Smallholder Composting: Can I Compost Alpaca Manure?
HOTBIN owner Clare has a smallholding with 50 chickens, 6 alpacas and is now about to open a cattery (www.clarescattery.co.uk). Following her success with her first two HOTBIN compost bins, she has asked us a number of “smelly based” questions over the past couple of months, the latest of which is HOTBIN’s ability to compost alpaca manure.
Clare asked us:
- Can I compost alpaca manure?
- Can I compost chicken poo with my food waste?
- Can I compost cat poo?
- Should I have separate compost bins for the alpaca, cat, and chicken/food waste?
Let’s begin with a cute picture of an alpaca before getting down and dirty with the issue of composting alpaca manure and other animal waste. Hopefully you are not feeling queasy and are ready to read on!
Can You Compost Alpaca Manure? (or Llama poo – its related cousin)?
The answer is yes. All animal poo (including dog and cat poo) can be composted. Clare has been successfully composting alpaca poo for 6 months in a HOTBIN compost bin. She reports just how easy it is: “The alpaca manure is largely free from any bedding additives, save for a bit of hay. I find that alpaca poo composts in no time at all, in fact many people say they use it neat, shall we say, as alpacas are ruminant animals and therefore poo is almost compost as it comes. However, I still prefer to compost it for a short while at least.”
Can I Compost Chicken Poo With My Food Waste?
Yes, chicken poo makes great compost fast. However the addition of bedding from chicken coops/houses can slow the composting process down so you may need to watch the amount of wood shavings added.
Different bedding materials compost at different rates: paper is the fastest followed by straw, sawdust and wood shavings. If you are using ‘pellet bedding’ – this can be either paper pulp or sawdust based. If you want to know more about the science of how lignin and surface area affect the speed of composing visit our woody material post.
Chicken poo is so fast to compost it acts as a compost accelerator and is more cost effective than commercial accelerators.
Can I Compost Cat Poo?
Yes, although many compost websites categorically say no to cat poo composting. There are however some health and safety issues to consider, but in our opinion with a correctly operating HOT home composting bin the risks are small. We do however broadly agree that adding cat poo to a cold compost heap should be avoided.
Should I Use Separate Compost Bins for Each Type of Waste?
We see no reason to separate the different wastes into different compost bins however the options below will give you some advice to make you own decision:
For a smallholder such as Clare we have two options to consider:
1) Separate the wastes into different HOTBIN’s, one each for food waste, alpaca manure, chicken poo and finally cat poo. This is essentially what Clare does now.
2) Mix all wastes together and fill the bins in rotation (e.g. bin 1-day 1; bin 2-day 3; bin 3-day 5; bin 4-day 7; bin 1-day 9 and so on).
We favour option 2 because it is easier to keep the temperature high (60C) with a mixture of wastes (soft, hard, green brown, etc). The easy to digest waste (e.g. alpaca manure and chicken poo) will help the harder waste (shavings and pellets) to rot down. There will also be less wood in one bin so it’s more likely each bin will compost at the same rate. You could set up a ‘square’ of four bins and ‘fill by rotation’, which would keep all the composting in one place and help reduce the heat loss as there will be less wall area exposed to wind chill cooling.
Method 1 would be better if you wanted separate compost, for example just “alpaca compost”. This option also suits separate locations – e.g. (for Clare) a bin by the cattery, chicken pen, alpaca field, and one near the kitchen door.
Whichever method is chosen keep an eye on the temperature and if they are not getting to 60C regularly then adjust the mix.
10 Interesting ALPACA FACTS
- The alpaca is a ruminant with three stomachs; it converts grass and hay to energy very efficiently, eating far less (as a percentage of its body weight) than other farm animals.
- Alpacas do not eat their afterbirths. Clare added 3 into the compost bin and they sent the temp dial spinning! No need to be squeamish about these things, it is what nature is giving us – thanks mother nature!
- Alpaca poo benefits from the addition of a bulking agent to improve its porosity. It is too heavy and dense to allow air to flow evenly through the mix.
- Raw (non composted) Alpaca manure is lower in organic matter (most of the plant cellulose id digested) than the manure from most other farmyard livestock (cows, horses, goats and sheep). Alpaca manure can generally be spread directly onto plants without burning them. Like all manure it is best to hot compost it as this reduces faecal pathogens and converts the organic matter to humic substances.
- The nitrogen and potassium content of alpaca dung is comparatively high, an indication of good fertilizer value. Nitrogen, phosphorus and potassium are the major plant nutrients. (They are the familiar N-P-K on fertilizer bags.
- South American Indians use the alpaca waste for fuel and local farmers apply alpaca’s droppings as a fertilizer when growing fruits and vegetables.
- A herd of alpacas consolidates its waste in one or two spots in the pasture, thereby controlling the spread of parasites, this also makes them popular pets and easy (ish) to housetrain (allegedly!).
