#4 Stone vs Compost: Size, Cost, and Which to Use

#4 Stone

Sieve size #4 in the ASTM aggregate grading means most of the stone passes a 1.5-inch screen and stays on a 3/4-inch screen. In practice you get a pile of roughly walnut to golf ball sized rock. Every piece is angular because it was crushed, and those sharp edges lock together under load instead of rolling like river stone. Because it is washed or screened clean, there are no fines to fill the gaps between pieces. That is the whole point: about 35 to 40 percent of a pile of #4 is air, so water moves through it fast.

Compost

Decomposed organic matter used as a soil amendment to improve soil structure, fertility, and water retention. Quality compost is dark, crumbly, and earthy-smelling. It adds beneficial microorganisms and nutrients that support healthy plant growth and improve poor soils.

#4 Stone

• ✓ Driveway and road base
• ✓ Drainage beds
• ✓ Retaining wall backfill
• ✓ Construction entrance pads
• ✓ Pipe bedding for large pipe
• ✓ Erosion control

Compost

• ✓ Soil amendment
• ✓ Garden beds
• ✓ Lawn top-dressing
• ✓ Raised beds
• ✓ Tree and shrub planting
• ✓ Seed starting mix

#4 Stone

• + Excellent drainage with 35 to 40 percent void space
• + Bridges soft ground better than smaller stone
• + Cheap, $20 to $40 per ton, and stocked everywhere
• + Angular pieces lock together under load
• + Same price as #57 with more drainage capacity

• − Too coarse to walk on or drive on as a surface
• − Needs a finer cap layer for any traffic
• − Hard to rake and spread by hand
• − Sinks into soft clay without fabric

Compost

• + Dramatically improves soil structure and fertility
• + Increases water retention in sandy soils
• + Improves drainage in clay soils
• + Adds beneficial microorganisms
• + Reduces need for chemical fertilizers

• − Quality and composition vary widely between sources
• − Can be odorous when fresh
• − May contain weed seeds if not fully composted
• − Too rich for direct planting — must be mixed with soil
• − Settles significantly after application

#4 Stone

#4 stone is crushed rock screened to pieces between 1 and 1.5 inches, with some quarries running it up to 2 inches. It is angular with sharp fractured faces. Color follows the quarry: gray or blue-gray limestone in the Midwest and Northeast, gray to pink granite in the Southeast, tan limestone in Texas.

Compost

Fine, crumbly texture when fully decomposed. Dark brown to black color. Should smell earthy, not sour or ammonia-like. Screened compost has been filtered to remove large uncomposted pieces. Mushroom compost is a byproduct of mushroom farming and is particularly nutrient-rich.