Both pea gravel and river rock are naturally water-worn, smooth rounded stones that never decompose or attract termites like wood mulch. However, their size difference—3/8" pea pebbles versus 1" to 3" river cobbles—completely changes how they perform in your yard.
When to Choose 3/8" Washed Pea Gravel
- Barefoot & Paw Comfort: Smooth 3/8" pebbles feel comfortable under shoes, bare feet, and dog paws—making pea gravel the #1 choice for fire pit patios, courtyard seating areas, play spaces, and dog runs.
- Higher Coverage Per Ton: Because you only need a 2.5" to 3" depth, 1 cubic yard (1.28 tons) covers 108 to 130 square feet.
- Requirement: Always install rigid metal, stone, or poly edging around pea gravel beds so stones stay contained.
When to Choose 1"–3" or 3"–5" River Rock
- Leaf Blower Friendly: You can run a high-powered backpack leaf blower directly over 1"–3" river rock to clear autumn leaves and pine needles without blowing a single stone out of the bed.
- Erosion & Stormwater Control: Heavy river rock stays put in downspout splash zones, foundation drip lines, and dry creek drainage swales.
- Depth Rule: Because larger stones leave gaps that expose landscape fabric if spread too thin, 1"–3" river rock requires a minimum 3" to 4" depth (and 3"–5" cobble requires 5" to 6" depth).
Compare quantities side-by-side with our Pea Gravel Calculator and River Rock Coverage Calculator.