earthworm stampthe plough is one of man’s most ancient and valuable inventions,  but long before he existed, the land was in fact regularly aerated and ploughed, and still continues to be, by earthworms – Darwin

There are about 800 earthworm species on earth and they are found almost everywhere, except in extremely cold areas. In South Africa there are about 200 earthworm species of which 6 contribute to ‘ploughing’ our garden soil.


The silent heroes of your garden.

  • Earthworms are referred to as ‘the intestines of the soil’ as they literally eat their way through soil. An earthworm consumes it’s own weight in soil daily – that’s about 9kg/m2 a year.
  • Soil and organic matter mix with bacteria, fungi and other soil organisms in the earthworm’s digestive system.
  • Earthworms’ castings contain nutrients in a soluble combination which is easily absorbed by roots of plants.
  • Castings are 6 times richer in nitrogen, 10 times richer in potassium, 7 times richer in phosphates, 3 times richer in magnesium, 2 times richer in calcium than the original soil.
  • Earthworms secrete calcium carbonate which improves the pH of the soil.
  • Plants use earthworm tunnels to expand their root systems.
  • Earthworm tunnels are lined with rich castings to stabilize them and this is a great nutrient source for roots.
  • Earthworms encourage beneficial soil micro organism to grow – they increase soil porosity, allowing oxygen and water into the soil.
  • Earthworms discourage disease causing organisms like bacteria and nematodes in soil.

Protecting Earthworms in your garden.

Earthworms are very sensitive to salts. Avoid synthetic fertilizers as these are salt-based and in their concentrated form they kill our silent heroes as well as many other soil organisms. Continued use of synthetic fertilizer turns the soil salty or acidic and will discourage earthworms.

Frequent tilling and spraying of pesticides will also kill or discourage earthworms and soil organisms and you will lose all natural fertility in your soil.

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Mulch is a must in organic gardening.

Mulch helps to maintain and promote soil fertility and is incredibly important in your garden, whether it be a simple vegetable bed, amongst flowers, annuals, perennials or under trees.

Mulch benefits to the soil.

  • Breaks down to add nutrients and organic matter to the soil
  • Provides a good environment for earthworms
  • Provides nutrients for soil micro-organisms
  • Promotes soil water retention
  • Reduces leaching of soil nutrients
  • Suppresses weed growth
  • Forms a blanket on the soil to promote a constant temperature so soil micro-organisms can flourish

Mulch benefits to gardeners.

  • Makes tiling of the soil easier – mulch encourages soft and friable soil
  • Reduces weeding – mulch covers areas to suppress weed growth
  • Reduces watering – mulch conserves moisture
  • Reduces the need for fertiliser – mulch encourages soil-organisms to produce nutrients
  • Keeps low growing plants clean – mulch prevents mud splashing on plants

How and when to apply mulch.

bark mulchMulch can be applied all year round and is very important for establishing new gardens.

Spring – When preparing to plant for Spring, cover the entire bed in mulch. Leave a planting hole or opening for  seeds or seedlings and cover the rest of the bed in mulch. In colder regions allow the sun to warm up the exposed soil for 2-3 hours before planting.

Summer – Keep your soil covered in mulch throughout the season. In hot, humid areas mulch breaks down more quickly and should be replenished more often.

Autumn – Empty your garden beds for winter planting and leave the ground bare for a few days to give the birds time to feed on insects and grubs, then mulch entirely.

Winter – Keep the beds covered in a thick layer of mulch to conserve warmth in the soil.

Starting a new garden – Set out the garden beds, weed the area, add rock-phosphate or bone-meal, water and then completely cover the area with mulch. Use up to 10cm thick mulch layer on sandy soil and no more than 5cm thick on clay soil. You can plant at any time after you’ve mulched. Add layers of mulch when it is absorbed into the soil.

Under trees – Always leave a hand’s length between the stem of a tree and the mulch – this allows ventilation and prevents fungal disease from developing against the stem of the tree.

Mulch helps to keep your garden water-wise.

mulch bedMulch prolongs soil moisture – a blanket of mulch will shade the ground from the hot sun reducing evaporation. It also helps reduce the impact of heavy rain and allows the water to filter gently into the ground. Compacted, bare soil does not absorb water easily and applying mulch prevents soil compaction and erosion. Adding mulch to your garden beds is a simple and easy step in moving towards a water-wise garden.