Clay Soil

Flooded clay soil garden area

Planting on Clay Soils


Here are a few tips to remember when planting on clay soil.
  • Don’t expect water to infiltrate well in heavy clay soils.
  • If you are unable to amend the soil, consider making the garden wider and shallower than recommended to increase the surface area for water infiltration.
  • Follow the soil amendments guide at right to remove clay soil and improve infiltration.
  • Dig the site and add compost to the soil. This will allow plants a habitat rich in nutrients and maximum capacity to soak up the rain and snow melt.

Adding Fresh Soil


When adding fresh soil, consider the following mixture:
  • 50- 60% sand and gravel,
  • 20-30% topsoil (no clay) and
  • 10-20% compost and mulch

The clay-based rain garden at Superior Middle School (pictured above) was a swimming pool until we back-filled it with rocks, sand, peat, mulch, and compost. It still drains slowly, but doesn't fill up with rainwater as quickly as it did when it was first dug.