KEEPING THE HOTBIN HOT
How do I keep my HOTBIN composter working hot? My HOTBIN seems to have stalled – It won’t go above 40C any more…
Here at HOTBIN composting we are passionate about our brand promise that given the right volume and mix of waste everyone can hot compost at 40-60C.
We do not have many customers who struggle, and normally a combination of our Q&A database, email support or our unique composting photographic analysis service get their HOTBIN composting on track.
You can imagine therefore we get a bit hot under the collar when we find a customer where everything seems perfect, they have been hot composting for a while, all the settings are right (valve, door on, etc) the mix is right and there is nothing obviously wrong and yet the HOTBIN suddenly sticks persistently at 30-40C and will not rise. We have termed this “a stalled HOTBIN”.
Who is affected by stalling?
Firstly this is not to be confused with customers who have never reached 60C (if this is the case, please check out the FAQ: How to get to 60C check list. Stalled HOTBINs are where it has been working perfectly for months at 40-60 then suddenly it will not rise above 40C.
This is not a common occurrence and there are only a handful of reported cases. A dedicated customer (Andy U) wrote in and suggested an adaptation to help and this kicked off a summer of activity and research.
Why does it happen?
We have identified one central issue: restricted airflow through the base layer. (Think of the HOTBIN as a fire in the chimney, you add new waste onto the fire to fuel it. As the heat rises is ‘draws’ fresh cold air in at the base. This air is drawn up through the base layer. If not enough air flows, the bacteria are restricted and hence the heat produced is restricted.
What causes restricted airflow?
The HOTBIN works under many different waste conditions. However, we have identified the causes that can tip the balance and create restricted airflow:
- Base plate is ‘plugged’ (see below)
- Ultra compressed base layer
- Dense, compressed, wet layer of either paper or grass
Top tips for fixing A stalled HOTBIN
If you are suffering from a stalled HOTBIN, here are our tips for fixing it:
- Check to see if your base plate is ‘plugged’ (check this post to understand what we mean by plugged rather than normal operation where the holes are covered with compost).
- Sprinkle a couple of handfuls of wood chip on the base plate after each emptying to reduce the chance of plugging.
- Empty out the base layer at least every 6 months. Longer and it will lead to ultra compression of the base layer.
- Always add bulking agent – this is critical with Food waste, but it will also help prevent compression of any waste
- If stalled, stir the top half of bin to help aerate and break up any dense layers.
- Check for thick layers especially in lower half bin. – eg a solid layer of wet grass or compressed wet paper.
- Check mesh plate for leakage of water/leachate. If lots of leachate cross check to see if your real issues is that your waste is “too wet” for hot composting
Worms and compost
Worms and Compost
The HOTBIN team were recently asked if the partially composted material in the base of the HOTBIN could be moved out and placed in a wormery.
Worms will eat both old or new organic plant & food waste. We are not sure what benefit you get by taking waste from your HOTBIN into a wormery. If you are seeking a fine small grain vermicompost, then might be worth noting worms do not eat large woody type pieces – so the large bits will still be in the wormery at the end as well as in the compost. Both process end up with very similar products.
(We have already blogged on the topic of what makes good compost and what it look like – you may find this blog post useful).
You also need to look at the practicalities. It depends on what type of wormery you will use as they come in all shapes and sizes. If you are thinking of a typical tower/beehive type stack, my guess is it would be impractical to take out a wheelbarrow of rough mulching compost to add to a small wormery tray. As I understand the tray design – they work best on ‘little and often’. With lots of rough grade compost, in our view a maturing bin is a much better option.
If you are thinking about this because you are running out of capacity, there might be better ways of managing – such as using a maturing bin within (see our post managing multiple HOTBINS). The worms will inhabit this type of maturing heap so you get ease of use and worms. There are circumstances where worms will inhabit the HOTBIN – our post worms in the HOTBIN might be useful.
Sarah (the compostwoman) and some of the other Master Composters all run multiple systems (the job requires it!) so we will open up the blog/post and see if they can advise….
Rats and Composting
Rats and Composting – avoiding the pesky vermin
Right at the top the top of the list of reasons people do not compost or have stopped composting is rats. Either you have seen one near your compost bin or you never want to see one near it.
A key question then: is your compost bin rat proof?
