This photo is worth a thousand words. Over the years, in an attempt to have a neat and clean yard, we remove the leaves from our garden. Here, shade has prevented a healthy covering of turf. Without something covering the ground, rain has washed the organic components out of the exposed ground. What is left is a barren, stony subsoil where no seed can germinate, no roots can penetrate.
So, Why Mulch?
Mulch serves so many purposes for gardeners. It adds a layer of insulation to the earth, reducing moisture loss due to evaporation. That’s so important in our long, hot summers. Mulch also slowly adds organic matter to the soil, improving soil tilth and texture, as well as improving soil moisture retention. Mulch will work with the soil to provide a matrix for microbes and beneficial fungi to vastly improve soil fertility in ways impossible to do with the chemical fertilizers. Plant roots respond readily in well mulched soil.
Mulch is not always organic (think gravel or shredded tires), but for best results, go with compost or leaf mould. Pine straw provides excellent insulation and breaks down quickly to increase the organic component in our soils. Pine bark is also good on flatter gardens, but may wash away on slopes. Avoid using cypress mulch as it is absolutely not sustainable. Since most of us do not have trucks to haul this stuff back home, we rely on bagged product available at the big box stores. Product labeled “potting soil” or “grow mix” is mostly pine byproduct, and is a superior top dressing around garden plants, if you can afford it.
You can always produce your own leaf mould for use as mulch, but this takes LOTS of leaves and a compost area. I directly apply leaves stolen from my neighbors in ready to travel black plastic bags, but I have a truck. But the point remains: cover that bare earth.