The secrets to perfect compost


Gardeners dream of making the perfect compost to feed their precious plants and make them thrive. So how does one get earthy, rich, black gold instead of a smelly rotten mess? Here are our secrets to perfect compost.

Choose the Right Container

There are a variety of containers on the market or you can make your own, but a heap placed directly onto the soil is just as good. A box constructed of timber should have air holes between the timber slats to ensure aeration and should not be a higher than 1.5m.

Two boxes is ideal – as one matures the other is being filled. Bricks or clay pipes at the base will help with air circulation. These must be spaced about 10cm apart and covered with woody plant stems or small twigs. Do not place on concrete as the soil base helps with aeration and drainage.

Know your Browns and Greens

Greens are fresh green matter such as grass clippings, vegetable waste or fresh leaves, which are nitrogen rich. Browns are fallen leaves, straw, sawdust, shredded newspaper and the like, and contain high proportions of carbon.  The ratio for good compost is two parts browns to one part greens.

Up to 10% of the material can be rough material like small sticks and prunings, which help with aeration and prevent material from packing down and clogging up.

It’s all in the Mix

Mix all the greens together and chop up anything too big. Place a layer of two buckets of browns and then add one bucket of greens. Repeat this process 2 – 3 times, then add a sprinkle of compost activator, ground limestone, wood ash or bonemeal and a handful of soil. Mix thoroughly.

Careful Watering

The perfect compost heap is moist but not soggy. Water a new pile with 1– 2 litres of water using a fine mist spray, and being careful not to over-water. It’s a common mistake to use too much water. Remember that ‘greens’ may not look wet but can contain up to 95% water. The overall moisture content should be 60 – 65% (as moist as a wrung-out sponge). It’s better for a compost heap to be a bit too dry than too wet – it will just take longer to mature.

Be Patient

Compost can be made in 6 – 8 weeks , or it can take a year or more. In general, the more effort the quicker the compost. When the material has turned a dark brown and has an earthy smell, the composting process is complete. It’s then best left for a month or two to mature.

Take note of the Do’s and Don’ts

  • Turn every 4 – 6 weeks.
  • Ensure that your heap is covered in wet weather.
  • Dry browns (fallen leaves, for example) can be kept indefinitely. Collect them in autumn and store them in plastic bags.
  • Evergreen trimmings and pine needles do not rot well and should be avoided.
  • Flies and unpleasant smells are an indication of incorrect making, usually too much water. Try adding more ‘dries’.
  • Shake as much soil off roots as possible before adding them to the compost.
  • Newspapers should be recycled to be made into more paper, but small amounts or paper towels can be used in compost.
  • Kitchen waste like fruit and vegetables, tea bags, coffee grounds and egg shells should be used, but avoid animal products and cooked food.
  • Don’t compost coal and coke ash, cat litter, dog faeces or glossy magazines.
  • A shredder can be very useful for woody material.
  • Diseased plants should be avoided.
  • Compost heaps are made by a host of small and microscopic creatures. These are not pests and will not overrun a garden.
The Gardener