MULCH MULCH MULCH!!! It is important to mulch: 1) It keeps weeds down, mainly by blocking out light they need in order to germinate, 2) It conserves soil moisture by reducing evaporation, 3) It Moderates the temperature in garden beds; keeps them cooler in the summer and reduces the risk of damage to plant roots in the winter, 4) It keeps the soil from splashing onto loeaves when garden bed is watered, 5) Organic mulch adds all-important humus to the soil as it decomposes, and keeps the top layer of soil loose and airy.