Mulch is an important component to soil-based gardens. Whether you’re using raised planters or gardening directly in the ground, mulch plays a key role in the quality and health of your soil. But to know what mulch will work best for your situation we must explore the different types of mulch and how they work in the garden.
Mulch is any organic material used as a protective layer over your soil, similar to how a forest floor is covered with dead and dying leaves. It creates an insulative barrier over your soil which helps control temperature, promote water retention, develop soil structure, aid in nutrient delivery and creates an ideal environment for natural biota that support soil health. The right mulch will also reduce erosion and crusting of the surface soil and reduce the impact of invasive weeds.
Ultimately, there are three main factors that we use when choosing a mulch for our gardens. We look for a material that is natural (no chemicals), plentiful, and cheap. Our gardens in the Edible Learning Lab and in our personal gardens all make liberal use of locally harvested wood chips and dead leaves. Wood chips from local trees are generally very clean (depending on season and source) and most of the time you can get whole truckloads of wood chips for next to nothing (if not actually free). During the fall, turning leaves from deciduous trees litter the ground and can be collected and used as a mulch or as a great Brown (carbon) addition to your compost.
Lay down your mulch in a thick layer. We can’t stress this enough, especially in harsh climates. The more mulch you can lay down, the more protected your soil, and the life within it, will be. In our gardens we shoot for between 4″ and 6″ of mulch cover. For mulching around trees we shoot for even more, sometimes as much as 12″-14″ of mulch.
If you are growing evergreens or berries that may want more acidic soils, and you live near a wood mill, sawdust might be a good option for you. Or maybe you live near a ranch that has a ready supply of straw (not hay!), which would make it plentiful and cheap. Straw makes a great mulch in protected spaces and edible gardens, just know that there are some challenges to using straw.
To learn more about how mulches work, learn about different types of mulches, and explore their benefits and challenges we recommend you visit this page on Mulches For Landscapes from the Cornell University Department of Horticulture.
Benefits of Using Mulch
- Insulative barrier over your soil
- Helps control temperature
- Promotes water retention
- Develops soil structure
- Can help balance soil pH
- Aids in nutrient delivery
- Creates an ideal environment for natural biota
- Reduces erosion and crusting of the surface soil
- Reduces the impact of invasive weeds