CHENNAI: Most organic gardeners and farmers rate mulching as one of the top activities you should be doing to get your soil’s life back. Mulching is probably the cheapest and easiest way to improve your soil quality by leaps and bounds.Mulch is any material that can be placed on the surface of the soil. This process of mulching has many benefits. While many conventional farmers use plastic mulch, it does not benefit the soil as much as organic mulches do.
Mulch reduces evaporation of water from the soil, thus reducing the amount of water you need. According to some estimates, you can reduce your water requirement to almost a quarter by just having enough mulch spread over the soil.A layer of mulch also prevents weed seeds from germinating by smothering them or by depriving weeds of sunlight, while the taller plant crops have access to it. Weeding is effort intensive, and we do not recommend using ‘weedicides’ because that ends up killing a large portion of the soil life along with the weed. By mulching extensively, you can substantially reduce the effort needed for weeding.
Mulch also helps maintain the soil temperature by acting as a cooling layer. Mulch helps protect against soil compaction by not letting heavy rains hit the soil directly.
But the most important reason for using mulch is that it provides nutrients and shelter for soil food web organisms. Worms in the soil food web munch on organic matter in the mulch, resulting in nutrient-rich worm castings and wonderfully aerated soil due to worm tunnels, and so on. Mulch also provides shelter for earthworms during those hot sunny days, and instead of crawling back deep into the soil to avoid the heat, they can stay near the surface. The mulch material provides food for the micro-organisms, which causes it to decay, adding organic matter back into the soil.
What materials can be used as an effective mulch? To decide this, you need to consider the type of plants that you are trying to grow. In general, plants like vegetables, annuals, grasses etc do better in soil that is dominated by bacteria, while trees, shrubs, perennials do better in soil which is dominated by fungus. So, the materials you choose for mulching, must be decided based on whether you want your soil to be fungally dominated or bacterially dominated. There is a very simple way to distinguish between mulch materials which help fungi thrive versus those that help bacteria thrive — a mulch of fresh green organic materials like grass clippings, helps bacteria flourish; while a mulch of aged, brown organic materials like dry leaves, helps fungi thrive. If you are going to have a mixed garden with all sorts of plants, you may want to create a mulch mixture with both brown and green organic materials.
How should you spread the mulch? Again, this depends on whether you want to have your soil dominated by bacteria or by fungi, as per the plants you plan to grow. If you spread the mulch on the surface of the soil, that usually helps fungi; while if you work the mulch into the soil with any gardening tool, that is usually better for supporting bacteria.You need to be careful of a few things while spreading mulch. First, keep some space between the stem of the plant and the mulch — don’t put the mulch right up against the stem of the plant because it can cause some decay on the stem or trunk. Second, do not go overboard with the thickness of the mulch layer on the soil, making it much thicker than three inches or so, can end up blocking air from the soil.What if you were planning to use compost? Simple, put down the compost first on the soil, and cover it on top with mulch. Happy mulching!
The author is the CEO of Farmizen, a platform connecting organic and natural farmers to urban consumers with same-day farm-to-fork delivery.