What is used for drainage in a post hole?

• A. 6 inches of gravel
• B. 4 inches of sand
• C. dig a drainage trench
• D. cement in the bottom

Answer: (A)

Water needs a path to escape the hole so the wooden post stays drier and less prone to rot. Filling the bottom of a post hole with gravel creates a porous layer that lets water drain away quickly instead of sitting against the wood. Six inches provides enough volume for effective drainage while still leaving room to set the post and backfill with soil.

Putting sand at the bottom would trap moisture and compact, reducing drainage. Digging a separate drainage trench is a larger-scale solution and isn’t what a single post hole uses. Cement at the bottom would seal the area and block drainage, which invites moisture problems.