- Alpacas originate from South America and have a life expectancy of around 20 years.
- Alpaca fibre lacks the roughness of some other types of wool, so is a popular material for making jumpers, socks, gloves and many other forms of clothing.
- The Alpaca is classified in the same animal group as Camelids, with Camels and Llamas as close family relatives.
Can I Compost…?
Got a question on what you can and can’t HOT compost? The HOTBIN composting team get all sorts of questions on what can be composted and how best to go about it – View our What Can I Compost Lists.
HOTBIN is diverting food waste
Waldringfield Community Composting scheme is successfully diverting food waste from landfill.
Last weekend we visited our friends at Waldringfield Community Composting to look at the results of the first 3 months of the HOTBIN use.
Everyone was keen to learn how much food waste the 12 households had actually diverted from landfill. The results are in and the weighing scales revealed: 5 Kg/week per household. (It was much higher in the B&B – but they have guests each week which accounted for the 10Kg/week.)
What a marvellous community composting effort.
How does this compare to other customers and the national picture?
Nationally the WRAP figures indicate that 5 Kgs per household per week is the average – I’m sure they will be happy to learn they are normal!
Our own HOTBIN customers survey is less rigorous in terms of weighing exact amounts, but it also indicates HOTBIN users divert around 3-6 Kg of food waste per week from landfill The main difference is between users who choose to really get stuck into what you can hot compost such as cooked food waste and chicken carcass etc. versus those that choose to only compost vegetable peelings.
What does all this mean? Does it make a difference?
If we take all the HOTBIN customers across the UK, the total diversion is still not that huge but as they say from little acorns….
There are 30 million households in the UK, if just 3% actively composted all food waste at home, that would remove 250,000 mt of waste from landfill. That also happens to be about the same amount of waste 10 major anaerobic digestion facilities to be built would process.
Clearly it works in our favour if more people have a HOTBIN but the figures speak for themselves!
What does this mean in terms of garden compost?
Each household is also composting garden waste. A total of 250-500 Kgs of starting material will give 75-150 Kgs of compost which is 5-10 bags of compost a year. That’s saving around £25-50 (maybe £10 more if we include car petrol) over buying from the garden centre.
Are there other benefits?
Yes. There are two huge, almost hidden, benefits of composting:
- More food waste results in more compost. More compost results in more humeric substances. More humeric substances means more fertile soil which means stronger plants and vegetables which in turn means more and better food.
- Humeric substances are ‘recalcitrant forms of carbon’ – they are resistant to further decay so they store carbon in the soil. Adding stable humeric substances to the soil results in carbon sequestration which off-sets the impact of global warming due to CO2.
What could be simpler, compost more!
How to compost grass lawn mowing
To get fast superb results when composting grass lawn mowings in the HOTBIN:
Add 40 parts grass with 20 parts shredded paper and 1 part wood chip (bulking agent)
Typically this is a medium sized lawn mower collection box (40 litres) with a full carrier bag of shredded paper (20 litres) and 4 hands full (one 2-litre measuring jug) of bulking agent.
If you want to view a photographic sequence of grass compost stages, you can jump to our post on steps / stages of grass composting.
Below we explain why this recipe works, why just adding large amounts of grass can be problematic and offer 6 different options for handling large volumes of grass cuttings
The problem often seen when composting grass is you end up with a black slimy layer that stops the compost heap working.
In a HOTBIN you should get brown mulch in 7 days
Grass is one of the quickest materials to compost. In the HOTBIN you can typically convert grass to mulch within 7 days. Grass is so quick to heat up to 60-70C, the HOTBIN team recommend it to help accelerate and increase temperature quickly.
BUT! You can end up with a black anaerobic slime
In traditional compost heaps, it is one of the most troublesome materials to compost. Grass often heats up for 2 days and produces a very distinctive whiff (ammonia/urine). After 2-days it then ‘collapses’ into a cold, wet, slimy black mass that smells horrible (anaerobic mush).
Funnily enough we don’t have a picture of this as if you do it correctly in a HOTBIN it shouldn’t happen!
Composting grass successfully requires a little bit of extra composting knowledge but the real secret is matching the amount of grass you generate with the time and effort you have available.
Why does grass turn into a slimy putrid mess?
The ‘black slime’ is due to anaerobic conditions, i.e. excess water and too little airflow. Grass (lawn mowing) has a high water content (>80%) and no lignin (i.e. no woody stalk). As grass starts to decompose, the plants cells break down and become soft; water is released. The grass collapses and forms a thick impervious layer and airflow decreases. This in turn means the water is trapped, the process slows and a vicious circle is created where water is not removed, all oxygen stops flowing and aerobic bacteria cease to release heat. The heap cools and anaerobic bacteria take over releasing obnoxious odour and resulting in a ‘black slime’.
