Balcony compost

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Balcony compost

Also: Can you put a compost bin on concrete?

OK you’re thinking about making compost out of kitchen waste in your apartment or condo. Specifically on your balcony where you may have a little extra space that’s just outside your regular living space.

We could, if we wanted, go on and on about how everyone should make compost from food waste rather than sending it to landfill sites. This is all very well but to be compliant and make our contribution, however small it may be, we do have to think of the practicalities if we are pushed for space.

So, balcony compost, what are the options? It is doable and can be achieved in a very small space. With a bit of effort and imagination you can generate a very passable compost which will prove valuable, to you, if you’re growing anything large or small.


What composter to buy for a balcony
There are two types of composter which you may consider. Depending on how much space you’ve got on your balcony you could have a small tumbler type composter or a wormery composter. Both have their virtues and will provide a convenient method of disposing of green waste from the kitchen.

If you go along the compost tumbler route you may find  that you will need two compost tumblers so that when one is full you can leave it without adding any more green waste. This will ensure that the contents will all completely rot while you are loading waste into the other tumbler. This may be a little tricky if you’re stuck for space.

Room on the balcony for making compost

If you are wondering if there is a difference between a compost bin and a tumbler, we have a post that compares the two systems. You can see it at ‘Tumbler composter vs bin’ where you will probably agree that a tumbler will be better than a standard compost bin, on a balcony.


What else?

Bokashi composting                 Making compost at home
Making compost fast              Making compost indoors
Making cactus Compost           
Rolypig composter work on a balcony?


Worm composting kit

Another alternative method of making compost on the balcony is to use a wormery. Worms will eat your kitchen waste and convert it into compost. They will not eat fresh green waste because they are not able to digest material that hasn’t started to decompose. They will eat the mould and variety of fungi that quickly appear on kitchen waste in the early stages of decomposition.

As the kitchen waste starts to breakdown the worms will get to work and start feeding on this as well as the mould on the surface. The best type of wormery consists of a chamber of layers.The layer at the top of the stack will have the freshest and newest kitchen waste that is yet to start decomposing and won’t be ready for the worms. The layer at the bottom of the stack will have the oldest material. This is where the worms will be at their most active because this material is what they can eat and consume.

The other layers in between the top and the bottom will be at varying stages of decomposition and the worms will travel from the lowest layer up through the other layers to wherever they can find rotten food that they can eat. 

This system of wormery provides total freedom for the worms. They can move to wherever they want exploring throughout the whole stack to see if there is any mould for them to eat or food that is rotten enough for them but will spend most of their time in the lower area where the most decomposed food is.

The population of worms will build up very quickly and will reach a point where they will convert rotting green waste in to worm compost quickly and efficiently.

This system tends to generate a certain amount of liquid. Modern plastic wormeries have a facility for collecting this liquid which can be delivered into a suitable container via a tap which will be found at the lowest point of the wormery composter. This liquid can be used as a liquid plant feed. It will have a range of nutrients all of which are naturally occurring. It may be necessary to dilute this liquid with water because in a concentrated form it may be too much for some plants. Also if you dilute this liquid it will go further and do more for you.

If you don’t have any plants to use it on but liquid is still being generated, as it will be all year round, you can store the liquid in plastic containers for a short while until it is convenient to use it. Don’t keep it around for too long because the bacteria in the mix will digest and break down the nutrients that you want for the plants. This is very valuable liquid fertilizer and well worth holding on to.

You can make compost on the balcony

Bokashi composting

You may have heard about an in-door composting system that’s known as the ‘Bokashi‘ system. This is a way of processing waste but it doesn’t actually make compost. The process involves fermentation which produces acids that effectively pickle the waste. We have a post that explains the issues, advantages and what is generally involved with the Bokashi system. You can see it at ‘Bokashi soil factory’.

Bokashi composting is something that you can easily do in the confined space of an apartment or condo. Being of Japanese origins bokashi, in the composting context, is an additive that provides naturally occurring bicrobial life forms. When added to kitchen waste a fermentation process begins that breaks down all organic material that’s present.

