Types of mulch: Everything you need to know about mulch

person holding mulch in both hands

Choosing mulch to spread around your plants, trees, and garden beds? You have plenty of options, including grass clippings, compost, wood chips, straw, rubber pellets, and more. 

Mulch can be organic (formerly living but now decomposing materials) or inorganic (non-living natural or manmade materials), and range from nutrient-rich compost to sturdy fabric to decorative stone. 

Whether you’re seeking plant food or curb appeal, mulch has you (and your lawn) covered. 

In this guide, we’ll walk you through the different types of mulch (organic and inorganic — there are all sorts of varieties of each), the benefits of mulch, how to calculate how much you will need, how to apply mulch, when to apply mulch, and how to pick the perfect mulch for your yard. 

What is mulch?

wheelbarrow next to a large pile of mulch
Manfred Richter | Pixabay

Mulch is a material you spread throughout your landscape to prevent erosion, insulate soil, and retain soil moisture for healthy plant growth. Mulch protects your soil and strengthens tree roots, grass, and garden plants. Plus, the right mulch can give your lawn loads of aesthetic appeal. 

Mulch prices vary from free (shredded newspapers, grass clippings, etc.) to pricier for rubber mulch for your backyard playground or underneath your treehouse.

To choose the best mulch for your outdoor project, you have to first decide whether you want organic or inorganic mulch.

Organic vs. inorganic mulch

Organic mulch

Organic mulches are best for homeowners who want to give their lawn a long-lasting nutrient infusion, while inorganic mulches are best for preventing weeds and enhancing your yard’s appearance. 

Types of organic mulch include plant-based materials like wood, tree bark, cocoa bean hulls, pine needles, and leaves. 

Because organic mulches were once alive, they slowly decompose on your lawn over time. The decomposition of organic material gives your lawn the added benefit of nutrients and attracts soil superstars like earthworms and beneficial microbes. 

Inorganic mulch

plants in a flower bed with mulch surrounding them
peganum | Flickr | CC BY-SA 2.0

Inorganic mulches can be natural or synthetic but the materials were never alive, so they don’t decompose. This means you don’t have to replace them as frequently as organic mulches, but it also means they don’t return nutrients to the soil. 

Types of inorganic mulches include river rocks and gravel (which are natural) and landscape tarp, black plastic, and rubber pellets (which are synthetic). 

Not sure how to choose between organic or inorganic mulch? We’ll cover that below to help you make a decision. 

Benefits of mulch

pathway with stone stepping stones, red mulch and landscaping
Cldratler | Pixabay

Mulch offers a treasure trove of benefits, which is why landscapers, gardeners, and soil experts swear by mulch. 

Mulch, both inorganic and organic … 

  • Keeps soil moist, reducing evaporation so you won’t have to water as frequently. 
  • Prevents soil compaction, keeping grass green and lush and reducing your aeration needs. 
  • Keeps soil temperatures stable, which prevents frost heaving. Frost heaving (the repeated freezing and thawing process that pushes plants out of the ground and damages roots).
  • Prevents weed growth, so trees, shrubs, and flowers don’t have to compete with unwanted plants for nutrients.
  • Adds visual appeal: Mulch is a favorite decoration among landscapers and gardeners. It gives your yard texture and a pop of color. 
  • Increases root growth: Plant roots can extend into the mulch instead of being confined to the soil.
  • Prevents the spread of soil-borne diseases by reducing soil splash during rainstorms. Fungal and bacterial diseases from soil splash can cause leaf discoloration, wilting, and plant death. 
  • Protects trees and shrubs from mowing damage, so roots and bark stay healthy and intact. 
  • Reduces soil erosion from wind and rain, keeping the soil surface permeable and protecting your ecosystem from harmful runoff. 

How to apply mulch in 4 steps

To apply mulch, you likely will need a rake or some other tool to spread the organic or inorganic material, and if you have a lot of mulch (several bags or a truckload), you may need a wheelbarrow to transport it from your vehicle or driveway to where you plan to spread it.

You can apply mulch in four easy steps: 

1. Remove debris: Clear twigs, sticks, and rocks from the area where you plan to apply mulch. 

2. Weed the area: This prevents weeds from becoming embedded in your mulch as they grow.

3. Spread your mulch: Apply 1-4 inches of mulch over your desired mulching areas. Don’t apply more than 4 inches: Too much mulch can damage your plants and soil. 

4. Water the area (if your mulch is organic): Give the area 1 inch of water to set your mulch in place. 

How much mulch do you need?

