Down to Earth – Episode 3: making compost (1990)
“Down to Earth” was a series of thirteen segments shown on the ABC’s “Gardening Australia” programme. In each episode, Kevin Handreck from CSIRO’s Division of Soils offers information and advice on soil and gardening for the home gardener.
This episode gives a few simple tips that will make all the difference in producing good compost.
The fully revised edition of Kevin Handreck’s classic best-seller contains a wealth of information for practical gardeners.
[Music plays and title appears: Gardening Australia 3 Making Compost]
[Image changes to Kevin pushing a wheelbarrow full of composting materials]
Kevin Handreck: Have you ever thought of making compost? It’s really very simple. There are several ways that you can do it but the principles are the same for all of them. This is a rather large heap in the Adelaide Hills on a farmer’s place and you can see that the heap here has been made from various animal manures. There’s horse droppings and whatnot there, there’s straw and sawdust and bits of chicken litter and so on.
[Camera zooms in on the compost as it’s turned over with a pitchfork and steam is released]
It looks a pretty rich mixture. Let’s see how it’s working. Wow, look at all that steam there. It’s really going very well. The reason why this heap is working so well is it has just the right balance of materials and the right moisture content.
Now your heap probably won’t be as big as this in your back garden and you may not have the same sort of materials but I’m going to show you how it’s possible for you to be just as successful as this. You need high nitrogen materials and some low nitrogen materials.
[Camera zooms in on the contents of the wheelbarrow as Kevin shows an example of each item he is describing]
High nitrogen materials are weeds from the garden, various scraps and all these green sort of things, things from the kitchen, animal manures particularly poultry manure. They’re all high nitrogen materials and the low nitrogen materials can be sawdust, straw, leaves from out in the street anywhere, twigs that come with them. The balance that you need is something like three or four parts of these high nitrogen materials to about one part of these low nitrogen materials. Let’s add them to the heap.
[Kevin empties the contents of the wheelbarrow into the compost and mixes them through whilst adding some water from a hose to the pile]
The materials have to be mixed together fairly thoroughly and they also have to be of just the right moisture content. These are a bit dry still so we’ll add some water to them. The thing is that the bugs, the bacteria and fungi that are going to be doing the composting for us are just like us. They need oxygen and they need water and we have to get the right balance in this heap. Let’s see. The way to check for moisture content is with the squeeze test.
[Kevin picks up a clump of compost and squeezes it, drips of water come out]
I’m squeezing the mix now and you can see water coming out of there. That’s just right so this heap’s ready to go. It’s got the right balance between high and low nitrogen materials and the right balance between oxygen and water.
Now if you’re in a hurry to get compost then what you need to do is to turn this heap every few days adding water, making sure that the oxygen concentration is high enough in there for the bugs to really keep working and in three weeks you should have reasonably mature compost. Now if you’re not in a hurry the best thing to do is just to leave all these materials in the heap for about three months and at the end of that time you’ll have something that’s like this. Beautiful, isn’t it?
[Kevin picks up a small bucket with mature compost in it; the camera zooms in on the sample in his hand]
[Image changes to show suburban street with city skyline in background]
Even if you live in the inner city you can still do your bit in recycling organic matter.
[Image changes to show Kevin holding a plastic tub with composting material in it]
If you think you need a lot of space to make compost think again. Let me show you down here. The ideal solution to making compost in a small yard like this is a compost bin. It’s really very easy to manage a bin like this.
[Kevin walks down a path to a green compost bin. He removes the lid and empties the contents of the plastic tub into it] All you need to do is to sit it on the ground and then start putting in anything that you might have used in a big compost heap, kitchen rubbish, old flowers, weeds from the garden. Just make sure that the mixture is moist enough so you can put a sprinkle of water on from time to time and if you’re using a lot of orange peels or other citrus peelings that are very acid it’s worthwhile just putting a sprinkling of lime over the top of the mix every now and again in there. After a few months you’re going to have something nice. Let’s have a look and see what we’ve got down here now. Wow look, isn’t that terrific? Look at it. Magnificent and that was rubbish only a short time ago.
[Kevin lifts the bottom of the compost bin up to reveal the mature compost]
You can use your compost almost anywhere in the garden. You can put it under the mulch around your plants like so. Put the mulch back if you want to or you can just sprinkle it all round on the garden here, a good generous helping.
[Kevin sprinkles a bucket of soil around some plants in the garden]
The rain will soon wash the nutrients down into the soil to the plant roots. In the vegetable patch or where you want to grow bedding plants it’s probably best to dig the compost into the ground before you plant. Probably the only exception to that is where you’re growing carrots because if you have a lot of rich compost in the soil under carrots the roots can fork and get other sorts of distortions.
Another use for compost is as a top dressing on pot plants.
[Kevin adds a sprinkle of soil to a fern in a hanging basket]
You can just put it around like that. Not too much otherwise you may reduce the drainage of water down through the pot. These plants will soon be thriving on the compost we’ve given them. Can you think of a better use for your rubbish? I can’t.