The golden rules for successfully composting grass are:
- Remove excess water
- Keep the grass aerated
- Balance the mix to avoid ammonia odour
So how do we get rid of excess water, keep the waste aerated and avoid both ammonia and or anaerobic odour?
- To remove excess water
You need lots of heat, i.e. you need to be ‘HOT composting’
- To keep the grass aerated (i.e. get air/oxygen into the grass layer)
You need buoyant airflow which requires a temperature gradient and a structure with spaces and gaps so the air can flow up.
Unless you have the means to force airflow (e.g. a pump / blower), or you can constantly turn/tumble (yes we mean constantly), then you are reliant on “buoyant airflow via the chimney principle” – and this requires the grass to maintain a structure with small air spaces (ie not a thick wet slimy mass!).
To get a structure that stops grass collapsing into a slimy heap, you need to add what we refer to as a bulking agent (typically this is wood chip). The bits of wood chip act like ‘stacking blocks’ and the air flows around them. Simple but essential!
- To avoid ammonia odour
To prevent excess ammonia, you need to be adding a fast/easy to digest carbon material like shredded office paper or chopped up corrugated cardboard.
The odour is caused because grass has an excess of nitrogen which the bacteria are unable to use as fast as it is released. So it forms ammonia gas and evaporates away. You are most likely to notice this when composting and/or turning large quantities of 1-2 day old grass lawn mowing. After 3 days things slow down and the nitrogen is no longer in excess. Turning grass heaps does not prevent the odour – it enables the trapped gas to escape ‘all in one go’. (If you have done this job, you may well come back inside the house and realise your clothes smell of ammonia!).
The HOTBIN does have an odour filter in the lid that does remove ammonia odour. But, when you add a whole box of grass in one go without anything else, the filter gets temporarily overload for 2-3 days. To prevent the odour during the initial 2-3 days you need to balance the carbon/nitrogen ratio.
You achieve this by adding a dry high carbon waste. The key here is to add ‘easy to digest carbon’ such as corrugated cardboard or paper shredding. Woody items like sawdust, shavings, wood chips are high carbon – but they are not easy to digest, so will not balance the C/N during the critical 2-days of intense activity. Here is the challenge – you need a lot of dry carbon! A 40L grass box (a typical mower box), needs 20L of paper – that’s a whole carrier bag full. It also needs to be mixed with the grass. Not everyone wants to do this, especially after cutting the grass. Below we outline a few options about different methods you might want to follow.
Large amounts of grass waste need extra steps to compost quickly, without ammonia and without turning putrid. Is the extra effort worth it? We think so! Each year fertilising grass lawns consumes considerable inorganic fertiliser – adding the nutrients back via compost is environmentally better.
Below are six options/choices for composting grass. Often you can ‘mix ‘n’ match’ routines at different seasons and times of the year to cater for the varying grass volumes.
1) Small to medium lawns – add grass into your HOTBIN each week
The HOTBINn will easily compost grass from a small-medium lawn (approx 40 litres/week or 1 large grass box per week, filling about a quarter of the bin each time).
This will generate some odour that you may well notice for 2 days. If this bothers you, there are a couple of methods to solve this:
- add shredded paper or corrugated cardboard in ratio 2 parts grass to 1 part paper
- Only add half a box, then return 3 days later add the other half
|Grass volume / Weight
||To Avoid wet slime
||To Avoid Ammonia
|40 litre (approx 20 Kg)
||Add 2 litre (a measuring jug) of bulking agent. Mix in well
||Add 20 litre (a full carrier bag) of shredded office paper or chopped up corrugated cardboard).
Results in approx 1.6 Kgs of compost in 30-90 days
2) Large lawn – use a dedicated HOTBIN for grass
If you have a large lawn and generate 3, 4 or more boxes each week, then you will need to consider a dedicated HOTBIN. It will cope with 2-4 boxes (about 60-80L) per week.
The same rules apply – but adding and mixing in large amounts of paper is intensive and requires a high degree of commitment – perhaps not what you want straight after cutting the lawn! Large lawns allow the HOTBIN to be located away from your seating area – so we suggest you save your effort of adding shredded paper to eliminate ammonia odour – just leave the HOTBIN down the garden and reap the benefit of fast compost without anaerobic slime.
|Grass volume / Weight
||To Avoid wet slime
||To Avoid Ammonia
|80 litre (approx 40 Kg)
||Add 4 litre (a measuring jug) of bulking agent
||Leave remotely and accept ammonia for 1-2 daysAdd 40 litre (a full carrier bag) of shredded office paper or chopped up corrugated cardboard).
