Composting: Why bother? (and a quick "how to" guide)

We use a lot of compost in October. Every courgette, tomato, capsicum, and eggplant that we plant gets a good shovelful or two in its hole, as well as a handful of fertiliser. If we had to buy all the compost we use, I conservatively estimate it would cost us about $60 a year (producing three 200L bins per annum at $0.10 per L).

The other way to look at it, is that combined our kitchen scraps and our garden waste makes $1.15 worth of compost each week. I like that even before doing these sums, I have come to look at our food waste as a resource! And of course we are dealing with our own waste, rather than transporting it somewhere else to a landfill.

So how do I compost? Well, quite differently from most people I suspect. For starters I am a bit "over the top" when it comes to composting - we have three large compost bins in the garden. But this does make the job of making compost easier, as well as boosting the volume. I fill the three bins sequentially, and when all three are full, the oldest is ready to go on the garden. This is usually when the material in the bin is 6-12 months old, depending on the time of year (compost rots a lot faster during the warmer months).

To make compost 'the easy way" here are my instructions:
  1.  Site the compost bin so that it gets as much sunshine as you can. The more the merrier, but make sure it gets at least a few hours of sunshine each day. Sit the base so its nice and level, stable, and in direct contact with the ground.
  2. The first layer needs to be coarse, small woody material (garden prunings, sticks, leaves, weeds), Pile this at least 20-30 cm deep in the bottom of the bin. This ensures there is adequate oxygen getting into the heap, which speeds rotting and reduces odour. My compost heaps DONT smell.
  3. Then pile in everything you can compost, but alternate so you get layers of different types of materials. I find good things to compost include: garden prunings (branches up to 1 cm diameter, all cooked or raw food scraps (uneaten leftovers, vegetable scraps), cardboard, paper, used tissues, eggshells, hair (if you get yours cut at home), coffee grinds, weeds (except for wandering jew (Tradescantia fluminensis), oxalis, or anything with long lived tubers or seeds), lawn clippings, and old potting mix. 
  4. Meat scraps, raw or cooked, can be added as long as you cover them at the same time with a good layer of other material, so that you dont breed flies. For most people this is a big NO, but it doesn't actually cause any problems. What I don't do is compost chicken bones or carcasses - the bones break into sharp fragments that later have a tendency to skewer fingers in a rather unhygenic way!. 
  5. Larger garden prunings are OK throughout the heap, following the "if it can rot it can be compost" mentality. It just means that the bits that havent completely rotted yet when you empty the heap get put back in the bottom of the next heap.
  6. Alternating layers is the trick to "anything goes" composting. It makes sure the compost heap isn't too dry, or too wet, or lacking in oxygen, and it helps build a strong worm population. You can be assured your compost heap is working well if its nice and warm when you lift the lid, even if its a cool day.
  7. Keep filling the bin till its full, then leave until its a fine textured, crumbly, dark brown to black humus that is perfect for the garden (6-12 months). If you only have room for one bin, when you get to the top of the bin you will need to put the bottom half of the bin on your vegetable patch, and then put the top half of the compost back into the bin. Its a lot less effort to have multiple bins, and wait until the whole bin is "garden ready". 
If you want instructions on the more standard way to make compost, the following link is a useful website. The principles are the same - alternating layers and sunshine.

composting Wairarapa

Whats growing
Our garden is now almost full and ready for summer. We currently have the following growing:
Tomatoes (9 varieties), eggplants, capsicum, strawberries, raspberries, boysenberries, spring onion, calendula, mizuna, courgette, pak choi, garlic, coriander, lettuces, mesclun, beetroot, radishes, cucumber, basil, beans (Purple King, Dalmation, Scarlet Runner), rhubarb, grape, peaches, apples, rosemary, oregano, parsley, sage, bay, mairehau, thyme, chives, silverbeet.

Tomato planting tip:  When planting, or after planting if you have already got yours in the ground, bury the bottom few centimetres of the stem too. The plant will produce extra roots from the bottom of the stem, giving the plant a growth boost. If you look closely at the bottom of the stem, you will probably see little white nodules - these are roots that are trying to grow above the ground.

Cost/benefit analysis
Benefit minus costs is a bit lower this month - we have done a lot less cooking than usual, and have had some higher costs such as purchase of pea straw, lime, and ZooDoo compost (a compost with animal manure, that we have used for our tomatoes).  Savings year to date (August-October): $83.20, and a summary for the month of October is below.

Happy composting,


kg/quantity price value
oranges 0.6 3.97 2.38
oregano 1 packet 3.25 3.25
lettuce/mesclun 5 bags 3.68 18.4
bay leaves 1 packet 3.68 3.68
parsley 1 packet 2.99 2.99
rosemary 1 packet 3.25 3.25
thyme 1 packet 3.25 3.25
spring onion 1 bunch 2.29 2.29
lemons 1 kg 3.95 3.95
garlic 1 bulb 1.32 1.32
silverbeet 1 bunch 3.75 3.75
alfalfa sprouts 1 packet 2.25  $          2.25



alfalfa seeds (c.300 g)

ZooDoo compost 40L

pea straw 50L

garden lime

mint plant

chives plant


 $        32.37
time spent for October: 2 hours

benefit minus costs

 $        18.39