A good layer of mulch is essential for a healthy yard. It regulates soil temperature, blocks weeds, and holds moisture in the soil, but knowing when to add a fresh batch is key to reaping the full benefits.
Mulch replacement isn’t one-size-fits-all — it depends on the type and its durability. Organic mulch breaks down more quickly and typically needs to be replaced every 1 to 2 years, whereas inorganic mulch can last for 5 to 10 years.
We will break down the types of mulch available and share some simple ways to determine when yours needs replacing.
Organic mulch
Organic mulch refers to any material that naturally decomposes over time and is used to cover the soil surface, including wood chips, shredded bark, straw, compost, leaves, and pine needles. They are great at retaining moisture, blocking weeds, improving soil texture, and regulating soil temperature.
Since organic mulch breaks down, you’ll need to reapply it every 1 to 2 years, depending on the type. Heavier rain, strong sunlight, and the thickness of your initial application all impact how quickly it wears down.
Organic mulch is readily available at garden centers, home improvement stores, and landscape supply yards. Many cities also offer free mulch made from chipped yard waste — check your local public works or composting program for details.
| Organic mulch type | How often to replace |
| Bark chips/nuggets | Every 1 to 2 years |
| Wood chips | Annually |
| Pine needles | Annually |
| Shredded leaves | Twice yearly |
| Grass clippings | Monthly |
Read more:
Bark chips/nuggets
- How often to replace: Every 1 to 2 years
- Cost: Bulk from $30 to $70 per cubic yard or bagged from $4 to $12 per 2-cubic-foot bag.
Made from durable tree bark that resists decomposition more than other types of organic mulch, bark mulch is great for around trees or shrubs where you don’t want to constantly replace it. However, they tend to move around if you live in a windy, rainy, or sloped area.
The lifespan of bark mulch depends primarily on your local weather conditions. In areas with high rainfall or humidity, it can break down more quickly or be washed out of place. Bark nuggets, in particular, tend to float during heavy downpours, so they might scatter or thin out even if they’re still holding up structurally.
My tip: If you really like bulk mulch but want it to last longer, opt for large, chunky pieces. They are more durable and can last up to 4 years.
Read more: How to Mulch Around Trees
Wood chips
- How often to replace: Annually
- Cost: Bulk from $20 to $50 per cubic yard or bagged from $3 to $9 per 2-cubic-foot bag.
If you want mulch that lasts without much upkeep, wood chips are a solid choice. They keep things tidy, help the soil stay hydrated, and control pesky weeds. However, since they break down slowly, they don’t add as many nutrients to the soil as faster-decomposing mulches, such as leaves or grass clippings.
To get the most out of wood chips, aim for a 3-inch layer. Too much can choke your plants, and too little won’t block weeds effectively. Once that layer has broken down, you can reapply.
Pine needles
- How often to replace: Annually or once every two years.
- Cost: Bulk from $35 to $65 per cubic yard or baled from $6 to $15 per compressed bale.
Pine needles, also known as pine straw, are a durable, low-maintenance organic mulch that lasts well. Their long, needle-like shape helps them stay in place better than some other mulches, making them perfect for windy or erosion-prone areas.
In areas with high moisture, pine needles can become matted and dense, reducing their effectiveness in holding moisture and preventing weeds.
Shredded leaves
- How often to replace: Twice yearly
- Cost: Bulk from $25 to $40 per cubic yard or bagged from $3 to $7 per 2-cubic-foot bag.
If your yard has trees, you may have the opportunity for a free mulch supply. However, shredded leaves break down quickly, and you’ll need to replace them a couple of times a year, especially in places with lots of rain or snow.
Shredded leaves are packed with nutrients and do wonders for your soil. Unlike wood chips or bark, which primarily cover the ground, shredded leaves actually nourish your soil as they decompose, making them ideal for garden beds, flowers, and vegetables.
My tip: Before spreading, mulch your leaves with a mulching mower or shredder to keep them from matting together. Use as much as you need and store the rest for later.
Read more:
- What to Do With Fall Leaves on Your Lawn
- The Best Way to Remove Leaves From Your Yard
- Is it Better to Rake or Mulch Leaves?
- 8 Best Mulching Lawn Mowers of 2024
- Benefits of Using a Mulching Lawn Mower
Grass clippings
- How often to replace: Monthly
- Cost: Free from your own lawn or municipal composting facilities.