We have done a lot of research on making the HOTBIN rat proof. We know if you talk to experts such as pest control officers or Master Composters who see hundreds of compost bins in many different homes they will tell you – any compost bin can be attacked. The idea of a rat proof compost bin is a myth and what you should look for is a well designed bin that can demonstrate (via customer feedback) that it is does not attract or get attacked by rats.
HOTBIN has a tremendous record: 99.5% of all customers report no rat issue when composting with the HOTBIN. AND remember, most HOTBIN customers add all food waste including cooked food, meat, fish (ie the bits that tend to cause more problems) into their HOTBINs
Achieving ‘rat proof’ status is not about building a concrete bunker. It involves understanding rat behaviour and designing out the things that attract them to the compost pile as well as making it physically hard for them to break into the bin.
We present below a little more of the science and background on how and why the HOTBIN should allow rat free composting.
Is the HOTBIN rat proof? NO – rats can eat through almost anything – including plastics, metal wire and concrete. It is more accurate to say the HOTBIN is one of the most rat resistant home composting systems available.
Can rats chew through the HOTBIN walls? YES, but it is unlikely – see reasons below.
Will I get rats in my HOTBIN? It is very unlikely. 99.5% of HOTBIN users report no issue.
Can I compost food waste (including meat and fish) in the HOTBIN without rat problems? YES , 99.5% of users report no issue.
Why are rats attracted to composting bins?
We need to start by asking what the rats are looking for? They want a warm dry place to nest, food to eat, and shelter from predators. Rats will burrow under soil and through chicken wire to get to a warm, quite nest site. They have teeth that grow for a lifetime. They actively need to gnaw hard surfaces to keep them in trim. Rats find food via smell – the odour that comes from all decaying material attracts rats.
Do all compost heaps have the potential to attract rats? Yes, but adding meat and fish to a cold compost heap will increase the chances of attracting them as proteins give off more pungent odour and rats prefer meat and protein over a plant matter.
What do rats eat? rats are omnivores and will eat anything – even vegetable peelings and green plant material. The more desperate and hungry the more they will eat things they may not like! Like humans, rats like meat, food that is tasty and easy to take-away.
It is no coincidence that compost heaps are often associated with rats – a compost heap has the potential to be a ‘warm home’ with a ‘takeaway’ attached.
Do all compost bins have rats? NO. Millions of UK homes compost without rat problems.
What do rats not like?
a) Contact with humans – often the big difference between a compost heap with and without rats is the number of times the heap is attended by humans.
b) Open spaces – they prefer dark quiet places away from predators.
c) Flat smooth surfaces – they cannot get their jaws around or teeth into flat smooth surfaces to gnaw.
d) Exceptionally cold conditions – a cold winter is good news as more rats die from the cold and starvation. It is bad news for some unlucky households, as hungry rats get more desperate for food and shelter so they attack more compost bins and homes.
The HOTBIN claims composting food waste without rats – What does this mean and how does it work?
We do not want any potential customer to misunderstand our advertising. When the HOTBIN is operated correctly it will not attract rats. We do not mean that the HOTBIN is rat proof and capable of resisting a full on attack by a rat.
The HOTBIN minimises the risk of attracting rats using good design;
- The HOTBIN minimises composting odours via aerobic composting and filters odour out through the valve in the lid – Therefore there is less odour to attract rats.
- The HOTBIN disperses the small amount of odour coming out from the lid using a filter and an aeration valve which is 1m above the ground and hence above normal rat runs.
- The HOTBIN keeps the compost/waste moist which is not a desirable dry nest location site for rats.
- The active uppers layers in the HOTBIN can be retained at 40-60C. 60C is too hot for rats to survive.
- The HOTBIN wall surfaces have rounded edges to prevent gnawing – There are smooth rounded corners with no sharp edges or gaps.
- The HOTBIN has no holes for them to enter into the HOTBIN.
- The EPP plastic used in the HOTBIN has no food value to rats. They will not eat the plastic as food.
- Attending the HOTBIN to add food waste every 3-4 days will deter rats.
The HOTBIN has been designed to be located close to the house to encourage recycling. If you locate your HOTBIN in an open aspect, near human activity it will greatly decrease the risk of rats being attracted to your HOTBIN.
We continue to improve the design of the HOTBIN to ensure it becomes even less attractive to vermin. However customers and prospective customers need to be aware which situations and actions will increase or decrease the chances of a rat being interested in their HOTBIN.
