How to Establish an Area with Forest Floor Mat or Sod

A good final result for both forest floor mat and sod requires that the ground is properly prepared. Below are instructions for preparing the ground and installing both materials.

FOREST FLOOR MAT

Under the forest floor mat there must be at least a 10 cm layer of sand that contains no grass or other perennial weeds. Soil or clay are not suitable beneath forest floor mat. If the installation site is an old forest floor, the original base may in the best case be suitable as it is. Otherwise, follow these instructions:
If the forest floor mat is installed in an area where grass or other perennial plants are growing, you must either:

• Remove the topsoil containing the roots of perennial plants and spread sand afterwards, or
• Place a root barrier fabric over the existing vegetation and spread sand on top of it.

The sand base for forest floor mat should be spread in an even layer of 10–15 cm. The sand must be fine enough to retain moisture. Natural sand is the best base material.
Stone dust is not the best base because it may compact and become very hard. However, it can work well on slopes.

If the forest floor mat area is on a steep slope, it may be necessary to install transverse retaining boards to prevent the sand from sliding downhill.
The sand should be leveled but not compacted. The edges of the sand area should be sloped, so that there is no height difference between the forest floor mat area and the surrounding ground.

The forest floor mat is installed so that the edges of the mat pieces meet tightly. There must be no gaps and no overlapping pieces. The forest floor mat must be watered during the first summer.

SOD (Roll Turf)

Under the sod there must be a 20 cm compacted layer of soil. The soil should be spread as a 25 cm layer, which will settle to about 20 cm when compacted.

Before spreading the soil, make sure that the ground does not contain roots of grass, dandelions, or other perennial plants.

The soil should be spread as an even layer. If necessary, the leveling should be finished by hand.

The soil is compacted either with machinery or with a hand-pushed water-filled lawn roller. The soil must be thoroughly watered before installing the sod.

The sod should be installed in a staggered pattern (brick pattern). After installation, the lawn should be watered for 2–3 weeks, ensuring that the sod rolls remain moist all the way to the base layer.

The lawn can be mowed once the grass reaches a height of 4–5 cm.