Mulching is an essential component of the garden that is often overlooked. It can save time in the long run by reducing time spent weeding, watering, fertilizing, and controlling pests. Let’s look at some of the commonly asked questions: What is mulch, how to mulch, and types of mulch.
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Mulching: An Extra Task?
Strapped for time, many of us busy gardeners barely find time to plant and harvest, let alone keep everything weeded. When it comes to mulch, it just seems like an extra task on the to-do list. Luckily, mulching will save us time in the long run by creating a healthier ecosystem and reducing the amount of time required for other maintenance tasks.
WHAT IS MULCH?
Mulch is a biodegradable layer of organic material added to the top of soil in a garden or landscaping. In the permaculture garden, mulch mimics the forest floor, which is usually covered with herbs and shrubs, sticks and twigs, and leaf litter.
In nature, bare soil equals damaged soil.
Mulch does all of the following good things:
- Retains moisture
- Prevents erosion
- Creates humus
- Suppresses weeds
- Makes an attractive top dressing
Note: Your mulching practice will have a lot to do with your climate and season. Gardeners in hot/dry climates will mulch more thickly to retain more moisture and protect from the hot sun. Gardeners in cool/wet climates will use a thinner mulch that will protect the soil from washing away while allowing excess moisture to evaporate to reduce fungal issues.
In my climate, where we have cool/wet springs and hot/dry summers, I mulch lightly in the spring and thickly during other times of the year.
Mulch is a crucial element in the no-till garden.
TYPES OF MULCHES AND THEIR USES
In this article, I’m going to focus on using plants and free materials as mulch. I’ll review types of mulch such as living mulch, green mulch, leaf mulch, and what I call my ‘magic mulch combo’.
Living plants–either annual or perennial–planted underneath a primary crop will help to suppress weeds, retain moisture, reduce soil erosion, and create habitat for beneficial insects.
Use annual plants as mulch in the vegetable garden, and perennial plants as mulch under perennial crops such as fruit trees.
Many people wonder whether a living mulch will smother the primary crop. Consider the forest or prairie, where plant species naturally grow intertwined or close together. Different plants have different root structures – some are shallow and wide, while others are narrow and deep. Various roots usually occupy different strata of the soil, so they don’t compete for nutrients.
A Few Examples of Living Mulches
Green mulch is also called “chop-and-drop” mulch: Green weeds or other plants that are cultivated to protect bare soil and provide nutrients (fertilizer) to major crops.
Have you ever wondered why many of those pesky weeds have such deep taproots?
Dandelions, for example, heal bare earth by dredging up nutrients with its deep roots. We can take advantage of this free and abundant resource by mulching and fertilizing with dandelion leaves. Learn more about weeds: when weeds are good and 5 weeds you want in your garden.
Common Green Mulches (Many are Weeds)
Lamb’s Quarters (5)
(#) indicates the number of nutrients the plant accumulates in its leaves
Chart information above is taken from Gaia’s Garden: A Guide to Home-Scale Permaculture, 2nd Edition
To use weeds for green mulch, cut them at the base, leaving their roots intact to feed beneficial soil organisms. Chop the green matter roughly into 2-3 inch pieces, and lay the green mulch on top of the soil beneath (but not touching) the garden crops. For a more attractive look, green mulch can be topped with a layer of leaf mulch or wood chips (see ‘Magic Mulch Combo’ below.)
Leaf mulch is an attractive top-dressing in the garden, but also helps retain moisture. We collect leaves from many of our neighbors, shred them with the lawn mower or leaf mulcher, and pile them in wire bins for use throughout the year.
Walnut leaves should not be used, as they have a chemical called juglone that suppresses healthy plant growth in all but a few plants. Oak leaves should be used only when mixed with other leaves because they break down slowly and contain tannins that can affect the soil composition.
Leaf mold (leaves that have composted for 2-3 years) is an excellent soil conditioner. At Hillside Community Garden, leaf mold is an essential component of our soil mixture. This saves us from purchasing compost soil for our expanding garden.
Wood chips can be delivered–often for free–from local tree services (giving the driver a tip may ensure more in your future!). Wood chips are a perfect mulch to use around perennials. They should never make contact with the stems or trunks of the plants.
Wood chips that have broken down for 2-3 years are a gold mine of a soil conditioner. Use them without caution in the vegetable garden, under fruit trees as an attractive top dressing, or in the ‘Magic Mulch Combo’ in place of leaves.
*Magic Mulch Combo*
A study was done at Michigan State University in the 1990s that researched leaf mulch and whether it contributed to weed suppression or fertilization. The researchers found that leaf mulch did not serve much value as a weed suppressor or fertilizer source by itself.
When coupled with a nitrogen source (think green mulch), the weed suppression and fertilization levels went up. So I’m a proponent of composting in place just like you would in your compost bin, by layering the greens and the browns.
Though I use many types of green mulch around the garden, my favorite combo is using the abundant grass clippings from my neighbor. We piled them thickly–about 1 to 2 inches–in the garden beds (but not touching the plants) and topped with an equally thick layer of shredded leaves.
The gardens are happy, I’ve kept more organic material out of the waste stream, weeds are few, and it looks appealing with the leaf mulch on top. It also solved my problem of not having enough room in the compost bins to accommodate all of the grass clippings from the neighbors.
Preparing the Garden for Winter
Another ‘Magic Mulch’ option is using composted animal manure (horse, cow, chicken, rabbit, etc.) in place of green mulch. In the fall spread a thick layer of composted manure over the beds and top with a layer of shredded leaves or composted wood chips. This will not only protect the soil from the harsh winter temps, but it will also help to improve soil quality.
Note: Ask questions about the origin of the manure. Unfortunately, manure can be laced with herbicides if the animals ate from pasture that was sprayed, or it can contain pharmaceuticals.
More mulching ideas:
All in all, mulching is an important component of lasting soil health, water conservation, and time savings for the gardener. When the soil is happy, the plants will be happy, too, and you will experience fewer pest problems. You’ll thrive as a gardener, and will regenerate your soil’s fertility over time. This is part of the process of connecting to our place as active residents.
What’s your favorite way to mulch?