Results in approx 1.6 Kgs of compost in 30-90 days
3) Leave the cuttings to compost on the lawn
Many gardening sites now actively promote leaving grass cuttings on the lawn. Normally you use an adapted/special mower blade that chops the grass into very small pieces (2-5 mm) and thoroughly spreads them. The method is to weekly trim of top third of grass and spread this evenly so it composts quickly, adding nutrients back to soil, but not creating thatch. If you have the grass ‘trail line’ down side of mower, then this will rot into mulch that blocks light and growth and does create thatch. Please refer to manufacturer for correct mower blades/settings. If you walk regularly on your lawn – you may find bits get on your shoes and are walked back into the house!
4) Best of both worlds’
Add the first few cuts of the year which tend to be large (say 3-4 boxes) into your empty HOTBIN. The bin is full for a week or so, and then rapidly becomes half-empty allowing ongoing use with food. After the spring cut, leave grass cuttings on lawn. Occasionally (e.g. when cutting hedges) add the grass box back on the mower and collect grass to complement garden ‘browns’.
5) Transfer grass to Local Authority
This is unlikely to interest HOTBIN users, but it is possible to have grass collected at the kerbside and taken to the council recycling centre. We are strong believers in home composting and believe in the environmental benefits of saving fuel and transport.
6) Allocate a large, remote area of garden to build smelly grass mounds
The mounds will tend to be smelly and go anaerobic, but it is fast to empty and dump lots of grass. We had rave reviews on how fast and efficient the HOTBIN is with grass – so maybe you do not need this option anymore!
So in essence it is easy to compost grass in your HOTBIN but depending on the amount you need to consider which methodology is best for you.
DON’T get into HOT WATER
KICK STARTING the HOTBIN
The temperatures have dropped again and some of us may be expecting snow this weekend. Here is a quick reminder why you actually get a ‘(HDPE) plastic bottle’ with the HOTBIN with extras.
New customer, Phil, wanted to know if he could use two 2L bottle rather than the one 2L bottle we supplied to get a super fast start.
The answer is yes…but we forget to remind him that the ‘KICK START HEATER’ supplied is not just any old plastic bottle but made from High-density Polyethylene. Unfortunately you CANNOT use coke bottles (made form PET), plastic milk bottles (LDPE) or glass. PET will melt (see picture), glass can shatter when taken into the cold and or if you slip, and the very thin walls of milk container plastic will deform. There are not many H&S risks when using the HOTBIN – but taking care with using boiling water with the ‘Winter Heater’ is one of them.
Why is two good?
The basic idea is to add enough heat to get the central waste to 20-30C for a few hours.
Each litre of boiling water (at 100C) has 4200 Joules of heat energy. Double the Litres = double energy transfer = more heat in waste = more chance of bacteria getting warm and active.
If you are doing 2 – the secret is to get the lids on and then get each bottle into the bin super fast – leave the bottles standing for even a few minutes and half the heat will be gone.
See our WINTER post for more detail. Another top tip is to add the Hot Water Bottle twice in succession if you want a bigger boost.
What happens to PET plastic bottles if you add boiling water
Have you got an insulated compost bin?
How to challenge the marketing waffle and avoid buying a duff ‘hot composter’
This post is one of a series that help explain hot composting and how to choose a hot composting bin that performs in a domestic environment.
We are seeing an increasing number of articles on hot composting and more and more compost bin suppliers describing their compost bin as ‘insulated’ or ‘heat retaining’ to help you achieve faster composting and even hot composting. There is good news and bad in this – good that there is an increasing recognition that hot composting can be achieved at home in your back yard, but also a worry that some of the claims on hot bins are ludicrously misguiding buyers. The basic laws of nature (Newton’s law on cooling and the biological rate of heat production per kilo of food/garden waste) do not support most compost bin designs ever retaining enough heat to rise above ambient (air temperature) never mind get into the hot composting 40-60C range.
If you want to hot compost we suggest you read below and familiarise yourself with science and choose your hot bin carefully. Look for one with a clear application of science to create a design that works. If you do not have the time or expertise to do this then read the article below as our advice is simple. Search for customer reviews and testimonials – but look beyond the ‘it arrived and I have set it up’ type review that appear on many shop sites, search explicitly for “compost reviews 60C”, “compost bin that works at 40-60C”, “I am hot composting” “my temperature gauge reads above 40C”, “I have reached 60C”, i.e. hot temperature in my compost bin”
The HOTBIN team spent 2 years analysing why various compost bin designs failed to deliver hot composting. Once we had the engineering solution for what would work we set about figuring out how to make it cost effectively. There are over 200 compost bins on the market. To date we still have only found 5 domestic compost bins worldwide we believe genuinely offer a realistic chance of hot composting in a domestic environment. They cost respectfully: £900, £550, £250, £185 and £175. Prizs for which is the HOTBIN!
