Soil Composition

A representative example from Houston (Harris County) shows soil made up of approximately: ~40% sand, ~30% silt, ~15–25% clay.

This blend is what defines loamy soil, which is generally good for plant growth because it balances: Drainage (from sand), Nutrient holding (from clay), Moisture retention (from silt). However, local conditions vary and zone 9b is known for having area of heavy clay. This requires local gardening and landscaping professionals to use a variety of organic matters to loosen clay rich environments.