You usually see Calum sorting out the PA systems and sound for SVM but in June he got down and dirty at Activism School and shared his knowledge and love of composting!

Below is his talk!

Often you will hear a lot of rules for composting; no citrus, no onion, get your ratios rights, turn regularly. If you’re looking to build compost or dispose of your food waste, it can all seem a bit intimidating. But, an understanding of some simple basics can make composting seem much more accessible.

As you start to think about how to make a compost system work for you, you can find something that suits you. Do you need lots of compost to keep a garden healthy or do you just want to reduce your food waste? What level of physical work are you willing or able to do? How much space or time do you have?

Don’t be too strict with the rules, try to find something that suits your needs and don’t shy away from making mistakes. The worst that will happen is a few bad smells.

What to put in?

The microbes that will help to break down your waste need four things to get going; Carbon, Nitrogen, Water and Oxygen.

Carbon and Nitrogen are just describing our waste organic matter, this is all the dead plants that will break down into nice compost. Generally, most of the organic waste you will have won’t be very high in nitrogen but that’s okay because you want a large volume of carbon.

A good guideline to getting a good mix is to have equals parts ‘green’ to ‘brown’ organic waste.

High carbon waste is brown and dry. Things like wood chips, dried leaves, cardboard or hay are all high in carbon. Whereas high nitrogen materials are generally green and wet; grass clippings, fresh garden waste or food scraps. Then there are some super high in nitrogen material, like coffee grounds or animal manure.

An important note here; don’t get confused by the word ‘green’; some very high nitrogen materials are actually brown like coffee or manure.

Water is important because all those microbes need something to drink. You want your pile to be as wet as a wrung-out sponge and the best way to test that is to pick up some of the compost and give it a squeeze, only a few drops of water should come out. If it’s too wet add some brown, carbon-y material, if it’s too dry add some water.

Introducing oxygen is very important to keeping you compost pile smelling nice. We want to promote aerobic decomposition, which is performed by oxygen-loving microbes. Low oxygen environments will promote anaerobic decomposition, and this is what leads to an awful smelling compost.

This is why turning a compost is important, it is how we introduce oxygen. The best way to turn a compost pile is to just shovel it from one place to another. But this can be labour intensive and if you’re not keen for that there are some other options:

Compost screws: these are large handles with a screw that you can dig into the pile to shake it up a little.
Tumblers: Bins that are on an axis, you can just spin them round to give the pile a turn.
Introduce Space: Placing large size items in your pile, big sticks or ferns for example, can help to create space within the pile.
Cold composting: If you just keep your compost less active, it will consume less oxygen and need less turning.

How often should you turn? It depends on how active your pile is. If it is hot to the touch (just stick your hands in!) it needs a turn. Colder, less active piles won’t need to be turned so regularly.

Hot vs Cold Composting

Tweaking the ratios of these four basic components will lead to different rates of decomposition and this is how we can really tailor a pile to suit our needs.

Adding high amounts of nitrogen and keeping your pile very wet will lead to a very active decomposition which will generate a lot of heat. A ‘hot compost’ like this is great if you want to make a lot of compost quickly to feed a garden but it also requires more work as it needs to be turned regularly. They also need to be large enough to be able to retain that heat, which often requires them to be built all at once, meaning you need a lot of material at hand.

Cold piles are less active and can take longer to break down, up to 12 months. They are generally kept drier, are low in nitrogen and, because they are less active, will consume less oxygen, requiring less turning. Piles like these suits someone who has a smaller amount of garden waste but it still looking for somewhere to put their food scraps. It is something that you can build gradually and turn less regularly. A tumbler style container would suit this system well.

Neither is better, find something that suits you! A hot compost pile will generate a lot of nutrients for your garden but building one will commit you to a lot of turning for the next month or two (or a lot of bad smells if you neglect it). A cold compost pile wont yield very much compost but will tolerate a more hands-off approach.

Potential Problems

Bad smells are the main problem that you will hear about when it comes to composting. This means your pile has gone anerobic, you need to add oxygen by giving it a turn. Drying it out will help too, so add some dry, carbon material.

Rodents are another problem to consider, especially in winter when there is less food and the little guys are hungry. My favourite solution it to just make peace with the rats and get on with life but your roommates might not like you for it, so we had better do something.

The best solution is to add some nitrogen material and water, once the pile gets really active the rats won’t be interested anymore. You can also try to create barriers to keep them out. Placing your pile on top of some chicken wire will prevent them from digging under but still allow all the worms to get in. Finally, there are many containers that are completely enclosed, like the compost tumblers, that rodents won’t be able to enter.

It’s also worth considering the potential of spreading weeds through a compost system. If you let your lawn go to seed and then add the lawn clippings to your compost, all those seeds will end up in your vege patch and make your like hard (true story…). There are also many nasty perennial weeds with invasive roots that will spread if they are added in your compost. To avoid this its best to do your weeding before everything goes to seed and try to identify those perennial weeds to keep them out of your compost.

But really, in the grand scheme of things none of these problems are a big deal. I have experienced them all and I will experience them again. Life goes on!

Small Scale options

A compost system like this isn’t for everyone. You really need a good supply of garden waste to keep it going. Not everyone has access to this. But there are some good options for smaller scale systems

Worm farms; if all you want to do is break down food scraps but don’t have much garden waste, this is a great option. Just remember worms need bedding, these are brown materials that provide a medium for them to exist in and it makes up 50% of their food, so don’t neglect the bedding! You can typically find layered systems, but these do require lifting the heavy trays when they’re finished. A flow through worm bin is a nice option that requires less heavy lifting.

Bokashi bin; this is a bin of fermenting organic matter. You are mixing your food waste with a microbial culture that is generally a liquid or inoculated grain. These are great because they can accept anything and take up little space. But it is important to have somewhere for the waste to go when its finished. You can bury it in the garden or add it to a compost or worm bin. Just have a plan of what to do with it before you get started.

Community solutions; there are many great groups out there who can help you to get involved. Find your local community garden or a friend who is into gardening is a great start. They will always have a compost pile and will generally be happy to take more scraps. However, it is important to respect the work that goes into managing these community compost systems. Please don’t treat them like a bin to dump your scraps, get involved and engage with what the community is doing!

Finally, there are many initiatives run by local councils to get people involved. You will have to find out what happening in your own area, but the Inner West Council has a few good initiatives to get you started. Compost Revolution provides heavily discounted composting equipment for people in the Inner West. The Compost Collective provides equipment and training for people in the Inner West to help set up their compost systems

All that aside, the best advice I can give is to just go and do it. It really is easy to do and even if you don’t get it right the first time, the stakes are really low. Don’t stress, just throw some leaves on the ground and you’ve made your first compost pile!