The Magic of Mulch

It’s difficult to understand the importance of mulch, or even how to properly use it, when there are so many bad examples around our city. When parkway trees have mulch volcanos piled close to the trunk or urban farms have mostly bare soil, it’s hard to know what the best practices are for this important resource.

img_5066

Although the materials are on the right track, there are problems with this style of sheet mulching.

Although tended vegetable beds are hardly part of a natural habitat, it’s good to think about the processes that contribute to healthy, self-sustaining environments and try as best as possible to mimic them. Every autumn, deciduous trees drop leaves on the soil in the forest, creating a thick layer to help with moisture and nutrient retention; provide habitat for beneficial microbes and macrobes; insulate against fluctuating temperatures and frost heaving; and gradually decompose, adding organic matter to the soil. This is exactly what you want to try to do in your own garden.

This fall, cover your vegetable garden beds with a 2-4″ thick layer of plant-based materials, such as deciduous tree leaves, cocoa shell mulch, straw, uncomposted plant material (such as corn stalks), or even jute coffee sacks. Although dyed shredded bark, recycled shredded rubber, gravel, and large pebbles are sold in the mulch section at the garden center, not all of these contribute the basic functions of mulch in the garden. Not only does the mulch material matter, but the size of the material affects whether the mulch will be effective. Shredded wood chips (undyed, not bark-based) are great, especially for perennial beds, while sawdust is not.