When you already have an infestation of rats in your old compost heap or garden, immediately replacing the old compost bin with a HOTBIN in the same location is high risk. You are taking away the easy food source (old compost heap) and just replacing it with food behind a closed door. The rats are going to get desperate and seek a way through the door and they will be highly aggressive in finding food once starving.
If you already have rats, it is much better to:
- Remove the old heap and all food waste. Cease all composting for 2-3 months. Encourage the rats to leave first.
- For serious infestations (especially in urban areas) get the professionals in to trap and remove them first.
- Add extra protection when setting up your HOTBIN. For example, wrap 1 cm square wire mesh (commonly called squirrel wire mesh) around your HOTBIN to protect it. When the infestation has been cleared, then a correctly operated HOTBIN will not attract rats.
When setting up your HOTBIN:
Locate your HOTBIN on a hard surface – Place it on flagstones to avoid rats burying underneath and using it for a nesting site. Do not rest the HOTBIN on 4-small flagstones at the corners as this will just make it even easier for the rats to create a nesting site.
Keep the door hatch panel closed – Hot odours rise however some odour can escape around the door hatch panel while the HOTBIN is being filled. At all times ensure that the HOTBIN door panel is tightly closed. When replacing the door panel (eg after emptying waste); you must wipe around the edges of door and hatch to ensure no loose pieces of waste are left in the joints. Even small pieces of waste will create weak spot and the door will not correctly seal. This weak spot could be attacked.
Take care when filling the HOTBIN – waste in the base puts pressure on the door and can ‘pop it open’. It is very important you use both cam belts (supplied) to ensure the door is on tightly. You should not be able to see any waste through any gaps around the door panel.
Always clean up – ensure no food waste is left around the base of the HOTBIN, this is a free takeaway and will attract rats.
Look after your HOTBIN – Repair any damage to the HOTBIN.
In summary, the HOTBIN has been designed to reduce its attraction to unwanted visitors and in 99.5% of cases this works. The location and keeping the area tidy around your HOTBIN is also important in minimising its appeal. Unfortunately we cannot guarantee 100% that there will be no occurrences but we are continually working with our customers on how we can limit this together through education and development.
Compostable Bags in the HOTBIN
The hazards of using compostable bags in the HOTBIN!
After two recent customer enquires we thought we should post a reminder on why you should not use compostable bags in the HOTBIN.
One of our HOTBIN cafe customers has been collecting food waste from the kitchen in compostable bags and loading these straight into the HOTBIN. The other a Yurt Holiday Camp Site has been adding bagged humanure from their dry toilets into HOTBIN.
Both have has issues with low temperature and high odour – not what we want in the HOTBIN!
CAN I ADD COMPOSTABLE BAGS (used to line food waste kitchen caddies) IN THE HOTBIN?
We do not recommend adding the compostable bags in to the HOTBIN.
We need to be clear: these bags are compostable and do biodegrade in the HOTBIN, in fact they will degrade very quickly, in our tests at 60 C they broke down within 30 days – which is per the manufactures specification and the various biodegradability tests).
Why we advise against using them in the HOTBIN is that they prevent effective aeration of the food inside the bag. The bag “seals” the contents from airflow. The food inside the bags decomposes anaerobically during the first 1-10 days before the bag itself degrades. You end up with a mushy smelly mess. Very quickly the bags of mush compress and form an impervious layer – the whole bin starts to cool and go anaerobic. As the temperatures falls the bag decomposition slows – you end up with HOTBIN that needs completely emptying and the bags separating out – a very stinky and unpleasant job.
You can of course tip the waste out of the bag, scrunch up or shred the bag and then add it to the HOTBIN. The bag will now decompose without affecting aeration of the whole bin. (In our opinion – this defeats the objective of using the bag! If you want to keep your caddy clean and tidy, try a paper bag or 4 sheets of paper to make a lining. You can empty the paper and food straight into the HOTBIN.
WHAT OTHER NAMES ARE USED FOR THE BAGS?
Compostable bags, Biobags, biodegradable bags, PLA, PLA-Starch, Corn-Starch and a whole range of trade names
MY COUNCIL COLLECTS THESE BAGS – HOW COME THEY DO NOT HAVE PROBLEMS?
Large scale industrial composting (eg Local Authority Composting Sites) do not experience similar issues with compostable bags as all waste (including compostable bags) is shredded before adding to the composting plant).
HOTBIN on Love your Garden
HOTBIN made a special appearance on the new series of Love Your Garden on Tuesday 30 July at 8pm on ITV1.