Here’s the science and engineering you need to choose a hot compost bin:
Newton’s law of cooling – hot moves to cold until a balance (equilibrium) is reached. A cup of hot tea always cools to your room temperature. Leave it outside in the snow and it will eventually freeze. A compost heap follows the same law – all heat produced by the bacteria moves from the hot centre out to the cooler outside air. You cannot stop this, all that can be changed is the speed at which the heat lost occurs. Put your tea in a well insulated thermos flask and it will stay warm all day. Forget to drink it and return next day – at best it will be luke warm.
A very thick insulated material will slow heat loss – but this is very different to using the term “insulated” because it uses a thin insulating material (plastic). Know your facts – challenge the supplier – as for their scientific evaluation (evidence) and ask for customer reviews that prove they are hot composting (i.e. achieving 40-60C)
Here’s a quick comparison of several compost bin materials and how thick they need to be to have equal insulation value:
|U ValveMeasure of resistance to heat flow per m2
U valve is used by the building industry to stop you getting ripped off when buying roof insulation
|50 mm wall of expanded polypropylene (EPP)
||This is what the HOTBIN is made from – 50mm thick EPP walls
|To achieve the same insulation (U Value) – ie to slow conductive heat loss to the same level –below we compare how thick the walls of other compost bin materials would need to be
| 500mm thick of wet wood
||That’s about 5 railways sleepers wide! Pallets are 20mm thick wood.
|= 700mm of compost
||A pallet frame is about 1m wide. 500mm each side of a really big heap. Only the very small centre is likely to stay warm. Be prepared to turn all the outer compost into the middle!
|= 600mm of High density polyethylene
||Most compost bins have HDPE walls 2-3mm thick). Image a bin with 0.6mm thick plastics wall!! (Plastic dalexs keep the waste together and offer some protection against wind and rain. They do not “thermally insulate” your compost heap.
|= 50mm of foamed LDPE
||LDPE foam insulates as well as EPP. Most PE foam is floppy and costs significantly more to mfg. Rigid foamed PE board is available – we have only found compost bins with 15mm thick walls – i.e. 5 times less insulation than the HOTBIN.
|= 50mm of PU foam
||Most PU foam boards are ‘open cell’ which means they absorb rain water or steam/water from compost. They will be wet and cease to insulate within a few days.
If you have a very big garden with lots of waste – build a big compost heap (>2m*2m*2m). It will stay warm in the middle for a period of time. Turn occasionally to move the outer cold, non composted waste into the middle. This is what industrial composters do in their ‘windrows’ composting and it is the system largely designed by Sir Howard back in 1930s that forms the backbone the ‘New Zealand 3 bin rotation system’. Not many have this amount of waste, or the time and energy to turn this much material.
Now you know you need to look at thickness and the thermal insulation of the walls (i.e. obtain the U value). However heat is also lost by convection. Air moves within the compost (at last we hope it does otherwise it will go anaerobic and smelly very quickly!). Moving air transfers heat very fast. Winds can cool things 100 times faster than still air. Go out in a cold wind with no clothes on and you will suffer hypothermia very quickly due to ‘wind chill’. Your compost heap is the same, it loses heat as cool air flows over it and carries warm air out.
We have discussed conductive and convective heat loss and the need to minimise it to have a reasonable chance of achieving hot composting by using insulated walls, sealed lids and airflow valves. There is one other important piece of science we have to adhere to – the first law of thermodynamics: energy and matter can neither be created nor destroyed, all we do is change the form. Focusing this down to the relevant bit; the total energy (heat) going in (from food as calories) must equal the total energy going out (i.e. heat lost).
There is a bit of chemical engineering science that looks at amount of energy available from bacteria composting each Kg of food waste, how much is lost as heat due to convection and conduction. It also defines how much needs to be retained to keep the compost above ambient (i.e. at 60C rather than air temperature at 10C. This law is the bit most compost bin designs convientely ignore and or fail to explain. Most households do not have enough waste (i.e. energy going in) to keep warm due to the amount of heat being lost.
The average house produces 5Kg of food waste a week (and maybe 10Kg -20Kg of green waste during the summer gardening season). The HOTBIN will stay hot with 5-10Kgs of waste a week. The maths are straight forward – most other compost bins lose heat so fast they need 50-100Kgs per week going in to keep warm. If you have this much waste, you can copy the hot system used by industrial composting – build big heaps 2mX2m, get a tractor and turn the waste.
Even the very best hot composting systems designs have a minimum amount of waste that needs adding each week to keep things hot. We find around 20% of HOTBIN customers struggle to hot compost and by far the biggest issue is these users who do not have the minimum amount of waste to hot compost. Garden Organic tested the HOTBIN against a leading plastic compost bin claiming to hot compost. The science explains why many compost bins can be loaded with 200-400 litres of waste in one go, they get hot for a few days and then cool. The science also explains why such bins are unable to heat up or stay warm when 5Kgs per week of food waste is added.
The HOTBIN does what is says on the BIN – it will stay hot all year at 40-60C with typical volumes of waste from a 4 person household (i.e. 5Kgs per week).
