Doing What Comes Naturally: Improving your Soil with Compost

The state of the soil in your garden was probably not high on your list of priorities when you were choosing a place to live.

If your house is on a new estate you are likely to find that the top layer of soil has been bulldozed away. Even when a layer of topsoil has been laid, your lawn may not mind, but the root systems of larger plants will inevitably struggle in the lower layer of lifeless soil.

Soil types range from sandy to clay, with a myriad of variants in between.

Sandy soil is made up of large irregular particles that permit water to enter between them and through so quickly that it dries out rapidly.

The particles in clay soils are very fine and become sticky when wet, and set hard when dry. This soil type tends to compact, which interferes with the oxygen supply to plant roots.

A good loamy soil has sand and clay particles bound together with humus to form crumbs, providing pore spaces for water and air. This soil structure ensures good drainage and adequate aeration.

Adding organic matter (compost) to either clay or sandy soils allows for easier root penetration and increases water-holding capacity. Worms and micro-organisms are an essential part of soil life, and they need plenty of organic matter on which to feed.

Plants also need mineral nutrients obtained from granite or rock dust. Soil microbes decompose the rock particles into the required minerals which can be used by the plant as required.

A slow release fertilizer made from powdered granite, basalt, rock phosphate and bentonite is available. This type of fertilizer need only be applied once a year as it will not dissolve in water.

Almost all organic gardeners have their own special compost recipe. Once you have the simple basic plan you can be as creative as you like.
• Select a site in your garden that’s at least 1metre long by 1metre wide, or use a container if you’re a bit on the neat side.
• Spread a 15cm layer of carbon -rich materials such as leaves, straw, dead flowers, wood chips and shredded newspaper.
• Add a 5cm layer of nitrogen-rich materials such as grass clippings, vegetable peelings, fruit rinds and barnyard animal manure.
• On top, place a 2cm layer of garden soil.
• Continue to build until the heap layers are about 1metre high.
• Keep moist (not wet) as this will speed breakdown of plant material.
• Turn with a garden fork every couple of weeks.

A couple of optional additions:
• Sprinkle on about 2½ cups of lime or dolomite and 1½ cups of rock phosphate.
• Add three or four chopped leaves of yarrow and comfrey to speed production and decay.
• Earthworms will quickly move in to add their valuable castings.

It’s a good idea to cover the compost heap during very wet weather. Excess water makes it smelly and heavy. The compost should be ready to use in 4 – 5 months in cooler areas, 10 – 12 weeks in warmer places. When ready to use, the compost should be black, crumbly, sweet-smelling soil.

Throw compost on top of garden beds or loosely fork it into the soil, then soak and mulch. Leave for a fortnight before planting seedlings.