The magic of mulch

Sunny, hot weather usually cues us that we need to get out and top up the mulch in our garden beds. But there are other reasons why your should mulch (or top up your exisiting mulch layer) at the start of summer. Here’s a few other benefits that mulching will bring:

• Regulate soil temperatures - Mulch helps to regulate soil temperatures and supports plants that are coping with extreme weather. A mulch layer reduces heat absorption and will be cooler than soil directly exposed to sun.

• Prevent moisture loss. Moisture loss occurs when the sun causes evaporation. But windy weather can also dry out the soil and stress your plants.  

• Help prevent spread of disease. Mulch provides a physical barrier that protects against soil borne diseases. For example, mulching under roses can help stop black spot fungal spores in the soil from being splashed onto the leaves during a rain event.

• Suppression of weeds. A mulch layer will block light and therefore prevent many seeds from germinating.

• Improves soil. Some mulches such as pea straw are high in nitrogen and as it breaks down this nitrogen returns to the soil increasing nutrient content available to plants.

• Protects from soil erosion. Without a layer of mulch covering the soil, top soil can run off your garden beds during heavy rain events.

• Increased production. Studies have shown that plants grown in mulched beds grow faster, contain more chlorophyll, and greater root growth. If you are growing fruit and vegetables, you will harvest more food from a crop that has been mulched.

• Indirectly, mulch can help reduce insect activity. By helping plants to improve their overall health, they become less susceptible to insect attack.

Types of mulch

There are many different materials you can use for mulch and you will find something suitable for every garden. 

• Straw mulches (Pea Straw, Lucerne Hay, Sugar Cane) - great for the veggie patch, they can be bought in compacted bales. The hollow centres of the straw also has an insulating effect. Pea straw contains nitrogen that will break down into your soil, improving the overall condition.

• Bark mulch - inexpensive and lightweight, bark mulches are easily spread over the garden. Larger chunks of bark will take longer to break down, but may blow away in windy weather. Bark mulch is not the best choice if using it in the vegetable garden, as it can pull nitrogen away from the plants.

• Stones/rocks/gravel - gravel mulches are great for their water holding capacity, and also providing warmth to soil. In winter this can help support plants that don’t like cold.

• Lawn cuttings. You can use dried grass clippings on your ornamental garden or veggie patch. This will break down and provide a good source of nitrogen. Just don’t use cuttings that have invasive weeds or if you have sprayed your lawn with herbicides.

• Leaf litter from deciduous trees - if you have a deciduous tree, you have free mulch! In autumn, throw your leaves onto the soil and it will break down into a beautiful soil conditioner. Why waste such an amazing natural resource!

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Gravel mulch

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bark mulch

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straw mulch

Some tips for mulching your garden

• A good guide to how much mulch is to apply around 5-10 cm layer of mulch

• Make sure the soil is damp when the mulch is applied, and then water the mulch once you have laid it out

•  Avoid letting the mulch touch the stems of plants, as it can cause the plant to rot

• If the mulch becomes water repellent, soil wetting agents can be applied to rehydrate it

• When mulching trees, make sure you go right out to the canopy line to make sure you are protecting any shallow roots
  

Let’s talk about dirt!

Give your soil some TLC

It’s spring!  We all get so excited when the sun comes out and buds seem to appear overnight on our favourite plants.   Sometimes it actually feels like you could sit and watch the grass grow!  All this energy that the plants put into growing has to come from somewhere. 

It comes from the soil.  A plant could be in the best position in perfect light, with ready access to water.  But all the TLC in the world won’t help if you don’t look after its lifeline.  So now is the time to give it a transfusion.

 Improving your soil

Spring is a great time to focus on improving the soil conditions in the garden.  Plants will put on the majority of their growth in spring, so feeding in September will help get the most out of this active season.

We could talk about soil all day (yes, really!) but we won’t bore you with all the dirty details (unless you ask us)!  What we can do though is give you some basic tips that you can use to get your garden soil ready for an amazing spring.

Understand what type of soil you have

Knowing your soil type will help you figure out how to improve it.  If your soil is sandy, you will have great drainage but the soil is likely to be very low in nutrients.  At the other end of the spectrum is clay.  If you have clay soil, you are lucky in one way as clay is very high in nutrient. But it drains very slowly and can be hard for plants to access the nutrients (you may have sodic soil).

One way to quickly check the soil type is to grab a handful of wet soil and squeeze it together. Can you mould it into a ball and it stays in shape?  Then you are looking at clay.  Does it run through your fingers as you try and squeeze it, not sticking together at all?  Then you have sand.  If you have something that partially sticks together then you likely have a loam soil.

Sandy soils

Sand dries out very quickly, and you may need to re-wet the soil with a wetting agent. Check what happens when you add water.  Push the top layer away and check if it is still dry underneath.  If it is, it’s likely your soil in hydrophobic.  A product like Saturaid or Rapid Soak will help the soil particles absorb water. Add a decent layer of mulch to retain the moisture in the soil and this also helps moderate soil temperatures.

The other challenge with sand is that it’s very low nutrient content. Adding composts and manures puts additional organic matter into the soil and enlivens a sandy soil.  You need to add for good amount for the best effect, ideally dig it through the top 30cm of soil.  If it’s not possible to dig it right through without upsetting your plant roots, it will still be beneficial to apply it to the top layer of your soil.

Additional fertilisers are needed to supplement any nutrients the plant has used up in the previous season.  Fertilisers like a pelletised poultry manure, cow manure, blood and bone, or slow release fertilisers will also help boost the nutrient level.  Regular applications of liquid fertilisers like Powerfeed and Seasol can also be helpful.

Clay soil

Full of nutrient, clay is great, but like sand it comes with difficulties.  Clay can become sodic, and may have a pH that is more alkaline, making it hard for plants to access the nutrients.

Clay soil can be improved with the application of gypsum, which helps to break down the amount of sodium chloride in sodic soils.  Don’t worry about gypsum effecting your soil pH, it is pH neutral.

Because clay soil particles are so fine, they can cause problems with drainage and become waterlogged.  Clay can be improved by adding organic matter such as compost or manure, which can encourage worms into the area.  The worms help to aerate the soil.  This should be done every year in spring, and over time your clay soil will break down and become easier to work with.

Loam soil

Lucky you!  You are the envy of all gardeners – this is the ideal soil mix.  Loam is generally rich in organic matter, but can still be improved with the addition of compost and manures, and will still benefit from the application of mulch.

Plant to your soil conditions

At the end of the day, you need to work with the soil you have.  It’s no good trying to grow plants with a high nutrient requirement in sandy, dry soil; or Australian natives in waterlogged clay (although there are always some exceptions to these rules).

Work with nature, not against it and choose plants that will thrive in your soil.  This way you will be setting yourself up for garden success, rather than disappointment.