Soil Types

It is essential to know what kind of soil you have in your garden before you attempt to plant anything as this knowledge will allow you to choose plants that are suited to your soil conditions. This is much more advisable than trying to change the soil conditions to suit the plants you purchase.

  • Soil Type: To ascertain what kind of soil you have you will need to dig several holes in various spots around the garden. This will give you an idea of the soil profile and whether it varies from place to place. Typical garden soils will have a thin layer of top soil which has a higher content of organic matter) over subsoil. The subsoil may consist predominantly of clay, sand, rock or stone and will not contain much organic matter. However all types of soil can support a healthy garden but remember to plant according to your soil type otherwise plants may die and you will have wasted precious time and money.
  • Drainage: To check how well your soil drains, fill the holes and time how long it takes for them to empty. If the water drains very quickly then you probably have sandy subsoil and it will be important to use mulch and water-storing agents to retain moisture. If the water remains in the holes after a few hours you probably have clay subsoil. You can choose to use raised beds and use organic matter for added drainage. This will also encourage earthworms which will help to aerate the soil. The best option is to choose plants that thrive in your soil conditions.
  • Soil improvement: The best way to improve any type of soil is to add lots of organic matter; dig the soil over and mix mulch into the subsoil. The mulch will break down and add nutrients to the soil for your plants to utilise. A great idea is to use leaf mould from your garden; rake up your autumn leaves, put them through a mulcher, compost the leaves and add to your garden soil once they have been converted to a nutrient rich leaf mould.
  • Checking pH: It is relatively easy to check your soil pH. Purchase a pH testing kit and follow the instructions. If your soil is acidic (6 or below) it will be suited to plants like azaleas, camellias, gardenias, ericas and rhododendrons. Many Australian plants will thrive in soils with a pH of 4-6. If your soil is fairly neutral (6.5 to 7.5) most plants will grow. If your soil is alkaline (8 or above) it will be suited to plants like ceanothus, irises, lobelia, lilac and sabina. You can alter the pH by adding lime to soil that is too acidic and sulphur to soil that is too alkaline. However, it is better to choose plants that suit your soil pH rather than attempting to change it.