Mulching your garden in the fall is one of those “best practices” that is often forgotten at the end of the season when you’re ready to have a break from garden chores. If this sounds like you, it’s time to dust off your mulch pile (or find some!) because you can put it to good use in the fall.
Spreading mulch over your garden in the fall is one simple way to prepare it for the winter season and early spring.
Mulching in the fall can help prevent weed growth, build organic matter over the winter months, avoid erosion from rain, and help prevent damage to plants from winter freezes. Mulching in the fall will protect your garden through the winter and set it up for success in the spring.
Keep reading to find out why you prioritize this chore as you put your garden to bed for the season.
5 reasons to mulch your garden in the fall
You can and should mulch in the fall to help protect your garden soil over the winter months. Fall is an excellent time to mulch because it will help prevent weed growth while preventing erosion, building organic matter in the soil, and protecting plants from frost damage during the winter.
1. Prevent weed growth
Applying mulch to your garden beds helps prevent weed growth by blocking sunlight. Weed seeds need light to germinate and grow, and placing mulch on the soil surface will provide the required barrier to keep them in darkness.
Make sure you’re using an organic, weed-free mulch when you place it on top of any part of your garden soil where your plants are. Otherwise, you defeat the purpose. Stay away from hay, which is dried grass stalks and seeds.
2. Build organic matter over the winter months
One of the best things you can do for your garden soil is to add more organic matter. Studies have shown that an increase in organic matter will directly correlate to greater soil quality and better harvests. Healthy soil = healthy garden!
Any organic material will do, from leaves to woodchips. Those materials will slowly break down in place over your garden beds, adding nutrients back into the soil. However, this process takes time, which is why it’s best to apply mulch in the fall.
In addition to mulching, leaving old plant debris contributes organic matter, builds soil health, and provides food and shelter for overwintering wildlife. You can read more about skipping your garden cleanup in this article: You Should Leave Dead Plants In The Garden For Winter (Here’s Why).
My favorite garden soil supplies
When you know what condition your soil is in, it’s much easier to add anything that’s missing before your plants start to suffer.
- Find out your soil’s pH and macronutrient levels with an easy soil test kit.
- Even without a soil test, worm castings are a safe bet to add to any garden, and your plants will love them. Wiggle Worm Soil Builder is a high-quality amendment that I add to all my garden beds that need a boost.
- I often reference Farmer Jesse of The Living Soil Handbook on this blog. He’s a professional farmer with tons of information about soil science and how to build a healthy garden.
Find the rest of my “use on the daily” garden gear on my resources page.
During the winter, mulch will help protect against soil erosion from rainfall and other harsh weather conditions. It acts as a protective barrier between your garden soil and the elements. This is especially helpful if you live in an area fall rains are frequent or heavy.
Instead of hitting bare soil that can easily wash away, the rain is dispersed through the mulch and percolates down to the ground below.
4. Protect plants from frost damage
Mulching your plants in the fall will help insulate them from the cold winter air, but only if you apply mulch before temperatures reach freezing. If plant roots are exposed to freezing temperatures for too long, they can be injured or killed.
The mulch acts as insulation, bringing up the soil temperature just enough to potentially mean the difference between a plant surviving the winter or not.
Frost heave is a concern for areas with repeated freeze-thaw cycles during winter. Frost heave is when plant roots are forced upwards by the repeated freezing of the ground, breaking plant crowns and damaging roots.
Yet another reason to make sure you apply mulch before the temperature starts dropping, rather than waiting for spring.
5. Repurpose fall yard and garden waste
You can move your garden toward a closed system by reusing materials from your yard and garden as your mulch material. Fall is the perfect time to do so since you’ll have plenty of plant debris, fallen leaves, and trimmed branches on hand.
For example, as you pull up old vegetables, you can either “chop and drop” them in place or throw them on the grass and run them over with your lawnmower. The result will be a fine mulch that you can spread over your garden beds.
An added benefit is that you’ll get the added nutrients from your recycled materials through decomposition, which will directly improve soil quality. If you have any extra, toss it in your compost.
Just be sure to exclude any leaves or old plants that show signs of disease. There’s no sense in giving something like powdery mildew any help to spread through your garden!
Don’t toss those dead plants!
- Get some ideas here on how to put large stalks and branches to work: 7 Ways To Repurpose Dead Sunflowers (Seeds, Stalks, and More)
- Leaving roots behind is another way to keep valuable resources in your garden. Find out why in this article: Should You Remove Old Roots Before Planting? (Nope, Here’s Why)
What type of mulch should you use?
There are several options available when it comes to mulching in the fall. Your material must be organic because it will help support the soil’s biology over the winter as the mulch breaks down.
Some people prefer to use two or more types of mulch. It comes down to what materials you can source easily.
Some of the most common organic mulches are:
- Grass clippings
- Shredded leaves
- Wood chips
To help you decide which mulch to use, check out this article I wrote for more details: Best (Free!) Organic Mulches For The Home Garden.
How much mulch should you apply in the fall?
You’ll want to apply a layer of mulch that’s 3-4 inches deep after you’ve cleared out your garden of anything that’s not going to overwinter, such as annual flowers, vegetables, and trimmed portions of perennial plants.
It’s always better to start with too much mulch than not enough, so err on the side of applying more, even if that means getting creative with leftover mulch materials.
If using grass clippings or leaves, make sure they are dry when you apply them so you can spread them out easily. If these materials blow away as they start to dry out, you can hold them in place with branches or even boughs from your old Christmas tree.
Keep a 2-inch ring clear around the plant stem as you apply the mulch. Doing so will help prevent the stem from rotting if it gets too moist once winter sets it.
The very top of your mulch should be even with the soil line (if you had to dig anything around before mulching), but for shrubs and perennials that produce new growth every spring, you’ll want to leave some space between the
Mulching is a simple but beneficial task for fall gardening, so don’t forget to get it done before the weather gets too cold!