysed. You can play around with the scores and weighting to see which you think is best.
Accepting the majority of readers will not want to do this; how do you ‘read between the lines’ and spot the vendor marketing hype (that’s the polite term!).
Reading between the lines:
- The obvious choice is to seek user recommendations. As part of our competitive research we scan websites for ratings and reviews of compost bins. Often they just state: the bin ‘arrived/did not arrive’ on time, it was ‘easy/hard’ to assemble, followed by ‘I’ll let you know how it composts’. There are only a few reviews where people state: it delivered great compost just like the vendor said in X days.
- Validate vendor promises… (eg compost in 7-days). Look for detailed scientific study from reputable independent organisation to support.
- Check vendor expertise – does their website offer real in-depth hands-on composting advice or does it just regurgitate the same old ‘in/out’ list that applies to ‘cold’ composting without offering explanation for how it differs for hot composting?
- Look for vendors with expertise in composting science & engineering. All composting (from the autumn leaf on the floor to an industrial scale IVC plant) obey the same laws of nature like cooling rates, rates/speed of biochemical reactions. Should you the consumer need to know about the science and engineering of composting? Of course not, but we believe your compost bin vendor does.
I said in the introduction, you can compost for nothing (£0s) by just piling stuff up in an open heap. To justify the cash outlay you have to generate ‘value’ and you do this by checking the compost bin features deliver against your composting objectives at a price you can afford. We hope the above tips combined with the tools in the links will help you create ‘value’ and help you decide which compost is right for you.
In my opinion, as soon as you set an objective like ‘compost all food waste with low odour and no rats or flies’ or ‘compost using an easy recipe’; ‘compost fast’; ‘compost year round’ then you need a specialist bin that offers great performance at an affordable price.