For successful Autumn planting!

Good soil preparation is vital for producing strong and productive plants, masses of gorgeous blooms and tasty produce, but what exactly does soil preparation involve?

Follow our seven easy steps to successful soil preparation including tips along the way.


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Seven handy tips on how to prepare your soil for successful autumn planting

Key factors for creating a beautiful and productive garden!

There are two key factors for creating great soil for a beautiful and productive garden:

  1. Ensuring there is enough nutrients and moisture-holding capacity within the soil for plants to excel.
  2. Ensuring that plants can draw up the nutrients and moisture from the soil, to maintain a good quality of life.
Seven handy tips on how to prepare your soil for successful autumn planting

Step 1 – Dig over soil

  • Examine your soil a couple of weeks before planting to see what condition it is in and what has to be done to prepare it for new plantings or improve it for existing plantings.
  • Lightly dig over the soil to remove weeds, old roots and stones and to break up clods.
  • Be careful digging around existing plants as you do not want to disturb their root systems.
  • Keep an eye out for soil-borne pests such as curl grubs and remove them. Curl grubs are white, C-shaped grubs that are beetle larvae and feed on plant roots.
Seven handy tips on how to prepare your soil for successful autumn planting

Step 2 – Understanding your soil type and soil pH

  • If you are unsure of the pH of your soil, test a sample of it using a pH test kit following the instructions in the kit.
  • If you are unsure of your soil type (find your soil types below), or don’t have access to a pH kit, most garden centres can test your soil and give advice (a small cost may be charged).
  • If necessary, amend the soil pH to the optimum level for the plants you are growing. Most vegetables for example grow best with a soil pH of 6.5 to 7 (see ‘Understanding soil pH’ below).
  • Once the soil is amended, check your soil pH again to ensure it is ideal for the plants you are planting.
Improving soil over winter Seasol Liquid Compost

Step 3 – Garden beds with good soil

  • If you have been working with your soil before and you know it is fertile, easy to dig and holds nutrients and moisture well, it may need very little work before planting.
  • Check your soil pH to ensure it hasn’t altered since the last plantings or in case it needs to be modified for a different variety of plant. For example, soil under lawn that’s regularly fertilised can become increasingly acidic.
  • Remove weeds and spread a natural plant and soil conditioner such as Seasol Plant + Soil Booster through the topsoil. Water it well in after application.
  • If possible, leave your soil for a couple of weeks before planting to let beneficial organisms in the soil get to work.

Step 4 – Garden beds with poor soil

  • If the soil or potting mix is dry and hard to wet with water either pooling on the soil surface or running off, it is called hydrophobic which mean water repelling.
  • To create soil that absorbs water, treat it with a soil wetter such as Seasol Super Soil Wetter & Conditioner, following instructions on the container.
  •  Further improve the soil by digging in well-composted organic matter or well-rotted compost.
  • For a no-dig option, use a soil conditioner such as Seasol Liquid Compost. If possible, leave the soil to rest for a couple of weeks before planting to let beneficial organisms in the soil get to work.

Step 5 – Garden beds that can rest

  • If you are not planting for a while and have poor soils, plant a green manure crop.
  • Soils that are poor with little nutrition, low in organic matter, or have been cropped for many seasons can be improved with a green manure crop such as a legume, which adds nitrogen to the soil via nodes on its roots.
  • Green manure crops are grown from seed. After sowing, watering with Seasol helps with germination and aids plant establishment. Regular applications of Seasol (every 2-4weeks) will build strong and healthy plants.
  • Before the crop flowers, cut it down and dig it into the soil to increase nitrogen and organic levels in the soil. Leave to break down before planting.
Seven handy tips on how to prepare your soil for successful autumn planting

Step 6 – Raised garden beds

  • Raised beds are useful when the soil is very poor and hard to improve, if you have limited space within your garden or to avoid bending.
  • They are usually filled with bulk or bagged organic garden mix primarily made from composted bark. This mix slumps (drops in its level) as the mix breaks down and crops remove nutrients.
  • To replenish the mix, add compost, aged manure (or a manure blend), or a bagged vegetable mix. For a no-dig option, water in a soil conditioner such as Seasol Liquid Compost.
  • Dig the new materials through the old mix so it is well combined. If necessary, add a soil-wetting agent such as Seasol Super Soil Wetter & Conditioner to improve water penetration into the soil.
Seven handy tips on how to prepare your soil for successful autumn planting