HOTBIN – it does what is says on the BIN
HOTBIN believes it has used nature’s laws of science to design a compost bins that work and explain why many others will more often than not fail to warm compost never mind hot compost. We neither want to overstate (or understate!) how the HOTBIN or any other product works.
Can I compost Horsetail (Mare’s Tail or Equisetum Arvense)?
Yes you can compost it. BUT!!
Problems will arise if the heap does not get above 40C – the seeds will survive cold composting and you will spread the seeds when the compost is used. A hot compost heap (40-60C) will kill the seeds.
However as this is such an invasive and tough weed, you need to check that the seeds/bits are only added to the top of a already hot pile, that they stay near the top (do not fork in or turn the pile/HOTBIN as seeds will fall down to cooler base). Finally, after hot composting, give your compost a ‘germination test’ – By this we mean leave the compost in an open maturation pile for a few months to check to ensure the Horsetail does not re-sprout. If it does, gently tease out all roots and rhizomes again and zap it through the hot compost again.
This may sound painstaking – but so will your efforts to remove it from soil in the first place. Are there any other options? Passing the waste on to your local authority to handle is not a great option. The seeds and bits can drop and disperse on roads and neighbours plots. If you are unsure, perhaps this is one case where it is better to burn the weeds (subject to local authority rules of course!).
- Horsetail or Mare’s Tail (Equisetum Arvense) is an invasive, deep-rooted perennial weed with fast-growing rhizomes (underground stems) that quickly send up dense stands of foliage that will spread quickly to form a dense carpet of foliage, crowding out less vigorous plants in beds and borders.
- Horsetail is easily recognised by its upright, fir tree-like shoots that appear in summer. In spring, fertile light brown stems, 20-50cm (10-20in) tall, appear with a cone-like spore producing structure at the end of the stems. In summer, sterile green shoots develop into fir tree-like plants, 60cm (2ft) tall.
- The creeping rhizomes of this pernicious plant may go down as deep as 2m (7ft) below the surface, making them hard to remove by digging out, especially if they invade a border. They often enter gardens by spreading underground from neighbouring properties or land.
You can also find more advice at: Garden Organic Website
Compost – What Should it Look Like? Looks can be deceptive!
Compost from you compost heap, compost bin and indeed your HOTBIN composter can vary an awful lot.
With many HOTBIN® composters coming up to their first autumn, there will be a lot of hot compost being taken out and used in the garden. We thought it would be good idea to let you know what to expect as ‘looks can be deceptive’!
To do this we will look at several batches of compost alongside some HOTBIN composts. Suggest how they might be graded based on common expert visual assessments. Then we will take you on a journey beyond the first look to give you some insight into compost stability and maturity tests (we’ve done them for you!), discuss what happens when you dry and sieve HOTBIN compost (don’t worry no-one is suggesting you need to do this) and finally do a bit of mud pie play to demonstrate a property called ‘colloidal behaviour’’. Finally we will tie these properties back to humeric substances and suggest that what you really need to look for in fabulous compost is high humeric substance content.
This blog is a little more scientific in nature than some of our others – so if you want the headline without the science it is this:
What a compost looks like can be deceptive. HOTBIN compost is often very sticky and very moist/wet and looks lumpy and perhaps even needing further composting. Tests show rather than it being ‘poorly’ composted, quite the reverse – it appears to have a very high humeric substance content and this is good news for your soil and plants – humeric substance is known as ‘black gold’ for a reason!
If your compost looks like (Fig 4&5), or even (Fig 6) below it is OK to dig in to your soil and does not need ‘more composting’. If you only want ‘fine’ particles of compost e.g. looking like (Fig 1) or (Fig 2) – the solution is fairly simple – dry your compost and then sieve it – you will surprised by how much fine material there is in HOTBIN Compost.
Our analysis tour includes;
1. Visual inspection
2. Carbon / nitrogen maturity test
3. Visual after drying and sieving
4. Pliability / colloidal behaviour
5. Humus test
6. Result to quality – is it fabulous?
1. Visual inspection – Below are 6 samples of compost
- (Fig2) Garden centre compost laid out dry
(Fig 3) Typical cold compost
- (Fig4) HotBin compost at 3 Months
(Fig5) HOTBIN compost that is it too wet
(Fig6) HOTBIN compost that has gone
anaerobicNow in our earlier blog (good, bad or fabulous compost) we outlined details on how different experts defined good compost. If we asked this group of experts to visually judge the samples above here is what we would expect:
(Fig1) Vermicompost – looks fine and rich, super
(Fig2) Garden centre compost laid out dry – looks very fine and free flowing, uniform and has probably been sieved
(Fig 3) Typical cold compost – looks mature, maybe 2 years old and as expected,
(Fig4) HotBin compost at 3 Months – looks ok, dark brown and a little lumpy
(Fig5) HOTBIN compost that is it too wet – looks water logged, lumpy, immature and soggy
(Fig6) HOTBIN compost that has gone anaerobic – definitely looks anaerobic, it’s black sludge not compost
2. Carbon / nitrogen maturity test
Industrial producers of compost (i.e. compost sold in garden centres) do a check to establish how active the bacteria are. Above a certain level and the compost is too active (i.e. not mature & stable) it needs to be left longer otherwise it can draw nitrogen from the soil as bacteria continue to use the carbon in the remaining compost. The maturity and stability test can be undertaken via the Solvita compost test method. You can do these at home, although it gets expensive!