Grass clippings typically need replacement every month, depending mostly on your climate and rainfall. In hot, humid conditions, you may need to replace them weekly. However, in cooler climates, monthly replacement is enough. This free resource returns nitrogen and nutrients to your soil as it decomposes, making regular replacement both economical and beneficial for gardens and flower beds.
Keep your layers to under half an inch thick to prevent matting, and replace them when clippings have visibly diminished or discolored. As Aaron Steil from Iowa State University advises, wait at least 2 or 3 mowings before using herbicide-treated clippings to avoid introducing chemicals to your garden beds.
Read more:
- Ways to Use Grass Clippings as Mulch
- Bagging vs. Mulching Grass Clippings
- How to Compost Your Grass Clippings
- How to Prevent Grass from Clumping When Mowing
Inorganic mulch
Inorganic mulch, like gravel, rubber, landscape fabric, or plastic sheeting, doesn’t add nutrients to your soil like organic mulch. Still, it makes up for it by being super low-maintenance, long-lasting, and excellent at stopping weeds in their tracks.
Depending on the material, you might only need to replace it every 3 to 8 years. You can use inorganic mulch in xeriscaping, desert landscapes, and areas around buildings where you prefer minimal maintenance.
You’ll find inorganic mulches at garden centers, home improvement stores, and online — often in bulk or large bags. For larger projects, landscape supply companies are great options.
| Inorganic mulch type | How often to replace |
| Stone/gravel | Every 10+ years |
| Rubber | Every 8 to 10 years |
| Crushed shells | Every 3 to 5 years |
| Landscape fabric | Every 3 to 4 years |
| Plastic sheeting | Every 1 to 2 years |
Read more:
Gravel or stone
- How often to replace: Every 10+ years
- Cost: Bulk from $40 to $120 per cubic yard, or bagged from $4 to $15 per 0.5-cubic-foot bag.
Using stone or gravel as mulch is the best option if you’re looking for longevity, as it generally lasts upwards of 10 years. It doesn’t decompose, fade, or require constant applications, making it a great choice for pathways, trees, and xeriscaped areas.
Another big perk is that it doesn’t attract pests like termites or rodents, which often infest organic mulches. Just remember that stone traps heat, warming up surrounding areas. If your plants prefer cooler soil, this might not be the best option.
Read more:
Rubber
- How often to replace: Every 8 to 10 years
- Cost: Bulk from $300 to $500 per cubic yard, or bagged from $8 to $16 per 0.8-cubic-foot bag.
Rubber mulch is designed to last 8 to 10 years with minimal maintenance. Made from recycled tires, it can mimic the look of shredded wood, comes in many natural colors, and won’t fade, wash away, or attract bugs.
Additionally, with its shock-absorbing properties, rubber mulch is ideal for play areas in your yard. You can also use it around pathways and in garden beds around your home.
Read more: The Pros and Cons of Rubber Mulch
Crushed shells
- How often to replace: Every 3 to 5 years
- Cost: Bulk from $50 to $110 per cubic yard or bagged from $6 to $14 per 0.5-cubic-foot bag.
Crushed shells, like those from clams, oysters, or scallops, are a solid mulch option because they don’t rot or attract pests, and you won’t need to replace them every year. They’re perfect for coastal gardens or areas with heavy rainfall that require a drainage solution that works well.
While the shells won’t rot, they can settle or become compacted. You may notice the layer thinning or shifting, so it’s a good idea to check on it annually. And since shells can break into smaller bits over time, a little raking or leveling can help keep them looking fresh.
Landscape fabric
- How often to replace: Every 3 to 4 years
- Cost: Basic woven from $15 to $25 per roll, to commercial grade non-woven from $30 to $75 per roll.
Landscape fabric, made from woven or nonwoven synthetic fibers, is designed to be a long-lasting barrier against weeds. Still, even the best landscape fabric can wear out, shift, or become torn and frayed, requiring replacement every 3 to 4 years.
Mulch or debris on top can also create gaps where weeds sneak in. Check it every couple of years and plan to do some patching or resetting the edges if weeds start to appear.
Plastic sheeting
- How often to replace: Every 1 to 2 years
- Cost: Light duty from $10 to $20 per roll or heavy duty from $20 to $60 per roll.
Plastic sheeting is a convenient solution for a no-fuss, weed-free garden. However, its longevity can be an issue. Sun exposure can make it brittle and cause cracks, while water pooling can lead to mold or rot. In raised beds or open areas, temperature changes and roots can cause it to tear. It’s a good idea to check it annually for any damage.
