As a foundation for many landscapes, mulch covers flower beds, vegetable gardens, and even playgrounds. Many plots require a three-inch layer of mulch for every square foot of area, but different factors call for different arrangements. An evaluation of your plants or your garden’s geography might reveal that one type of mulch will serve you much better than another. This blog will illustrate how to calculate the right amount of mulch that’s best for your plants.
What Is Mulch, and Why Is It So Critical?
Mulch is nothing beyond a layer of wood, compost or inorganic materials that serves as a foundation on which plants can thrive. There’s not much to it, but great mulch protects, nourishes, hydrates and aesthetically complements plants. For skillful landscapers, laying mulch is the first step, and to make that first step, you need to know how much you need.
How Deep Should Mulch Be?
Two-inch layers look pretty slick, favoring aesthetic over other factors. Because they’re so dense, fine mulch layers should generally be the thinnest so as not to block nutrients, oxygen and moisture from the soil.
Four-inch layers optimize protection, but they can potentially trap enough moisture to drown plants. Only the coarsest mulch with the most space among chips should fill four-inch layers.
Three-inch layers are a happy medium no matter what mulch you use, as they’re thick enough to protect plants and dense enough to feed the soil through decomposition. The bottom line is that too much mulch is as harmful as too little mulch, and a three-inch layer is the most effective way to avoid both extremes.
How Can I Calculate How Much Mulch I Need?
Once you decide how deep your plots should be, you can move onto their other dimensions. We anticipate that most of your plots will be rectangular, but we’ll show you how to calculate area for other types of shapes as well as how to approach more amorphous arrangements.
To find the area of a rectangle, multiply length by width. To find the area of a triangle, multiply a side by its distance from the opposite point, and divide the product by two. For circles, multiply the square of the radius by pi (3.14). Finally, ellipses aren’t much different from circles: Instead of finding the square of the radius, multiply the longest radius by the shortest radius before multiplying by pi.
If your garden features anything more avant-garde than an ellipse, don’t panic (though that’s certainly an option). Simply break the complex shape into imaginary rectangles, and overestimate accordingly. While a layer of mulch should never be too thick, having more mulch is better than having too little because you’re going to add more eventually. The more rectangles into which you divide complex plots, the better your estimate will be.
Once you find the area of your plots, you’ll need the total volume to find out how much mulch you need per square foot. You can figure out how much mulch you need with our calculator! All it needs to make calculations across different units is for you to provide the area and target depth. We’ll provide an answer in cubic yards.
Which Mulch Is Best for Me?
The right quantity of mulch isn’t going to go far if you use the wrong one. Depending on your plants or the immediate topography of your plots, certain mulches might serve your needs better than others. Here’s a breakdown of use cases for the fundamental flavors of mulch.
Hardwood Offers Most Nutrients
Hardwood is the best place to start. Its high density maximizes protection and provides the most nutrients to plants. The only issue is that hardwood increases soil alkalinity, and some plants, like tomatoes, favor acidity. Plots for aesthetic plants like shrubs and flowers benefit the most from hardwood mulch because most of them don’t thrive in acidic environments anyway.
If you have tomato plants, you might benefit from pine mulch, which makes soil more acidic. We don’t recommend pine mulch for aesthetic plots because, in combination with moisture, acidic soil invites fungus. It’s not the worst thing, but it doesn’t look nice.
If your garden is full of slopes, you might benefit from shredded mulch, as it’s much less likely than thicker chips or nuggets to run off in rain. However, shredded mulch can fly away in storms, so if you live in a windy area, shoot for whole tree chips or bark.
Whatever mulch you prefer, stay away from the cheapest bags you can find at the hardware store, as these are ordinarily full of chemicals that sterilize soil at best and destroy plants at worst. Walnut wood contains chemicals that inhibit plant growth, and straw mulch can contain lots of weed seeds, so be vigilant.
Black Makes for Contrast, while Red Suits Mild Palettes
Black, red and no dye are the most common, but we also provide brown and gold mulch. Black invites contrast into the scene, brightening the colors of your home and plants. Red is especially photogenic, complementing a mild color palette and making green plants pop. Dye-free mulch works for most plots, offering protection from weeds with little to no impact on appearance.
As for our brown and gold mulch, brown mulch has even less of an impact on plants’ appearance, blending into the background and filling soil with essential nutrients. Finally, our gold mulch is a vibrant accompaniment to the brightest flowers, and it’s great for retaining moisture.
Should I Purchase by Bags or Cubic Yards?
A cubic yard of mulch is less expensive than the same amount of mulch in bags, but how much mulch does a yard cover, and how many yards of mulch do you need? The more mulch you need, the bigger a difference favoring cubic yards over individual bags will make. There’s not much of a reason to buy bags of mulch unless your plots are especially shallow and small. Even then, a full bag can be anywhere from 20 to 50 pounds to carry. At best, bags of mulch potentially allow for easier distribution. They offer a bit of flexibility by being easy to store and use over time, but purchasing mulch by the cubic yard is almost always a superior option.
When Should I Replace Mulch?
Most residents ought to replace mulch annually. Remember not to remove preexisting mulch, as you need it to nurture your plants through further decomposition. For coarse mulch, you might be able to get away with waiting for two years, but pine mulch’s quick decomposition will require reinforcement every couple of months.
Where Can I Buy What I Need?
We’re glad you asked because you can buy 100% organic hardwood mulch straight from our yard in Rochester, MN. Our color palette is more expansive than that of other vendors, and we commit uncompromisingly to hardwood that’s entirely free from pests, mold and fungus. If you live within 40 miles of Rochester, we’d be happy to swing by with a mulch delivery this spring. For more information, please check out our other blogs, call us at 507-280-7780, or contact us here.