Garden centre compost (Fig2) would not have gone on sale without passing the C/N maturity and stability tests. How did HOTBIN (Fig4&5) compare? Well they both fall in the stable and mature range. This will surprise a lot of experts as they look lumpy and lumpy normally means large pieces of non-composted material which is highly likely to result in an ‘active’ rather than stable result.
3. Visual after drying and sieving
We recently tested a range of compost sieves (see guide to compost sieves post). We know wet and sticky compost is a complete pain to sieve. When testing the Compostsifter it failed to sieve any of HOTBIN (Fig5). So we dried the compost and tried again. This reminded us of an old saying – ‘looks can be deceptive’. Below is the result of the sieving test.
HOTBIN compost sieved
The result was about 80% of all the compost went through the fine (8mm mesh) sieve. There is about 15% of wood chip pieces (0.8-1.5mm), and 5% oversize non-composted items (notably pampus grass roots – these are possibly going to take the record for the hardest most difficult material to compost – but that’s another blog!). I’d just like to say this sieve result is not a one off – we have seen it many times, same results.
If we visually compare the sieved HOTBIN compost with the sieved garden centre compost they now look very similar. So was the problem just that the HOTBIN sample has been stuck in the base and got wet? Is the difference just about one compost being very wet and another compost being dry? No!
4. Pliability / colloidal behaviour
When we sieve and handle HOTBIN compost we notice something else – it is very sticky. It rolls into balls in the sieves, when you grab a handful you can make a ball. It is ‘pliable’ just like a potter’s clay or children’s plasticine.
HOTBIN Vs Garden Centre on compost pliability
There are two common substances in soils and composts that create a pliable mix – clay and humeric compounds. Both these are ‘colloidal’ materials and it is this property and the resultant way they hold water that leads to the pliability.
We can take the pliability test a little further. If we make a ball of moist compost from Garden centre compost and HOTBIN compost (Fig5) and leave then to dry in the sun for 4 days. Now what happens when we try and squeeze each ball?
HOTBIN Vs Garden Centre – compost pliability after drying
The garden centre compost sample behaves more like peat – it sticks when wet, dries fast (i.e. looses water 2-4 times faster) and then the organic material falls apart when the dry ball is pressed. Whilst the HOTBIN sample is still damp and pliable, it forms a very hard solid outer layer material with soft inner. Even after 100% drying and re-wetting the pliability returns.
At this stage we should mention that HOTBIN composting (and certainly the batch of HotBin compost above ) had no soil added – hence the pliability is not believed to be due to soil clay.
5 Humus test
We think (and we mean ‘think’ because we have no laboratory proof) that it is possible that HOTBIN compost has more humeric substances than many other composts.
HOTBIN compost – Pliable humus
Can we test for humeric substances? The answer is yes but not easily outside a fully operational soil testing lab. There is a relatively simple humus soil test – targeted at measuring the concentration of humeric substances in soils. The HOTBIN samples are off the scale – but a note of caution – the test aims to give a reliable field test for soils with 0.5-6% humeric substances. It cannot be relied on for concentrations well above this.
6 Result to quality – is it fabulous?
We believe there is a real difference between compost and compost that contains very high amounts of humeric substances. Partly decomposed material (compost) will continue to decompose when added to the soil and eventually the carbon cycle completes and it is returned to carbon dioxide and a small amount of recalcitrant humus in the soil. Humeric substances do not decompose in the soil (to any great extent) so adding a concentrated form will improve your soil faster.
HOTBIN compost – drying out
As a company we are not into making claims about our products we can’t substantiate – to be clear – we believe we can explain the appearance and behaviour of HOTBIN compost. We believe we can trace (but not prove it yet!) this back to higher humeric substance content in HOTBIN compost. One day we will have the evidence – until then we believe our logic and science has merit, you can do your own testing, contribute to the debate or ignore our findings as just marketing waffle!
Worms and HOTBIN composting
A question we often get asked is; do I need to keep my Wormery now I have a HOTBIN?
The simple answer is no and the key benefit is that the HOTBIN can compost both food waste and garden waste. Therefore you can save space, reduce costs and still keep your food waste out of landfill.
So what is worm composting?
