Mulch Uncovered

Mulch is a layer of material placed over the top of your soil.  It’s usually organic matter and can range from pine bark to leaf mould, straw and sugar can, but can also be inorganic and include materials like pebbles.  So why does your garden need a blanket in summer?

Mulch acts in a variety of ways.  It stops water from evaporating from the soil as easily, it supresses weeds, it can provide some nutritional benefits and it can also be ornamental.  If you have mulch on the garden as a thick blanket layer, between 5cm and 10cm thick, it also helps keep your soil temperatures constant, which is very important in extreme weather.

So which mulch is best to dress your garden? This depends on what you’re growing.  Vegetables love a nutrient rich mulch like cow manure or mushroom compost, and also lucerne and sugar cane, which are also a great mulch are great for perennials and roses, as it gently provides them with nitrogen as it breaks down. Trees, shrubs and ornamentals can be mulched with longer lasting products like tea tree mulch, red chip, leaf mould or pine bark fines.  Cactus and succulents do well with pebbles or gravel.  These also look particularly beautiful in pots and containers, as there are some incredible colours and sizes available.

A mistake often made is to mulch with grass clippings before they are composted.  They can form a thatch that’s very difficult for water to penetrate and are best broken down first into humus by popping them in a compost tumbler, worm farm or compost heap first with some larger matter like old leaves. Then apply to established garden beds.

Make sure you weed and water well before applying, and keep mulch away from tree trunks, which can cause rot if it builds up around were the trunk meets the soil.  The best time to apply mulch is before any temperate extremes.  This normally means before summer and again before winter.  However it’s not a time critical job, and if you see your mulch has become sparse, reapply otherwise it will be ineffectual.