Unless you are a landscaping professional constantly using mulch, knowing how much to purchase and how much it weighs can seem like a daunting task. Depending on the type, different mulches have differing weights and the amount of area a bag will cover.
Estimating Your Mulch Needs
If you install mulch for any length of time, you get to where you can easily estimate how much is required without any calculations. However, if you are only installing mulch occasionally, calculating your needs through eyeballing the area isn't quite as easy. Fortunately, online mulch calculators help determine the amount needed after you determine the square feet of the area if you don't want to manually figure out how much mulch you need.
To find the square footage you need to cover in mulch:
- Measure the length and width of the area requiring mulch.
- Multiply the two figures together.
- The resulting figure is the area's square feet.
For example, if your garden area is 12 feet long and 6 feet wide, multiply 12 x 6 and you end up with 72 square feet. Weight and coverage of various mulches will help you determine how many mulch bags to purchase.
Weight and Coverage of Organic Mulches
Organic mulches are generally less expensive than inorganic types and one bag covers a larger area than stone mulches. The product also weighs less and is easier to work with. However, there is a need to replace the product on a regular basis.
All types of organic wood mulches cover the same approximate area, depending on the installed thickness, though the weight of each bag is dependent on whether the mulch is wet or dry. The average weight of a bag of dry shredded wood mulch is approximately 20 pounds, which can almost double in weight when saturated with water.
Wood mulches come in 2 cubic foot bags. For the mulch to work properly in the suppression of weeds and moisture retention, it's recommended to install at a thickness of 2 to 4 inches.
- One bag installed at 2 inch thickness covers 12 square feet.
- One bag installed at 4 inch thickness covers 6 square feet.
Organic wood mulches come in various colors and types, with some treated with insecticides to repel insects such as termites. Some common types include various shredded hardwoods, shredded eucalyptus, and pine bark nuggets.
Straw is another organic mulch used for the germination of seeds such as grass. Straw mulch is generally found in bags containing 2.5 cubic feet and 1 cubic feet of the product. Apply straw mulch at a depth of around 1-inch so sunlight still reaches the seeds so it germinates properly. Applying too deep can prevent or reduce germination rates.
- A 2.5 cubic feet bag of straw mulch covers approximately 500 square feet and weighs around 50 pounds.
- A 1 cubic feet bag of straw mulch covers approximately 200 square feet and weighs around 20 pounds.
Compost is a another organic mulch. Simply spread it evenly on top of the targeted area. Compost generally comes in 1- and 2-cubic foot bags that weigh approximately 44 pounds per cubic foot.
- A 1 cubic foot bag of compost covers 12 square feet applied at a thickness of 1 inch and 6 square feet applied at a thickness of 2 inches.
- A 2 cubic foot bag of compost covers 24 square feet applied at a thickness of 1 inch and 12 square feet applied at a thickness of 2 inches.
Weight and Coverage of Inorganic Mulches
Inorganic mulches, such as rubber products, cover a smaller area per bag and can be more labor intensive to install even though care should be taken not to put it down too thick. On the upside, stone and rubber mulch is long-lasting and doesn't require the frequent replacing like wood mulch products.
All types of stones are heavier to work with than wood mulches with some slightly heavier than others. Shredded plastic mulches weigh somewhere between wood and stone mulches.
- River rock: A 0.5 cubic foot bag covers 2 square feet applied at a thickness of 2 inches and weighs approximately 50 pounds.
- Lava rock: A 0.5 cubic foot bag covers 3 square feet applied at a thickness of 2 inches and weighs approximately 18 pounds.
- Marble chips: A 0.5 cubic foot bag covers 2 square feet applied at a thickness of 2 inches and weighs approximately 45 pounds.
- Egg rock: A 0.5 cubic foot bag covers 3-square feet applied at a thickness of 2 inches and weighs approximately 45 pounds.
- Shredded rubber mulch: One 0.8 cubic foot bag covers 4.8 square feet applied at a thickness of 2 inches and weighs approximately 35 pounds.
Basic Mulch Installation Tips
Before installing any type of mulch in a walkway or garden bed, it's best to get rid of any unwanted weed or grass growth. This is as simple as spraying the targeted area with weed killer and allowing the vegetation to die, which can take a week.
If using wood, straw or compost mulches, you can apply the product directly to the ground, spreading it evenly over the area. When using dyed mulches, it's best to wear garden gloves because the color can stain your hands. To reduce the possibility of disease and pest problems affecting plants, always keep the mulch several inches away from trunks and the base of plants. Most wood-type mulches require refreshing about every six to 12 months.
Installing stone or rubber mulch involves an additional step to keep the product from sinking into the soil. It is best to install weed cloth over the area first so it supports the mulch and then lay the stone or rubber mulch on top. Otherwise, you will need to replace the product more frequently than necessary, which leads to a bigger expense. Keep your hands cut and scratch-free by wearing gloves when installing stone mulch. Keep the stone's thickness to approximately 2 inches, as applying too deep can impede the growth of plants and water from reaching the root systems.
Mulched and Happy
Not only will your plants be happy and garden beds look more appealing with a layer of mulch, but you'll be happier too. Mulched beds allow more time to relax and enjoy the scenic beauty of the garden and not spending so much time digging in the dirt pulling weeds and grass.