Mulch is normally measured in cubic yards, and you can purchase mulch by the bag or the truckload — or maybe pick up free mulch if your local parks service shreds Christmas or other trees. 

The amount of mulch you need depends on the size of your area and how deep you want your layer of mulch to be. 

Calculate the volume of mulch you need by multiplying the area (in square feet) by your desired depth (in fractions of a foot). This gives you the amount of mulch you need in cubic feet. There are 27 cubic feet in a cubic yard, so to find how many cubic yards of mulch you need, divide by 27.

Let’s say you want to mulch a part of your yard with an area of 180 square feet, and you want your mulch to be 2 inches deep.

Convert your desired depth of 2 inches to feet. 

2 inches / 12 inches = 0.17 feet

You want your mulch to be 0.17 feet deep.

Multiply your area in square feet by your desired depth in feet to find the cubic feet of mulch needed. 

Area in sqaure feet x Desired depth in feet = Cubic feet of mulch needed
180 square feet x 0.17 square feet = 30.6 cubic feet of mulch needed

You’ll need 30.6 cubic feet of mulch to fill your area.

To convert between cubic feet and cubic yards, divide by 27.

Cubic feet of mulch needed / 27 cubic feet per cubic yard = Cubic yards of mulch needed
30.6 cubic feet of mulch / 27 cubic feet per cubic yard = 1.13 cubic yards

You’ll need 1.13 cubic yards of mulch. 

Here’s a quick and easy guide to decide approximately how many cubic yards of mulch you need:

Square footage2” mulch depth3” mulch depth4” mulch depth
200 square feet1 cubic yard2 cubic yards2.5 cubic yards
500 square feet3 cubic yards5 cubic yards6 cubic yards
1,000 square feet6 cubic yards9 cubic yards12 cubic yards
1,500 square feet9 cubic yards14 cubic yards19 cubic yards

When should you apply mulch? 

You can apply mulch at any time of the year, but it’s most beneficial to spread mulch in the middle of spring. Here’s why: Plants will thrive with a layer of fresh mulch as their roots warm up and begin their most vigorous growth period.

How to choose between organic and inorganic mulch 

Organic mulch or inorganic mulch? This can be a tough decision, but here are some pros and cons of organic and inorganic mulch to consider: 

Pros of organic mulch

✓ Increases soil quality and nutrient levels for lasting plant health.
✓ Improves soil structure and texture.
✓ Invites beneficial microorganisms and earthworms.
✓ Costs less than inorganic mulches.
✓ Stabilizes eroded areas.
✓ Won’t overheat your garden.

Cons of organic mulch

✗ Requires routine replacement.
✗ May contain weed seeds (especially grass clippings and straw mulch).
✗ Can deplete soil surface nitrogen levels.
✗ Moist wood mulches can attract pests like termites and roaches

Pros of inorganic mulch

✓ Long-lasting (does not decompose).
✓ Doesn’t include weed seeds.
✓ Doesn’t deplete nitrogen in soil.
✓ Eye-catching and versatile.
✓ Prevents pests.

Cons of inorganic mulch

✗ Stone mulches settle deep in your soil.
✗ Rock mulch absorbs and reflects heat.
✗ Plastic sheeting prevents the flow of air and water.
✗ Landscape fabric can suffocate worms.

How to pick the perfect mulch for your yard

From beautiful stones to nutrient-rich compost, mulch can be a feast for your eyes and your soil. If you’re feeling overwhelmed by this lawn buffet, asking these questions may help you choose the perfect mulch for your yard:

  • In your garden: Do you mind compost (with any residual smells) in your vegetable garden? Do you like the scent of a woodsy mulch spread in your flower beds or perennial garden?
  • Around trees: What color of mulch do you want around the base of your trees? What texture? Do you want to add nutrients to the soil around your trees?
  • Time and money: Do you have the hours and muscles to push around a wheelbarrow (maybe multiple trips) of mulch? How often are you willing to reapply mulch? If this is all just too mulch for you, would it be easier to hire a pro?

If you’d rather someone else help with the mulch decisions and placement, contact a local lawn care pro to guide you through which mulch type is right for you — and then handle all the dirty (or at least mulchy) work. Your lawn will get the premium mulch treatment, and you won’t have to lift a finger. 

Main Photo Credit: Dvortygirl | Wikimedia Commons | CC BY-SA 3.0

Maille Smith

Maille-Rose Smith is a freelance writer and actor based in New York. She graduated from the University of Virginia. She enjoys watching theatre, reading mysteries, and listening to psychology podcasts. She is an orchid enthusiast and always has a basil plant growing in her kitchen.