Plan the perfect garden with our interactive tool →

How to Grow Grass Over a Septic Tank

Grow grass over a septic tank by properly sowing the grass seeds and creating future environmental conditions favorable to the growth of grass. Lawn grass species prefer moist, high pH soil, and direct sunlight. Growing grass over a septic tank can be challenging due to the acidic, low-pH soil resulting from sewage runoff into the leach field.

Rake the septic tank area clear of rocks and organic debris using a flexible, metal rake.

Sow the grass seeds over the lawn by evenly distributing the seeds with a spreader. Use 2 or 4 lb. of seed when reseeding a mature lawn or over-seeding a new lawn, respectively.

  • Grow grass over a septic tank by properly sowing the grass seeds and creating future environmental conditions favorable to the growth of grass.

Sprinkle a 1/12-inch layer of lawn lime over the seeds using a spreader. Lime increases the topsoil's pH balance over time.

Cover the seeds and lime with a 1/2-inch layer of clean compost or peat moss fertilizer. Fertilizer moderates temperature fluctuations, increases moisture absorbency, and adds vital minerals and nutrients.

Water the newly planted seeds once daily for 2 weeks or until new grass growth is visible through the fertilizer.

Trim back adjacent flora to increase direct sunlight on the lawn area using outdoor trimmers.

Dead Grass Over My Septic Tank?

Oddly enough, dead grass over your septic tank is a good sign! It means your septic system is probably working the way it’s supposed to. However, the worst thing you can do is to water the brown grass. Even though the grass turns brown because there’s not enough soil to support its root system, you shouldn’t add topsoil over your tank, either. The trenches in your leach field are filling with liquid waste because the soil can’t absorb any more water from your house. Other signs of trouble include slow-draining toilets, sewage odors, and sewage backing up into the house or surfacing on the leach field. Select plants that don’t need much maintenance, watering or fertilizer.

  • Sprinkle a 1/12-inch layer of lawn lime over the seeds using a spreader.
  • Even though the grass turns brown because there’s not enough soil to support its root system, you shouldn’t add topsoil over your tank, either.
Garden Guides
×