New to gardening? If you have heard of ‘mulch’ and ‘mulching your garden’, but you have never done it, the following simple Q&A offers simple answers to the most common ‘gardening newbie’ questions.

What is ‘mulch’?

Mulch is a layer of organic material put down on top of soil prior to planting. It can also be laid down seasonally around existing plants (e.g. fruit trees), over newly planted or bulbs that have died back at the start of winter.

Common mulches includes:

  • Wood chips
  • Straw
  • Vegetable composts

What does mulch do?

It does several things:

  • It helps soil retain moisture
  • Insulates soil during the winter months.
  • Mulch can help ‘feed’ the soil, improving the nutritional content along with fertilisers, or, in some cases, instead of fertilisers. It can also helpt so stabilise soil PH.
  • Depending on the type, it can be a more attractive bedding substrate than soil. This is especially true for new plant beds and vegetable gardens. Wood chips are ideal for this purpose.

How does mulch work?

Mulch works by:

  • Creating a physical barrier between the topsoil and the sun and wind. This stops the soil drying out – whether from heat or wind-driven evaporation. It also helps to stop finer soil particles blowing away in the wind.
    This physical barrier can also help cool the soil on hot days, and keep it warm on cold days (though not frost days or in very low temperatures!)
  • Decomposing. As it breaks down, it becomes a compost for your plants, adding extra nitrogen and other micro-nutrients to the soil. The process of decomposition is driven by fungi and other microbials that break it down. This not only helps deliver more of the elements that plants need to thrive; it makes those minerals bio-available – i.e. the plants are better able to absorb and utilise them.
  • The course texture of mulch helps to stop weeds from growing, This is because most seedling sprouts cannot make it through most garden mulches. Unable to reach the sun, the first nursery leaf (cotyledon) is unable to get sun, and the seed stops growing and dies.

Is mulch really necessary for your garden?

Garden plants, herbs and vegetables need sun, water and good substrate with mycorrhiza (the right fungi and fungal network) and the right PH soil with an optimal balance of minerals to grow. They do not need mulch. However, the role that mulch plays in growing healthy plants is not to be underestimated. It’s not ‘essential for growth’ but it is essential for conditioning the soil and ensuring that it doesn’t dry out too quickly – and these factors are what makes mulch an essential ingredient on your garden bed and veggie patch.