Love your Garden is an Alan Titchmarsh programme featuring fabulous garden make-overs for some very special people, it aims to inspire you to get out there and love your garden too!
During the show Alan shows how to turn the the most unlikely outdoor spaces into life enhancing havens, as well as giving handy horticultural hints and tips along the way
This season HOTBIN helped form part of a particular Love Your Garden in Hereford…Rhyanne and Mike were absolutely delighted with their new garden. We’re sure the HOTBIN will be used immediately and will form part of their routine to help keep their garden looking great by recycling food & garden waste into rich compost!
How great does this garden look now!
The HOTBIN base plate
Hints and tips on the HOTBIN base plate
We get asked if you need to clean out the holes in the base plate – the answer is no.
It is normal for the holes in the internal base plate (ie the black plastic plate, fig 10 (in the bottom of bin) to be covered with compost. The plate and holes do not require cleaning out during normal HOTBIN use.
It may appear ‘counter intuitive’ and you may think they must be clear to allow air to flow – but this is not the case – the air flows around the compost particles. The plate works with the compost in and over the holes. Think about it like this – if you spend ages getting all the bits out, as soon as you reload the HOTBIN the holes will be full again. It has to work with them full.
There is only one special case where this does not hold true –
it is rare but you might come across it.
The base plate can clog up with a very gooey viscous liquid – it stops the water from draining through and the air from moving up.
See example of the underneath of the base plate:
The holes in this case were full of a very gooey sludge like material which sat there and did not drip to the base. It effectively plugged the holes with a watery liquid goo – no air could move up and the bin stopped.
We have analysed the goo. We believe it is almost pure humeric substances. These compounds form during composting. Because the molecules are water soluble and very small – we believe they are draining to the base over time (4-6 months). This appears to be worse when the compost gets ‘too wet’ . Because humus absorbs x500 own weight in water water (it is colloidal) it creates a goo (think of this like a heavy clay soil – water is held in a gooey mass). On the positive side – this is black gold (the very best). On the downside it did stop the bin and we can foresee other incidents will occur.
So here are our tips to ensure it remains a very rare event:
1) Empty the bin every 4 months. (More time in the HOTBIN equals more humus draining to the bottom)
2) Before first fill and after each empty, sprinkle a thin (1 cm) layer of wood chip over the base plate (bits will disrupt and help water flow out)
3) Do not add soil to the HOTBIN. (Clay in the soil will make the situation worse)
Is there a quick way to test for the problem without emptying and taking out the base plate? Yes
It is very difficult to see if the waste in the holes is normal or super gooey (i.e. hanging in the holes below the plate and not dripping off)
Take off the door. Push back waste and slowly pour a half a cup of water onto the middle of the base plate. If the water drains down below the holes within 2-5 mins the plate is not clogged, it it just sits on top – then it is blocked.
(Please note if your HOTBIN is working at 60C, by definition the airflow cannot be restricted and the base plate is not clogged).
Managing Multiple HOTBIN Composters
Own two HOTBINs and have lots of waste to compost?
We have customers with two or more HOTBINs and the question which is most often asked is should I run them together by alternating which one I add waste to or do I fill one first and leave it alone while filling the second HOTBIN?
You can do either but we prefer to run concurrently – this way the temperature will stay high in both bins.
Here is short summary of the options for handling two HOTBINS and larger volumes of waste;
Run two HOTBINs at the same time, alternate which bin you fill every few days.
- Set up first bin, get it half-full and then keep adding weekly food/garden waste to top it up
- Set up second a few weeks later, again half fill it and then keep adding weekly food/garden waste to top it up
- Alternate you waste between the two bins
The advantage to this method is that as long as you have enough waste, both units will stay HOT and hence hot compost faster.
Fill one to the top, set it aside and leave it for a month or so. You will note that the waste will quickly drop in volume and after a few weeks the temperature will drop to 40C. Fill the other whilst the first is maturing.
The downside to this method is you quickly lose the fast phase of hot composting and in truth after a couple of weeks the first one is half full again.
3) Focussed use of each bin i.e. one bin for food, the other garden waste
I personally find it easier to add all the kitchen food waste into one HOTBIN. It is easier to keep one HOTBIN very hot. This won’t be an issue with lots of garden waste in summer, but can be an issue in winter with just food waste. I use the second bin for grass or larger garden clean ups. It is less critical if the HOTBIN containing garden waste cools and drops below 30C.
