- GREENFUTURE -
MULCHING AND ITS IMPACT ON MOISTURE RETENTION

The main mechanism behind moisture retention lies in the creation of a protective layer that covers the soil and prevents direct evaporation of water. Without mulch, sunlight and wind rapidly dry out the top layer of soil, particularly during summer. Mulch reduces soil surface temperature, maintains a more stable microclimate around plant roots, and prevents the formation of a hard crust that hinders water penetration. As a result, moisture stays in the soil longer, and even during hot weather, plants receive adequate hydration. Additionally, mulch allows for more even distribution of rainwater and irrigation, minimizing losses due to runoff.

Different types of mulch have varying effects on moisture retention. Organic mulch — such as wood chips, bark, straw, compost, grass clippings, and fallen leaves — has a porous structure that absorbs and holds water near the roots. As it decomposes, it also enriches the soil with organic matter, improving its ability to retain moisture. Inorganic materials like gravel, expanded clay, and decorative stones can also reduce evaporation, especially when applied correctly, but they do not nourish the soil. These are often used in areas where aesthetics are a priority. Geotextiles and garden fabrics are frequently placed beneath organic mulch to enhance its moisture-retaining properties. Choosing the right mulch depends on site conditions, climate, and landscape design preferences.

In addition to directly retaining moisture, mulching has a broader impact on overall soil health. It suppresses weed growth, reducing competition for water. Mulch also limits soil compaction caused by rain or irrigation, helping roots to breathe and absorb moisture more efficiently. Another key benefit is protection from erosion: mulch softens the impact of raindrops and wind, preventing the topsoil from being washed away. In winter, it insulates the soil and protects it from deep freezing, which means moisture remains accessible for longer in early spring.