Sheet Mulch Specification

Sample Sheet Mulching Specification for Lawn Conversion

  1. Site preparation:

    1. Shut off irrigation and cap off existing sprinkler heads.  
    2. Remove 12- inch wide strip of lawn adjacent to all curbs, hardscapes, drains, and other elements such as valve boxes and vaults.
    3. Flip turf roots side up toward center of the lawn to be sheet mulched.  Pile excavated sod to create a mound or keep as a single layer. 
    4. Grade soil surface to a depth of 4-6 inches below top of hardscape, drain, vault or other element to allow adequate room for sheet mulch profile.  Taper the cut back at a shallow angle (less than 45 degrees) to meet existing grade at existing turf to remain in place.
    5. Install 5-gallon and larger plant material so that top of root ball will be even with top of sheet mulch.
  2. Sheet mulch installation

    1. Install a minimum of two layers of 100% recycled B-flute cardboard to the entire planting area, completely covering all existing soil and remaining herbaceous vegetation, if any. 
    2. Wet cardboard while applying to prevent it from blowing away.  Keep all foot traffic off wet cardboard.
    3. Overlap cardboard a minimum of 12 inches.
    4. Cardboard shall abut directly against edge of pavement, curbs, boulders or other site features.  Do not cover tree and shrub root crowns with cardboard.
    5. Fold excess wet cardboard under itself when at hardscape or root crowns.
    6. Retain any small cardboard scraps to patch holes created during sheet mulch process.
    7. Apply 1 1/2 to 2 inches of quality OMRI- or CDFA- listed recycled organic compost on top of the cardboard layer.  Taper compost application to ½” when 6” or less from hardscape.
    8. Apply 3 inches of mulch on top of the compost.
    9. Keep stems and trunks of all plants clear of compost, mulch and debris.
  3. Planting

    1. One-gallon plants
      1. Push back compost and mulch to expose a circle of cardboard.
      2. Cut an "X" into cardboard and pull back flaps.
      3. Dig a shallow hole.
      4. Place plant in hole so that top of rootball is even with top of mulch after planting.
      5. Replace compost and mulch.
    2. Small plant material (4-inch pots, plugs, etc.).
      1. Push back compost and mulch to expose a circle of cardboard.
      2. Place plant on cardboard
      3. Replace compost and mulch
      4. Keep stems and trunks of all plants clear of compost, mulch and debris.
  4. Post-sheet mulch activities

    1. Conduct a site walk through to identify bare or low areas and exposed cardboard. 
    2. Add mulch to cover bare or low areas to a depth of 3 inches minimum.
    3. Fold exposed cardboard under at curb, trees, valve boxes and other edges.