There are specially made bokashi buckets. These have sealable lids and a tap at the base for extracting the liquid that will be generated as part of the fermentation process that occurs.

The generated liquid is of value as a plant food because of the highly available nutrients that are released in the fermentation process.

When the bucket is full you need to leave it for about a week for the fermentation process to fully complete throughout the entire contents. For continuation of the bokashi process you will need a second bucket to have somewhere to dispose of the ongoing supply of waste.

Making compost at home

Making compost at home is actually one of the easiest things you can do. All you need is a suitable container. Most compost is made outside in the garden using either a static bin or a compost tumbler. If you’re doing it this way there is usually enough room depending on the size of your garden. 

When you’ve decided on which system you want, all you have to do is to keep adding your green kitchen waste as when it’s available. Make sure you had enough carbon based material to balance the green kitchen waste. For the carbon based material you can use  shredded newspaper or cardboard. The cardboard can be from cornflake packets or any other packaging where cardboard is used. The aim is to achieve a balance. If you’ve got too much of one thing and not enough of another the outcome may not be the quality of compost that you would like. You need to study the compost occasionally, if it looks wet and it smells take this as an indication that you need to add more shredded newspaper or cardboard. This will absorb excess moisture and help to keep an open texture in the compost as it’s being formed. Doing this will allow air to get into the mix which will accelerate the decomposition.

Making compost fast

 In my experience using an accelerator can sometimes make the compost mix a little more acid then you may like. If or when this happens you will noticed that the mix looks wet and stodgy. You will find a positive improvement if you add hydrated lime. This will do much to neutralize the acids that may have been formed. It will also reduce any pungent smells that may be emitted as a result of using an accelerator. 

Hydrated lime will keep for a very long time but you must make sure that you keep it absolutely dry. If you store it in a plastic bag that is tightly sealed a large bag of hydrated lime will last for years. If you don’t make the effort to keep it dry it will draw moisture from the atmosphere and after a while will start to solidify. If it does start to harden it will become almost as hard as concrete and will therefore be unusable. So it pays to take care of it.

Using an accelerator with added hydrated lime may appear to be an unnecessary complication but it is well worth doing because if space is tight and you haven’t got much room for a large composting project you need to be able to speed up the process.

As for the quantities of accelerator and hydrated lime, the best thing you can do is to use trial and error if you think you aren’t using enough accelerator then add more and the same applies for the hydrated lime. After a while you will develop a feel for what is needed. If your compost looks right, smells right and feels right then you can assume that you’ve got it right.

Making compost indoors

Making compost indoors can be done. It’s a question of finding a suitable container that has been tried and tested and you know that it works. Some attempt to make their own container. This can be done with considerable success but you need to know what is required to make compost effectively.

If you get it wrong you may end up with a mess so if you’ve never done it before and you don’t know much about how to make compost then the best thing you can do is to buy a ready-made composting bin that is suitable for in the kitchen or on the balcony. 

Making cactus Compost

When making cactus compost we have to think about free drainage of water more than anything else. On the rare occasions when you actually water your cactus plant, the plant will absorb all the water it needs and any excess must drain completely away from the plants roots. If this doesn’t happen the plant will remain moist around the roots and this will attract fungi which will start to rot the plant.

The container that holds the cactus can be filled with layers starting with free draining pebbles in the base above which there can be a mix of mainly sand and some peat like material. This can be replaced with compost that you have generated from your own composting scheme but you mustn’t use too much because the mix has to be free draining enough for excess moisture to get away.

Vermicompost tea recipe

Making vermicompost tea is very easy but first we have to know that there is much conjecture about what type of vermicompost tea you need to make. Some say that you need to aim for either a bacterial tea or a fungal tea and there are all sorts of things you can do to tweak your tea to get the desired result. Each of these types of tea have their place.

For example brassicas apparently benefit from a tea that has a high level of bacteria compared to coniferous trees which appear to benefit from a high fungal level of vermicompost tea. Then there are fruit bearing plants which benefit from a balance of bacteria and fungi.

