Ordering too little mulch means a second trip or a second delivery charge. Ordering too much means a pile sitting in your driveway for two weeks. Getting the amount right starts with a simple calculation, and once you know how to do it, estimating any project takes about two minutes.

This guide walks through the math and gives you real examples based on common yard and garden projects in Southern Maine.

The Basic Formula

Cubic Yards = (Length × Width × Depth) ÷ 324

Length and width in feet, depth in inches

That is the calculation. Length times width gives you square footage. Multiplying by depth (in inches) and dividing by 324 converts to cubic yards, the unit we sell by.

Example:

A flower bed that is 20 feet long by 4 feet wide, mulched to 3 inches deep:

20 × 4 × 3 = 240 → 240 ÷ 324 = 0.74 cubic yards

Round up to 1 cubic yard for that bed. Simple.

How Deep Should You Apply Mulch?

This is the most common question we get, and the answer depends on what you are doing.

New Beds or Heavy Weed Pressure

Apply 3 to 4 inches for new planting beds or areas where weed suppression is the main goal. Deeper coverage blocks more light and slows weed germination more effectively.

Top-Dressing Existing Mulch

If you are refreshing mulch that already has an inch or two in place, a 1 to 2 inch top-dress is usually enough to restore appearance and function. No need to go back to full depth each year.

Around Trees and Shrubs

Keep mulch 2 to 3 inches deep in the surrounding area, but stay 2 to 4 inches away from the trunk itself. Mulch piled against tree trunks holds moisture and can cause rot and pest problems over time.

Common Project Examples

Garden Bed (20 × 6 ft, 3" deep)

~1.1 cubic yards, order 1.5

Front Foundation (40 × 3 ft, 3" deep)

~1.1 cubic yards

Large Area (50 × 20 ft, 2" deep)

~6.2 cubic yards

Full Property (10,000 sq ft, 1" top-dress)

~30.9 cubic yards, delivery order

Use Our Yard Calculator

The Beaulieu Logging bark mulch page has a built-in calculator where you can enter your dimensions and get an instant estimate. It handles the math so you can focus on planning your project.

Use the Bark Mulch Calculator

When in Doubt, Call Us

If your project involves unusual shapes, slopes, or multiple separate areas, the math can get complicated. Call us at (207) 590-7621 and we will help you work through the estimate. We would rather you order the right amount the first time than be short on delivery day.

How Much Mulch Do I Need? A Simple Guide for Southern Maine Homeowners