Aerobin is designed for year round aerobic hot composting. Hot composting is
desired because it kills pathogens, inoculates weeds and their seeds and
creates good quality compost in a short period of time. Aerobic composting also
dramatically reduces greenhouse gas emissions and bad smells. The bad smell is
the greenhouse gas methane that is 21 times more potent than CO2
little helpers are also known as beneficial bacteria or thermophilic bacteria
(heat lovers) quite simply because they benefit us when we aerobically compost,
as they are the engine room of the compost process. They are smaller than the
eye can see, but work wonders in the right conditions. Like us they have basic
needs to live and thrive - air, water, a comfortable (hot) climate and a good
balanced diet. So everything you do with your Aerobin should be aimed at making
their life easy.
provides an optimum environment to support aerobic micro-bacteria and aerobic
composting. A centralised lung delivers air, a drainage floor ensures the
biomass doesn’t become saturated and insulated walls stabilise temperature by
keeping it warm during colder months and ensures it doesn’t overheat and dry
out when it’s really hot. All that is needed is to provide a good balanced diet
of compost materials (the biomass) to feed the hot microbes and deposit it in a
way that doesn’t smother the pile or block free drainage.
do we get the beneficial microbes in our bins? They are everywhere in varying
amounts depending on how suited the environment is to them. As mentioned, the
Aerobin provides the right environment, so you just have to add the right food.
Initially this needs to be quite precise so the ideal conditions are present
for the beneficial bacteria to thrive. A sure way to get the compost going
quickly and strongly is to add active compost from elsewhere as a kick-start.
This can be from existing compost you have or from compost material purchased
from a local nursery – just make sure it is live and not sterilised.
balanced diet is essential to good health and also good composting. The more
balanced the biomass, the more microbial activity, and the easier it becomes to
manage the composting efficiency of your Aerobin. When there is a lot of
microbial activity the compost is more robust and a wider range of material can
hot composting is achieved with a balance of Carbon: Nitrogen in a ratio of
30:1. This is hard to visualise but in general garden and household organic
waste contains a larger amount of carbon and a smaller amount of nitrogen.
Household waste usually has higher nitrogen content. For example mixing even
amounts of kitchen waste and leaves achieves close to the ideal balance. See
the recipes at the end of this article for more detail.
like us the hot microbes love variety. Too much of the same thing can just slow
them down, or even stop them in their tracks. The surest way to avoid
overloading the biomass with too much of one thing is to mix it up as much as
possible. This gives a choice to the microbes and avoids concentrations of
material that may not help the balance of the biomass within your bin. A good
mix also means that moisture levels are not going to be too extreme and air is
available through the biomass. There are two ways to add variety. All mixed up
like a salad or thin layered (5-10cm) like a lasagne.
microbes prefer to be in a moist environment. The material added to the bin
should be moist to touch like a squeezed sponge or mop. If the biomass is too
wet, aerobic bacteria can’t breathe and anaerobic bacteria take over. If too
dry, the microbes dry out stagnating the compost. Like us they like to drink
and continue to breathe. As mentioned the Aerobin has a drainage floor and this
ensures the bin doesn’t get too wet. The Leachate (liquid nutrients) collected
in the Leachate Tank is a prize for your garden and can be collected and
diluted to benefit pot plants, garden beds and lawns – diluted 20 parts water
to 1 part Leachate.
Odours can tell you how your compost
is working and whether the beneficial hot microbes are thriving.
If there is a fresh earthy smell
this means the composting process is going well. The biomass will be moist but
not too sticky with air gaps. It will give off heat and the beneficial hot
microbes will be thriving. It may even smell sweet.
If there is no smell this means
nothing much is happening and your compost pile is either too dry, or there is
a layer or more creating a physical barrier to the airflow, moisture and
circulation of the hot microbes. You will need to remix this compost for more
balance and variety. Make sure the ingredients are moist like a squeezed sponge.
Add higher nitrogen materials like lawn clippings or kitchen waste or fresh
leaves or increase with water if simply too dry, particularly if there isn’t
any of the “wet” materials readily available.
C. Rotten Egg
Rotten Egg smell means anaerobic conditions
exist and there is too much moisture and nitrogen rich material present –
anaerobic composting is taking place and the result is detrimental to the
environment. Again you will need to remix this compost for more balance and
variety. Empty the contents on the ground and spread out to reduce saturation.
Then mix the contents with scrunched balls of newspaper and cardboard or dried
lawn clippings and loose dried leaves until the mixture is moist like a
squeezed sponge. Ensure the drainage holes at the bottom of the bin are clear.