If you can achieve these levels of refinement then good for you but it all seems like a lot of effort when you consider that all plants will benefit from the nutrients that are found in vermicompost tea.

If we work on the premise that whatever tea we can extract from vermicompost will do what we want for our plants which is to feed and nourish, the process of extracting that tea need not be complicated.

To make vermicompost tea you just need to load some vermicompost into a filtration container. This could be something as simple as an old sock or some fabric material which will allow water to soak through. Essentially you need to create a bag of vermicompost which is tied off at the top to hold in the material just like a big tea bag.

Then just like making tea that you drink you soak the bag in a bucket of water and leave it soaking overnight or maybe a day or two. This will ensure that the water can get into the vermicompost in the bag and by a process of diffusion the nutrients in the vermicompost will drain out into the water.

When the water in the bucket appears to be coloured by the tea, you can take out the bag, just like any other tea bag, then throw the contents on the compost heap or put it in the compost bin. You then have the tea which you can play with and use it as one of nature’s most genuine organic fertilizers.

It’s probably best to use it as soon as possible because if you leave it hanging around too long the nutrients will become digested by the bacteria present denaturing the solution rendering it as lower value as a plant food.

Making compost tea is a wise move and will provide an instant natural speed-boost to any plant especially those which bear fruit for example tomato plants. The nutrients from compost tea will, most often, invigorate plants making them stronger and more healthy giving them a much better chance to fight off diseases.

There is a theory that when you allow compost tea to come into contact with the leaves of the plants which you want to feed, the bacteria in the tea will protect the plant from invading diseases.
Producing a good compost tea could be described as an art and it is something that you will get better at with practice. When you see the benefit of using compost tea on your favourite plants you will want to make a habit of it.

Can you put a compost bin on concrete?

Can you put a compost bin on concrete?

You can put a compost bin anywhere that’s convenient but out of the way. If the only space you have is covered with concrete, this needn’t be a problem. You need to be aware that there may be some liquids that will emerge as a result of the type of material that will be going into the compost bin.

Anything to do with making compost tends to be messy. Compost bins are where everything is supposed to rot down and when this happens, juices of a dark nature will often appear. A compost bin that’s sitting on bare and clean concrete will display these dark juices. Especially so if the concrete is of a pale colour as concrete often is.

The juices from a compost bin are likely to leave a permanent stain on the concrete. This is a good reason for doing everything you can to prevent any juices from reaching the concrete.

The amount of liquid that’s likely to emerge from a compost bin on concrete is unlikely to be very much but it would be enough to leave a stain. There are a number of ways of managing a compost bin on concrete that will eliminate the risk of leaving any permanent stains. The aim has to be to absorb as much liquid, if not all of it, inside the base of the compost bin or to contain any liquid that manages to escape.

When you have decided where you want to place your compost bin on your concrete area, you need to put down a sheet of plastic that will extend to about 18 inches beyond the base of the compost bin. The edge of the plastic needs to be held up by some means. A line of bricks or small stones, will suffice to hold up the plastic around the edges. 

This will contain any liquid that comes out at the base of the compost bin. A layer of sawdust or fine wood-shavings would soak up these juices and keep them out of sight.

With a plastic membrane in place you will then be ready to start filling your compost bin with waste from the kitchen. Before you start you need to place a layer of dry material in the base of the bin. 

For this, you could use shredded newspaper or cardboard. A better option would be to, again, use dry sawdust or, if you can get it, dry earth, preferably dust. You need a layer of about 6 inches. This will absorb most, if not all, of the moisture that your composting campaign is likely to generate.

If you have enough absorbent material in the base of your compost bin, it’s quite possible that you will never see any liquid come out onto the plastic membrane. Think of the membrane and layer of sawdust, as an insurance that will protect against the inevitable emerging dark liquids.

Another, more flamboyant, way of featuring a compost bin on a concrete area, could be to incorporate it as part of a raised bed where you can also grow plants. This would probably end up as a permanent feature in your concreted area but it can work well. 

