Mulch Is the Stuff of Nature!

Mulch! It’s becoming increasingly popular, and for good reason! It’s an essential layer for plant life. What’s more, it’s produced by plants themselves! But which plant materials are suitable for our crops? Which crops benefit from it? How thick should it be? When is it necessary? How should mulch be applied? Is it just another fad to get us to spend more money?

These are all relevant questions that I will answer by approaching this important topic from an environmental perspective rather than as a gardening technique competing with other techniques that do not use mulch.

Mulch from an environmental perspective

Nature does things right! Every day, all over the planet, it shows that it takes care of plants so that they can be self-sufficient in ecosystems where all living things involved benefit. From the smallest bacterium to the precious earthworm, all life contributes to the life of others in a balance that ensures life in perpetuity.

To maintain this balance, there are laws to be followed! A society without laws and rules would descend into chaos. The same is true in gardening and horticulture! If we break fundamental environmental laws, problems arise and, with them, the use of products to try to remedy them.

The Proper Uses of Mulch

The use of mulch is part of respecting these fundamental environmental laws! Mulch is also the very foundation of the entire ecosystem that benefits plants. It is part of the great cycle of life. In a cycle, there is no beginning and no end, but for the purposes of this article, let’s consider mulch as the starting point of this cycle.

In nature, when plant matter dies (tree leaves, conifer needles, grass in meadows), it falls to the ground and forms a protective layer. Although the plants from which it came are no longer using it, it is still very useful to them: it becomes a protective layer for life in the soil, regulating soil temperature and preventing soil water from evaporating.

That’s a lot, but it’s not all! A vital and often overlooked role in gardening is that mulch in nature inevitably becomes food for the plants that produced it.

Nature’s Life Cycle

Plants in nature don’t need to go to the store to buy fertilizer, compost, mycorrhizae, and other things like we do. One day, I wondered if it would be possible to care for my plants the same way nature does.

The first thing I noticed when observing nature was that wherever there are wild plants, there are always three layers of matter: soil, humus covered with a layer of dead or living plants. It’s always like that in nature! It’s like a shepherd’s pie (steak, corn, potatoes)!

Three distinct layers with well-defined and, above all, very essential roles—that’s what you need to remember! It therefore makes sense to have a surface layer made up of dead or living vegetation that hides the soil (mulch or ground cover plants).

When growing seasonal plants such as vegetables, herbs, or annual flowers, it is unthinkable to use ground cover, as it does not have time to establish itself. This leaves us with mulch. But which type?

What Type of Mulch To Choose?

There are all kinds to choose from… So what qualities does a mulch have to have if it is to be suitable and play all the roles nature intended it to play?

• It must be plant-based (no plastic or other materials).
• It must be in the same plant group as the plants to which it is applied: conifer mulch for conifers, leaf* and chip mulch for broadleaves and herbaceous mulch for garden, perennials and annuals.
• It must decompose quickly to nourish life in the soil.
• It should have little or no decomposition, not be too coarse and should remain airy.
• It must be available and require little transport (an environmental issue).
• Finally, it must be affordable, so that it’s accessible to all budgets.

*Note that leaf mulch can also be used on herbaceous crops, as its carbon/nitrogen ratio is relatively balanced.

Materials that meet these six criteria are easily found in nature and in our environment. If we must reduce overconsumption to save the planet, this is one way to do so while taking advantage of what nature has to offer! Tree leaves, all kinds of grasses, including aquatic plants that compost at the bottom of our lakes instead of in our gardens, crop residues, conifer needles, wood chips, and BRF are all materials that surround us. It’s a matter of choosing the right material for the right crop!

Now, the Thickness!

We often hear that you should put down 5 to 10 cm [2 to 4 inches] of mulch. I’ve often wondered, “Where did that come from?”

From an environmental standpoint, I have never seen such thick layers of leaves or needles in forests or so much dead grass in wild meadows! Imagine mulching your little carrots in the garden or your annual flowers in your flower beds with 10 cm [4 inches] of material!

Nature adds only a thin layer of material, rarely more than 1 cm (1/2 in) per year, but it adds it every year, creating a layered structure of material in various stages of decomposition, which provides a regular but not excessive supply of nutrients to plants.

What happens when you use 5 to 10 cm [2 to 4 inches] of mulch?

• Excessive carbon input affects soil balance, particularly the availability of nitrogen for your plants.
• The soil will stay cooler in summer because mulch insulates. While it is recommended to cover frost-sensitive plants with mulch in winter, the same applies in summer to prevent the sun from heating up the soil.
• The risk of root rot in certain plants increases.
• In a vegetable garden, too much material on the surface becomes a nuisance the following spring, as it has not all decomposed, especially if it is carbon-rich material.
• Imagine the volume of material needed to cover a garden to a depth of 5 to 10 cm! It’s environmentally unsustainable! How can you expect nature to provide so many resources when you harvest so little and so little returns to the soil?

Devant cette évidence de la nature, la seule raison que j’ai trouvée et qui justifierait l’emploi de tant de paillis serait de répondre à cette tentation forte de notre système économique à surconsommer des produits qui se vendent.

My Recommendations

To conclude, here are my recommendations:

• Prioritize the resources nature gives you.
• Prioritize mulching rather than composting. This will increase their usefulness and reduce your efforts and expenses.
• Apply between 2 and 3 cm thick (1 inch), adding more as needed when the thickness falls below 1.5 cm (1/2 inch).
• Never leave soil bare, unless you really want to weed, water, hoe, fertilize and manage growing problems caused by plants stressed because the “natural shepherd’s pie” isn’t in place.

Happy gardening!