4) Cheat with one HOTBIN for fast cure and one wooden frame for maturing
Allotment owners like this. They can compost down quickly in the HOTBIN ensuring they kills weeds seeds and reduce volume quickly, then they take out and transfer the base layer early (30 days) into a wooden frame and leave it to mature.
We hope this helps but if you do have any specific queries about compost lots of waste drop a line to email@example.com.
Alec is new customer. His son bought him the HOTBIN for a birthday present. Five weeks in he is happily composting garden waste at 120F (50C) – great stuff
However his garden has been invaded with Houttunyia – as fast as he pulls it out, it grows back. What he wants to know is can he compost the roots?
Houttunyia is a plant that grows via rhizomes (horizontal underground stems that strike new roots out of their nodes, down into the soil, and then plants shoot from the stems). Even the smallest bit of rhizome can grow into
a plant. They can spread extremely quickly.
Can you compost the roots? YES!
HOTBIN composting tips
1) Ensure HOTBIN is already operating above 40C – the heat and thermophilic bacteria ensure the rhizomes are fully composted and no longer viable
2) Chop up any large root balls (use spade)
3) Knock soil of f the roots before adding to the HOTBIN as excess soil affects aeration
That’s it, well OK, one more thing…
If you want to be ultra sure it is fully composted, when you take out your compost after 90 days, put it in a bucket/tub and leave outside away from Houttunyia – if nothing grows, job done!
Measuring up for a HOTBIN
If you are looking at buying a HOTBIN composter and you want to see if it will squeeze in a corner this post is for you!
The HOTBIN is about the size of a standard 250 litre (black/blue/brown/green) wheelie bin.
- Outer: 550 width x 625 depth x 1145 height mm (wheelie bin size)
- Base: 450 x 450 mm (unit tapers to base)
If you are measuring it to check it will fit into a gap, you need to give yourself room to lift the lid right up to a position where it will stay up whilst emptying out your caddy, this is in fact one of it’s USPs according to some customers!
It needs 750 mm depth to allow the lid to fully open – see photo
With the lid open, it needs 1600 mm height.
Wriggly Worms in the HOTBIN
Everything you need to know about worms in your HOTBIN!
I have Worms in my HOTBIN, is this OK?
Yes. If you have worms in your HOTBIN there is no need to worry, equally if you have none there is no need to worry.
Worms are not needed in the HOTBIN – the waste will still decompose because bacteria do most of the decomposition. Worms are good – they decompose waste and leave a rich “vermicompost” behind. This worms also deposit a mucus around the gut digestate which some studies show is beneficial to soil fertility.
How do worms get in the HOTBIN – it has a sealed base?
Worm egg casts are often found small pieces of soil or old compost. Worms are often attached to leaf mould. Often the worms and eggs are added to the HOTBIN when the first base layer is set up.
How do they survive the high temperatures?
The HOTBIN quickly settles in temperature zones – hot top, warm middle, cool base (see graph here). Worms and egg casts will not survive above about 35C, but they will often survive in the base layer.
I have opened my HOTBIN in spring and the base layer is full of worms?
This is just a natural population increase from a few eggs. Normally in winter the soil temperature falls below 5C and worms stop reproducing. In the HOTBIN, even the base layer stays at around 10C and there is lots of food. The worms just keep multiplying, so in spring there can be lots of them in the base. It is also very common to have none!
I have worms crawling up the walls and all over the lid – why?
This can happen shortly after set up, when old compost and new waste has been added. The heat quickly builds up. Worms do not tolerate heat above 40C so they look for a way out. Often they will burrow down to the base, but because the heat rises in the HOTBIN they will often move to the side wall and then climb up. Once at the lid they are stuck. There are several things you can do: collect them up and move them into the base (just take the door off and pop then in the bottom), put them onto your soil (cover them over or the birds will have them, depending on you personal views – feed them to the birds, or leave they to fry (due to heat) and let the bacteria turn them back into compost.
I have white tiny thread like worms all over the lid and/or door – what are they?
These are pot worms (enchytraeids) and resemble a piece of white sewing thread a few millimetres long. They occur quite naturally and part of composting process – they do the same job as the tiger worms. They thrive at a lower temperatures and more acidic pH conditions. They also do not tolerate the heat, so you can get a mass exodus.. This tends to happen if you have emptied and anaerobic wet bin, remixed it all and it then starts to heat up. Just wipe them up with a paper kitchen towel and place on top of hot waste – they will be compost within hours.