My tip: Cover your plastic sheeting with a more durable option, such as stones or wood chips, to shield it from UV rays and help it last longer. The plastic will also help your wood chips last longer, as they won’t be directly in contact with your soil.
Signs it’s time to replace your mulch
Color fading: Fading color is a clear sign your mulch needs a refresh. Dyed mulch typically fades within 6 to 12 months, while natural wood mulches turn gray in about a year. Raking the top layer can revive some of the color, but if it still looks dull, it’s probably time to reapply.
Weeds are taking over: As mulch breaks down, it loses the ability to block sunlight and prevent weed germination. That’s because it starts acting more like soil, giving weeds a place to settle in and grow. If you’ve noticed weeds cropping up in previously weed-free areas, it’s likely time to refresh your mulch.
Read more:
Less depth: Over time, your mulch will thin out. If it’s thinner than 2 inches (use a ruler to check), it’s time to top it off with some new mulch. Make sure your new layer is no deeper than 4 inches.
Read more: How Deep Should Mulch Be?
Decomposition: Organic mulch – and some inorganic mulches – break down and stop doing their job. Watch for signs of fungal growth, mold, visible decay, an unpleasant odor, cracking, or a soil-like texture in the mulch.
Water runoff: If water starts running off or pooling instead of soaking in, that’s a good indication that your mulch is too compacted. When water can’t penetrate the mulch, the soil below dries out, leaving your plants without the moisture they need.
Best times to replace mulch
Replacing or refreshing your mulch at the right time can improve its effectiveness. The top times to replace it are in spring and fall. Let’s take a closer look at why.
Mulching in spring is essential because it locks in moisture from seasonal rains, keeps roots cool when temperatures rise, and suppresses weeds before they can sprout. It also gives your yard a clean, fresh look before summer.
When applying spring mulch, wait until soil temperatures are consistently above 50 degrees. This usually happens between March and early May, depending on where you live. Mulching too early can keep your soil too cool and affect plant growth.
Fall mulching prepares your plants for winter. It insulates roots from freezing temperatures, retains moisture during dry spells, and prevents soil from washing away in heavy rain or snow. It also blocks late-season weeds from sneaking in before the cold season.
Always apply fall mulch before the first frost but after the summer heat is over, generally from October to early November.
FAQ about replacing mulch
Most colored mulches are dyed with iron oxide-based dyes for red hues or carbon-based dyes for black and dark brown shades. These dyes are generally considered safe for plants and soil.
The Texas A&M AgriLife Extension recommends following this formula:
Total cubic yards = (Length feet * Width feet * (Depth inches / 12)) / 27
As an example, if your area is 10 feet long by 10 feet wide, and you want to cover it with 3 inches of mulch, you would calculate it as follows:
(100 square feet) x (3 inches/12)/27 = .93 yards
Round it up to 1 yard, and you have your recommended amount of mulch.
There are a few things you can do with old mulch:
Spread it as topdressing in your garden beds.
Create walkways around the yard to access them more easily after heavy rain.
Use it around your yard to prevent erosion and achieve a more rustic look.
If it’s too degraded, diseased, or pest-ridden, dispose of it.
DIY vs. professional mulch replacement
If you like hands-on projects and have the time, replacing mulch yourself can be a cost-friendly option. Just make sure you know what you’re doing and have the right tools. On the other hand, hiring a gardening professional can save you time and ensure the job is done right, especially if you have a large yard or intricate landscaping. They can also recommend the best mulch types and maintenance tips for your garden.
Beyond mulching, Lawn Love can match you with a local lawn care expert who can mow, aerate, overseed, and fertilize your lawn to keep it looking beautiful all year long.
Sources:
“How Much Compost, Soil or Mulch?” The Texas A&M AgriLife Extension – Extension Education in Travis County.
“Wood chip mulch: Landscape boon or bane?” By Linda Chalker-Scott, Ph.D., Extension Horticulturist and Associate Professor. Puyallup Research and Extension Center, Washington State University.
“Mulch plays important role in gardening.” The Oklahoma State University Extension – Division of Agricultural Sciences and Natural Resources.
“Using wood chips for mulch. Yard care and the environment.” By Robert Neier, Sedgwick County Extension Agent, Horticulture; Ward Upham, Extension Associate, Consumer Horticulture. Kansas State University Agricultural Experiment Station and Cooperative Extension Service.
“Using Mulch in the Garden.” By Aaron Steil, consumer horticulture extension specialist. Iowa State University Extension and Outreach.
Main Photo Credit: Ozgur Coskun / Adobe Stock
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