This wouldn’t involve putting a compost bin on concrete directly but placing it in a raised position. The biggest advantage with this is that any dark liquids that emerge from the compost bin, will soak into the soil and be used by growing plants.

Having a bin placed on soil in this way would also allow for worms to find their way into the compost. It would be as good as having a compost bin in an open garden on bare soil ground.

Where else could a compost bin go?

Someone suggested putting a compost bin on tarmac. Some people seem to think that tarmac is porous and that the dark liquids that come out of a compost bin would soak away without trace.

This is not so. The surface of tarmac will be sealed. Nothing will be absorbed by tarmac. If you have an area of tarmac and you want to place a compost bin on it, you need to think of it in the same way as [concrete].

Placing a compost bin on patio paving slabs

You can manage a compost bin on a patio in a number of ways. You could treat the patio area in the same way as a concrete or tarmac area. This would involve having a raised area for the compost bin to sit on or provide a plastic-sheet catchment for the liquid that may emerge from the base of the bin.

Another option for a patio area is to lift a slab or a number of slabs to reveal the soil beneath the patio. Earth can then be imported into this area and the compost bin can be placed on top of this. Any liquids can then drain into the ground under the bin. It is possible for a compost bin on the patio, to look like an organised feature.

Putting a compost bin on wooden decking

It wouldn’t make any sense to place a compost bin directly on a wooden deck. It is possible to manage a compost bin on any wooden base but you need to contain the liquids that will inevitably emerge. 

One consideration must be the strength of the wooden decking construction. The compost bin is likely to become heavy as you fill it. So, it may be necessary to strengthen the construction of the decking but this may only be necessary directly under the place where the compost bin will go.

Then, you will probably need to build some sort of containment similar to placing a bin on concrete but being on wooden decking, it could be made from wood. This could then be lined with plastic sheeting and filled with soil. Any liquid that turns up from the bin can soak into the soil and you could grow small plants around it.

Putting a compost bin on gravel

Placing a compost bin on gravel should work as well as putting it on bare ground. Provided there is sufficient drainage under the layer of gravel, there shouldn’t be a problem from any emerging liquids. If the layer of gravel is relatively shallow, it could be possible for worms to find their way in. It would help if you put a layer of soil in the bottom of the bin, just to help get the composting process started.

Placing a compost bin on bare-earth is the best place

This is for those that have a garden and plenty of space. Bare earth in an open garden is the ideal place for a compost bin. You wouldn’t need to worry about any liquid draining away. It will, simply, disappear into the ground. There will also be the added advantage of worms, in the soil under the compost bin, having immediate access to the compost that’s forming in your bin.

Where you have a compost bin that’s away from bare ground or not open to soil generally, you may feel the need to add worms from an outside source. This will depend on how you feel about having worms in your compost bin. It is possible for compost to form without any worms involved at all but remember that worms will help to process food waste much faster in any compost bin or tumbler.

Could a Rolypig composter work on a balcony?

Balcony compost with the Rolypig

The answer to this has to be no! Unless you have a large balcony which is unlikely. The thing is with the Rolypig, you need some room to be able to roll it around. It isn’t often that you have to roll it but when you do there has to be enough space. The ideal place for the Rolypig is on a lawn area outside in the open. It’s not suited to being used indoors at all.

Balcony compost Rolypig tail

Apart from needing some manoeuvring space there is the issue of the occasional liquid coming out. This is no problem on a lawn because it will feed the grass but you wouldn’t want it indoors on the floor. Find out more about the Rolypig composter at

Balcony compost from the Rolypig

To sum up:

Balcony compost

  • A wormery may be your best option on a balcony
  • Consider a bokashi bucket system
  • A small compost tumbler will work on a balcony but you will need to collect the liquids
  • The Rolypig composter isn’t an option for a balcony


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 Can you put cooked meat in compost? Bokashi soil factory Compost flies

 Find out about 'Brown' material in compost. What to put in compost bin to start.  Can you use compost for growing vegetables?

 Grow potatoes in a bin. Composting tea bags. Hot composting in winter. 

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