Step 7 – Container or pots

  • Containers or pots are usually filled with potting mix. After a crop has grown, replace with new potting mix such as a Premium mix (indicated by a red panel with five ticks on the bag), which contains soil wetter and enough nutrients for the first couple of months of growth. Recycle the old potting mix into the garden or add it to the compost.
  • To refresh existing pot plants, soak the plant and pot in a bucket of Seasol for a couple of hours to revitalise the plant and potting mix.
  • If the water pools on top of the pot or runs down the side, then in may need a soil wetter such as Seasol Super Soil Wetter & Conditioner to improve water penetration into the soil.
Your Garden October 2020

Ongoing plant and soil care……

  • Once soil or potting mix has been prepared for planting, cover it with a thin layer of organic mulch such as sugar cane, pea straw or chopped lucerne.
  • Lightly hoe to remove any weeds that germinate.
  • Water the area well before sowing seeds or planting seedlings.
  • After planting, water with Seasol to help reduce transplant shock and reapply regularly (every 2 to 4 weeks) to promote healthy growth and strong root development.
  • Once plants have settled in, they need to be fed to ensure strong, vigorous growth and an abundance of gorgeous blooms and tasty produce. Apply PowerFeed All Purpose including Natives every 2 to 4 weeks during the growing season. PowerFeed is a dynamic fertiliser and soil conditioner.
Ensure water get into the soil - Seasol Super Soil Wetter & Conditioner

Soil wetting and soil conditioning products

Overly dry soils that are hard to wet may be hydrophobic, that is water repellent.

  • Apply a soil-wetter such as Seasol Super Soil Wetter & Conditioner.
  • For large areas, apply as a hose-on application. For smaller garden areas or containers, mix the concentrate with water in a watering can and water the solution over the soil surface.
  • Lifeless and nutrient-depleted soils can be improved by using an application of a soil conditioner product, such as Seasol Liquid Compost. It can also help to improve dry soil conditions.
  • At planting time to keep the soil and plants healthy throughout the growing seasons apply a natural plant and soil booster such as Seasol Plant + Soil Booster.

Soil Definitions Explained

When you are learning more about gardening and soil care you may come across terminology that you don’t understand. Here’s a quick guide to some of the concepts and terms relating to garden soil.

Soil consists of a mix of organic matter, compost, clay, sand or rock particles and is classified into the four categories of sandy soil, silty soil, clay soil and loamy soil (see below). Often soils in gardens are a mixture of several categories in different parts of the garden or at different depths. Soils at the surface (known as topsoil) may differ from those deeper down (subsoil). For example the top soil may be loamy but it may overlay a clay layer deeper down.

If you are unsure of your soil type, take samples from different areas and depths of your garden to a local garden centre for testing. They have local knowledge of your environment, soil types and pH.


Soil Types

Sandy Soil Easy to dig but one of the hardest soils to work with as it has low nutrients and poor water-holding capacity. It needs regular applications of organic matter and compost to retain moisture. Sandy soil feels dry and grainy.

Silty Soil Has good water and nutrient-holding capacity and is made up of fine particles of rock and other minerals. It’s generally a fertile soil that is good for plant growth and is sometimes used to improve other soil types.

Clay Soil Has the small tightly soil particles. It retains moisture well but may lack good air spaces. It can also crack when dry and is often hard to dig. Gypsum, organic matter and compost are added to clay soil to open it up so water, nutrients and plant roots can penetrate a clay soil.

Loamy Soil This is the gold class of soils with a combination of the beneficial properties of sand, silt and clay soils. It is easy to dig and retains moisture and nutrients making it ideal for plant growth.

If you are unsure of your soil type, take samples from different areas and depths of your garden to a local garden centre for testing. They have local knowledge of your environment, soil types and pH.

Understanding soil pH

Soil pH is measured on a scale from 0 to 14 with 7 neutral. Measurements below 7 are increasingly acidic and those above are increasingly alkaline. The ideal pH for soils for most vegetables is around 6.5 to 7, which is the pH at which most nutrients held in the soil are readily available to the growing plant. Determine your soil’s pH with a simple test using a pH test kit (available at Bunnings Warehouse, garden centres and hardware stores).

  • Collect small soil samples from the garden to test. Mix the samples together then sprinkle over the reactant from the test kit.
  • The reactant changes colour to reveal the soil pH. Check the colour change in the reactant against the pH scale.
  • If the soil pH test indicates that soil is too acidic or too alkaline for good plant growth it can be amended to bring it closer to a neutral pH (7).

Soils pH can be changed by adding either lime or acidifying agents. Follow the directions on your soil pH test kit but generally:

  • Where soils are very acidic (5.5 or below) add of lime. Work it in and retest the soil over time.
  • Where soils are highly alkaline (7.5 or above) the addition of iron sulfate, aluminium sulfate or liquid sulfur, lowers pH for a neutral to acidic soil.
  • Follow product instructions and retest the amended soil.