You’re Probably Mulching All Wrong. How To Do It Right.

how to do mulching right

Mulching is one of the most common gardening practices, yet so many landscapers and gardeners do it wrong. When done correctly, it helps to build and protect soil and support plants. And please stop making mulch volcanoes, you’re killing your trees.

The post You’re Probably Mulching All Wrong. How To Do It Right. appeared first on Big Blog Of Gardening.

mulch around hostas

Mulching is one of the most common gardening practices, yet so many landscapers and gardeners do it all wrong.

You might not think there could be a “wrong way” to mulch, but there definitely is. Mulch not only beautifies your garden and suppresses weeds, it also interacts with the soil and serves as a home for beneficial insects and organisms. When done correctly, it helps to build and protect soil and support plants.

What mulch does for your garden (besides make it look pretty).

When you apply a wood-based mulch such as pine bark, cedar chips, or wood chips to your garden beds (no landscape fabric underneath!), the mulch interacts with the soil. It promotes gas exchange at the surface and slows and aids water penetration, which reduces erosion. Mulch also slows evaporation and reduces soil compaction, as foot traffic doesn’t come into direct contact with the soil. Over a number of seasons, the wood mulch slowly breaks down with the help of fungi at the soil surface, providing a type of composting.

But unlike composting, the breakdown of mulch is similar to how new soil is made in a forest. In woodlands, wood and leaves that fall from trees and plants sit on the soil surface and very slowly deteriorate. While doing so, this so-called duff layer supports the diverse ecosystem near the soil’s surface and eventually becomes the humic acids that feed plants. And it’s the same in your garden – think of mulch as future soil.

Mulch is not just for decoration

Unfortunately, many homeowners view mulch as strictly decorative and that’s why inorganic products like dyed, shredded rubber “mulch” proliferate. These products do little to help your garden or its plants, and some can even become an environmental hazard. Inorganic mulches like rubber never completely break down and eventually need to be removed from gardens and shipped to a landfill. That is obviously not great for the ecosystem (this doesn’t include inorganic mulches like stone – see below).

What mulch does for your garden (besides make it look pretty).

When you apply a wood-based mulch such as pine bark, cedar chips, or wood chips to your garden beds (no landscape fabric underneath!), the mulch interacts with the soil. It promotes gas exchange at the surface and slows and aids water penetration, which reduces erosion. Mulch also slows evaporation and reduces soil compaction, as foot traffic doesn’t come into direct contact with the soil. Over a number of seasons, the wood mulch slowly breaks down with the help of fungi at the soil surface, providing a type of composting.

But unlike composting, the breakdown of mulch is similar to how new soil is made in a forest. In woodlands, wood and leaves that fall from trees and plants sit on the soil surface and very slowly deteriorate. While doing so, this so-called duff layer supports the diverse ecosystem near the soil’s surface and eventually becomes the humic acids that feed plants. And it’s the same in your garden – think of mulch as future soil.

Mulch is not just for decoration

Unfortunately, many homeowners view mulch as strictly decorative and that’s why inorganic products like dyed, shredded rubber “mulch” proliferate. These products do little to help your garden or its plants, and some can even become an environmental hazard. Inorganic mulches like rubber never completely break down and eventually need to be removed from gardens and shipped to a landfill. That is obviously not great for the ecosystem (this doesn’t include inorganic mulches like stone – see below).

Mulch volcanoes are absolutely the wrong way to mulch around trees. The mulch traps moisture against the bark and impacts the tree’s long-term health.

Just say no to mulch volcanoes! Inexperienced landscapers are notorious for this tree-killing practice. Not only does piling mulch around the base of a tree promote bark decay, but it also makes a fine home for mice, voles, and other small rodents. If that wasn’t reason enough to stop making mulch volcanoes, the tree’s roots will grow into the mulch, which means you’ll have roots growing above the soil line. This is very, very bad for the tree’s long-term health and may kill it.

Mulch should always be a few inches away from the tree trunk and never up against it, much less covering the base of the tree. Mulch isn’t needed after the first season when the tree has taken root, and after that point it’s strictly decorative. And don’t worry about grass growing under a tree – it will not interfere with the tree’s uptake of moisture and nutrients. Tree roots grow deep in the soil, far below the grasses roots.

How mulch controls weeds and helps soil.

  • Mulch blocks the sunlight that weed seeds need to germinate.
  • Mulch acts as a barrier that makes it difficult for germinated weeds seeds to become an actual weed.
  • Mulches help to reduce soil compaction, since you step on the mulch and not the soil.
  • Mulch captures water more efficiently than bare soil and reduces runoff.
  • Mulch reduces evaporation from the soil by as much as 35%.
  • Mulch buffers and stabilizes soil temperature – it keeps soil cool in the summer and protects it from deep freezes and frost heaves in winter.
  • Mulch alone can begin to build soil in as few as 3 years in areas with no topsoil (like some urban settings or recent construction sites).

What materials make the best mulch?

Are gravel and rocks considered mulch?

Stones, gravel, and other small rocks can be used as mulch, but are inorganic, so they won’t break down and contribute to building new soil. However, they do moderate water evaporation and soil loss, and can help retard wildfires near your home, so they definitely have their place.

  • Small stones stacked at least 1″ deep are excellent for weed suppression.
  • In arid areas prone to wildfires, stones and gravel are the recommended mulch at the edges of homes, as they won’t combust when fire approaches the house.
  • In temperate areas, stones, rocks, and gravel can be used decoratively as edging in a garden bed, around downspouts to slow storm water runoff and control erosion, in gravel drains, on walkways, or in areas that see heavy foot traffic or machinery (such as areas around outdoor central air conditioning units).
  • If you use stones around plants, be aware that some mixes contain limestone which will alter the soil pH and may cause growing problems with some plants.