COMPOST IS BLACK GOLD
Successful gardens rely on well-nourished soil, and compost or a worm farm can help you on your way
Every good gardener knows the premise “Feed the soil, not the plant”. We all know that soil is the most important component of the garden, and that a major part of our budget should be spent on looking after and replenishing it. Compost — which many confidently call black gold — is essential to rich soil, and it’s ours for the making.
Two words hold the key to success with compost: air and heat. You want aerobic composting, the result of capturing air and heat: your compost bin needs to generate heat that reaches 55C.
If you have the space, a three-bale bin is best. This is usually constructed of hardwood, with front sections that can be removed for ease of access and handling, as you can see in this picture of Walter McVitty in his beautiful garden on Victoria’s Mornington Peninsula.
This also allows the essential step of turning the composting material with a large fork.
One bin is a work in progress into which you add, each day, kitchen scraps: eggshells, paper towels, ripped-up egg cartons and garden prunings. Don’t add meat, dairy products and fats, which can encourage ro- dents. Grass clippings, leaves, old vegetables, coffee grounds and tea leaves, floor sweepings, vacuum cleaner contents and wood ash can be added.
Build up each bin, with numerous layers of vegetable matter, then layers of poultry, horse or cow manure, interspersed with layers of soil.
Once this is full, leave it to heat and “cook”, undisturbed, for a few weeks. This is then turned, daily if possible, with a fork until the material is completely broken down and dark, crumbly, sweet-smelling compost has been produced.
Meanwhile, the second bin is filled and left untouched, happily heating. The third bin contains the finished product.
With this three-bale method, perfect compost can be produced each month in summer and every two months in colder weather. There is always one bin finished, ready to be shovelled on to the garden as a thick mulch and fertiliser.
A range of enclosed composting contraptions for those who garden on small city plots is available: one of the most successful is the style involving a large heavyduty plastic wheel, which is easy to turn.
Remember, compost piles need carbon (derived from woody carbohydrates) and nitrogen, which comes from lawn clippings and kitchen waste, in the correct ratio. This is known as the C:N ratio.
One kilogram of urea per cubic metre will improve the nitrogen level in the heap, as will comfrey leaves, poultry manure, blood and nettles.
It’s not always possible, however, to erect a compost bin: impossible, surely, if you live in an apartment.
The worm farm may be the answer to the small garden owner’s wish to ensure that food scraps don’t go to waste. There are several brands available, including the Can o Worms and the Worm Cafe, which are both easy to assemble.
You buy a starter kit of at least 1000 worms when you purchase your worm farm, which is available from most good-sized nurseries. Some packs of worms are supplied with bedding, which the worms will eat before climbing up, into the top tier — known as the working tray — to demolish the food scraps.
Don’t be too hasty in the first few months to fill the working layer with food. Too much food, supplied too quickly, will rot, encouraging the tiny vinegar fly, which
Two words hold the key to success with compost: air and heat
is attracted to anaerobic and acid conditions, which will make your unit smell. (Vinegar flies are annoying, rather than unclean, however.)
You should see worms eating and converting the food before adding more scraps. This can be slow during the early months until the worms multiply, after becoming accustomed to their new environment, and until they demolish the original bedding.
You can balance the environment to assist the entire process by tipping a handful of garden lime — dissolved in water as undiluted lime would burn the worms — over the working tray, after ensuring that the tap is open so that you don’t drown your worms. Keep the tap open, also, if it is raining, with a jug or bucket under the tap.
You can then pour the “worm tea” on to your garden or add it to your watering can to give your plants a beneficial foliar drenching.
Each time you add food waste to the working layer add a handful of soil to provide grit and traction for the worms. If you are fastidious, you may chop the food waste finely to assist the worms’ digestion and to speed up the production of the worm castings.
Make sure your working tray has a layer of newspaper, hessian or an old towel completely covering the food waste to ensure a dark, moist environment, which will encourage the worms to move up into the food layer.
Just about anything can go in: avoid, however, onion, citrus peel and, of course, meat products.
Now is the time to mulch your garden, and you can do no better than use Sarah Curry’s Majors Mulch, clever little pellets of compressed lucerne that expand when wet.
If you have a massive garden you can contact your local farm co-operative to ask about bales of lucerne that have been spoiled by rain.
(At a former 3ha garden in the NSW southern highlands I used 1200 bales each year: once it broke down into the heavy clay the soil was a rich, red loam.) Holly Kerr Forsyth attained a PhD in 19th and 20thcentury gardens. Follow her on Twitter: @hollykerforsyth.
Clockwise from above, Walter McVitty turning compost in his garden on Victoria’s Mornington Peninsula; Sarah Curry’s Majors Mulch; bales of lucerne