Calculate how much mulch you need for your garden bed!
Planning a garden project? Use our handy mulch calculator to quickly estimate how much mulch you’ll need, based on area size and depth, as well as different types of mulch. Skip the guesswork!
Mulch is a gardener’s best friend. It's a layer of organic material spread over soil to retain moisture, suppress weeds, and regulate temperature.
Applying mulch also helps improve plant growth, reduce water usage, and cut back on weeding time. Whether you're refreshing garden beds or starting from scratch, mulch is a simple, effective way to protect and beautify your outdoor space!
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The best mulch is any natural mulch that is plant-sourced. Shredded bark nicely decomposes over time, enriching soil health. Pine needles or pine "straw" are popular in the south and are natural-looking. We tend to use the bigger wood chips for paths, not gardens, as they don't decompose as well. Straw works well, as long as it’s weed-free. Of course, mulched leaves are the best—and free!
In a food garden, just ensure mulch material is not "colored" or chemically sprayed with herbicide or pesticides. Do not ever use rubber mulch in food gardens.
Learn more about the different types of mulch here
How Do I Measure for the Mulch Calculator?
You’ll need to know the length and width of your garden bed. If you have multiple spaces, there is a tool to add them up! If it’s a wonky shape, break it into smaller rectangles and add ’em up.
For example in the image below, you can see that
- One section is 5 feet by 12 feet
- The other is 8 feet by 6 feet
- These rectangles cover the whole bed—even the curves! This gives you a good estimate.
Now just enter each section into the calculator, and our Mulch Calculator will figure out how many bags or cubic yards you'll need based on your desired mulch depth.
How Deep Should My Mulch Be?
The ideal mulch depth depends on where and why you're mulching.
Here’s a quick guide:
| Area | Depth | Mulch Type & Guidance |
|---|---|---|
| New Raised Vegetable Beds | 3 to 4 inches | Use a thicker layer for new beds to suppress weeds and retain moisture. Choose fine, weed-free mulch like straw, shredded leaves, or composted bark. |
| Established Vegetable Beds | 1 to 2 inches | Ideal for topping up existing mulch. Avoid smothering seedlings and keep mulch slightly back from plant bases. |
| Flower Beds & General Landscaping | 2 to 3 inches | Helps retain moisture and block weeds. Use bark mulch, wood chips, or pine straw. Keep mulch away from tree trunks and shrub stems. |
| Pathways, Walkways, or Decorative Areas | 3 to 4 inches | Thicker layer helps hold mulch in place. Coarser materials like wood chips work best for these areas. |
How Much Mulch Do I Need?
That depends on how big your space is and how deep you want the mulch. Our calculator takes care of the math—just plug in your numbers.
How Many Bags of Mulch Do I Need?
Most mulch bags contain 2 cubic feet of material so this is what our calculator uses. But if your bags are larger, divide your total cubic feet needed by the bag size to determine how many to buy.
Catherine Boeckmann
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