Cover the base of your Aerobin with a layer of dry material such as sugar cane
mulch or coarse dried and loose leaves to reduce the likelihood of blockages
occurring again. Then place the compost mixture back into the bin.
Like life, composting has basic
needs of air, water, food and a stable temperature. Aerobic compost is a living
process, namely the beneficial heat loving microbes. They are the little
helpers that create good compost and everything we do in managing aerobic
composting is aimed at making their lives easier.
Composting has been with us for
thousands of years – Aerobin is simply a device that provides the perfect
environmental conditions for sustainable static aerobic composting 12 months of
the year. All you have to do is ensure that you get started well and then
continue to serve a balanced compost salad or lasagna to our microbial friends.
Good luck and
1. Load in a
10cm layer of either dry leaves or sugar cane mulch or similar. This protects the drainage floor from
blockages while you start your compost and is particularly important if you add
lots of wet material such as kitchen scraps initially.
2. Seed your bin
with beneficial bacteria by using active compost from either another composting
bin or via your local garden center or nursery (make sure that it is not
sterilized – you can tell because it should feel moist and warm). This will add
healthy levels of microorganisms to your Aerobin.
3. Mix the
seeding material in with material you are adding such as leaves.
4. Begin adding
material in thin layers or pre-mixed.
B. Loose Dry Leaves (lower nitrogen) and loose
grass cuttings (higher nitrogen)
leaves are loose, dry and not compacted.
Mix 2 parts leaves to 3 parts lawn cuttings. Mix together before adding,
or layer alternately 4cm of leaves and then 6cm of lawn clippings. Lawn
clippings can be substituted with the same quantity of kitchen waste. Or
ideally add 2 parts grass and 2 parts leaves then add 1 part vegetable waste
for extra variety.
C. Fresh Leaves (lower nitrogen)
With fresh leaves, it’s important to not over saturate the pile, so we
need to add more dry material and a bit more nitrogen. Add equal amounts of
fresh leaves, dry leaves, lawn cuttings and kitchen waste. Layer in 5-10cm
layers or pre mix for best results. It works well if you intermittently place
100-200mm strips of cardboard vertically in the pile to create air pockets, however
this is more desirable than essential.
kitchen vegetable scraps (higher nitrogen)
Every time you
achieve a 10 cm (4 inches) layer of kitchen waste then cover with a 5cm (2
inch) layer of dried leaves, or 2.5cm (1 inch) of sugar cane mulch can be
substituted for dried leaves. Or mix 1 part scrunched up balls of paper into
the 4 parts kitchen scraps. Again alternatively place 1 part cardboard in 100mm
(4 inch) long strips vertically in the pile to 4 parts vegetable waste and this
will help create air pockets as well.
kitchen scraps can be tricky when starting your bin. Ensure your drainage floor
is well covered with some dry, freely draining material such as sugar cane
mulch. Seeding your bin with some active compost can really make a difference
too! (see Kick Start section above). Otherwise you will need to be careful to
get the balance right until your compost is “cooking”.
and cardboard (very low nitrogen)
and in good balance with other materials, as paper and cardboard has low
nitrogen content. It can be used to augment all the above recipes, and is
particularly useful for creating air pockets. Generally only mix this in small
amounts and never apply in layers.
Waste (slightly lower nitrogen but usually too wet)
generally moist and a little low in nitrogen. Combine 1 part fruit waste with
one part kitchen waste for extra nitrogen and 1 part dried loose leaves to
(high nitrogen and sometimes too wet)
Manures can be
good for compost, particularly Horse Manure and Rotten Cow manure. When dealing
with manures, be careful to balance moisture as well as nitrogen as both are important.
manure/rotten cow manure: mix 3 parts manure to 1 part dried leaves.
manure: mix 1 part cow manure to 1 part wood chips or 1 part loose and course
mix1 part sheep manure to 1 part wood chips or 1 part loose and course dried
mix 3 parts stable manure to 1 part fresh leaves and 1 part scrunched paper or
mix 1 part chicken manure to 1 part paper and cardboard and 3 parts fresh
leaves. Substitute 3 parts leaves with 1 part fruit waste
It is common to
have large amounts of paper and garden waste on the weekends and kitchen waste
during the week. To maintain more balance, store paper, leaves and cardboard
near the Aerobin on the weekend so it can be added evenly during the week. If
your garden produces lots of leaf and lawn materials, try to store them to one
side so they are added in even amounts with vegetable waste.
Don’t add glossy prints or magazines as this may
contain toxic pigments
shells or bulky items are crushed or broken up.