Worm composting is using worms to recycle food scraps and other organic material into a valuable soil amendment called vermicompost, or worm compost. Worms eat food scraps, which become compost as they pass through the worm’s body.
So what is HOTBIN composting?
The HotBin is a simple design that helps maximise what nature does by bringing together the right conditions to make hot composting easier. It does this by providing effective aeration between the bottom air inlet plate and the air outlet rotating valve, removing excess water through the valve as steam and allowing you to control the rate of heat loss. You can compost 100% of all domestic food waste in the HOTBIN without inherent problems with odour, vermin and flies. This includes left over meals, plate scrapings, meat, fish, small bones, bread, cakes, pasta and rice. Your food and garden waste will be turned into rich organic matter for the garden every 90 days.
Worms in the HOTBIN?
You do not need to add worms into the HotBin however you can – either directly by adding into the base layer (which is cooler) or inadvertently by adding worm eggs and worms into the bin via small bits of soil and old compost . Most of the worms and worm eggs will be killed by high temperatures (>45C) but a some will find there way down into the base layer and continue to work on the base layer compsot.
However, worms can be beneficial to composting and can be added if you want to. But a word of warning do not add them into the upper active layer (60°C will kill them) only add worms via the hatch panel where the compost will be cooler. Worms will help to decompose waste and leave mucus in the compost which is proving beneficial to soil fertility.
As the HOTBIN is no ordinary composting bin as you can use it to recycle than just vegetable kitchen waste in it. The hot temperatures achieved during hot composting make composting all food waste in the HOTBIN a safe home composting system that recycles a whole lot more than just potato peelings.
So if you were thinking about a Wormery as a form of recycling food waste why not consider a HOTBIN as it composts both your food and garden waste together.
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!
Can I add Autumn LEAVES to compost in my HOTBIN
Leaves can go in the HOTBIN and they make great humus.
If you have a lot of leaves (>10 litres, a bucket load), you need to tweak the recipe to ensure they HOT compost.
If you only add thick layers of leaves into the HOTBIN, it is unlikely they will rise above 20-30C as the woody nature means they are hard for bacteria to digest and hence heat is released slowly.
To HOT compost autumn leaves, see the recipe below:
How to HOT Compost Autumn Leaves
There are two parts to successful composting of autumn leaves.
1) Adding a nitrogen source to balance the high carbon in leaves
2) Ensuring that there is enough ‘easy to digest’ waste (e.g. greens, food waste, shredded office paper’ (which creates heat quickly) to keep things hot whilst the hard to digest woody material (in which heat is released slowly) are also digested. In some cases solving (1) & usually solves (2).
Here’s what you need to do to ensure you get the best out of your HOTBIN
Step 1: Shred leaves
Leaves tend to form a dense matted layer that restricts air and oxygen flow within the HOTBIN. We advise shredding the leaves (e.g. using mower or a hedge trimmer).
Step 2: Mix leaves with easier to digest materials like food waste
Many people simply will not have enough food waste to mix with high volume autumn leaf fall. You can cheat a little by adding another easy to digest waste to go with the leaves such as chicken poo, chicken pellets, or a sprinkling of blood bone meal.
The ideal waste to mix with autumn leaves is grass lawn mowing – unfortunately, it is rare in UK to be able to get the mower out in Autumn as it is too wet and compacts the lawn soil. If you have room storing leaves in a wire frame box ready for spring and first grass cut can work really well . (Avoid sealing in black bags – the leaves will go anaerobic (see below for anaerobic method).
Step 3 – Do not add too many each time – little and often is best
More than 10cm (20 litres) of cold wet leaves in one go will “stall” the HOTBIN. The cold leaves will lower the temperature of the HOTBIN below 20°C and the heat production falls below that needed to re-heat. So store the leaves in a pop up bag, protected from rain and add over a couple of weeks – you’ll be amazed how fast they compost.
If you have a large garden with lots of trees and mounds of leaves then possibly doing a little bit each week in the HOTBIN is impractical. Try the following – shred the leaves (e.g. using lawn mower), store in a wire frame or cold compost heap until spring. Mix with first grass cuttings in large volume piles. Turn occasionally.
Leaf Mould Versus Composting
If you are collecting leaves into a wire frame then you might go down the route of just leaving them in the box and waiting 1-2 years for leaf mould.
Leaf mould versus ‘bagging’ i.e. anaerobic digestion
Many compost sites note that ‘bagging’ leaves in black plastic and tying off will create a black slime that can be used as compost. What this really means is you are anaerobically digesting the leaves down to compost. To an extent this is ok, our point would be AD creates methane and you are releasing a GHG that is 24 times more harmful than CO2. And we hope you would agree that every little bit avoided helps.
Aerobic composing is carbon neutral. Also to be honest – the black bags absolutely stink when you open then!
You can now successfully compost large amounts of Autumn leaves in your HOTBIN.