Preparing a Small Lawn Area with Amended Topsoil Over Clay

Preparing a Small Lawn Area with Amended Topsoil Over Clay

For a 12×20 ft area 4″ below patio level with irrigation tubes underneath:

Procedure

1. Remove 3″ of existing clay (careful of tubes).
2. Bring in 6″ of amended topsoil: sandy loam or 75% sandy loam / 25% compost.
3. Mix the 3″ clay with the 6″ new soil lightly at the interface.
4. Total amended depth: 9″—excellent for grass.
5. Volume needed: ~4–4.5 cubic yards.

Critical Check: Drainage

After grading, test by watering. If water ponds, you may need to excavate deeper and install a drain line before adding topsoil.

Sod can be laid anytime during growing season if kept moist until rooted.