Soil Amendments


Construction

Installation schedule considerations include not only grass seed germination but also other time constraints associated with actual on-site construction.  In scheduling and implementing soil amendments the following should be taken into consideration.

  • Turf germination period. Seed germination and subsequent turf establishment can take anywhere from nine to twelve weeks, depending upon the climatic zone. The critical window for seed germination is usually within the first 2 to 3 weeks and grass seed will germinate only if proper water, soil and air temperature considerations are met. Soil amending is discouraged immediately after turf establishment as well as during frozen soil conditions.

  • Site development schedule. As the building construction completion date is often the primary factor in determining the landscape installer’s schedule the implementation of soil amendments are limited to a particular timeframe, usually after building construction and driveway and sidewalk installation. Care should be taken to ensure that soil amendments are implemented during the right season and under the right conditions in relation to other landscaping activities and that the soil will not be adversely affected by the potential compaction of construction equipment after the amendment process.

Soil amendments can be implemented on existing developments, when replacing or modifying an existing lawn, and are usually not subject to limited time constraints, just the season and current weather conditions.  The recommended procedure is to first remove the lawn by use of a sod cutter and then amend the soil as if installing a new lawn at the site.  If stored correctly the lawn can be easily replaced after the soil has been amended.

The following is a summary of a typical sequence of construction for the installation of soil amendments. 

Southern Maryland Wood Treating Site: On-Site Thermal Desorption of Contaminated Soils, Excavation
Southern Maryland Wood Treating Site:
On-Site Thermal Desorption of Contaminated Soils,
Excavation
(Source: US EPA)

Step one:

  • Initial soil disturbance. This is usually performed with tractor, sometimes in combination with a ripper attachment if the soil is highly compacted.

Step two:

  • Uniformly break-up subsoil. Most soils will require at least two passes with a rototiller to adequately break-up and prepare the subsoil for amendment uptake.

Uniform mixing of compost using a rototiller
Uniform mixing of compost using a rototiller
(Source: US Composting Council)

Step three:

  • Rock removal. The removal of rocks on-site is performed as necessary – by hand, by rake, or by the use of mechanical equipment.

Step four:

  • Distribution of imported compost.

Step five:

  • Lime and Fertilizer application. The rates of these two soil amendments are determined by soil analysis; application is achieved along with compost distribution.

Step six:

  • Soil integration, Most soils will required at least 2-passes with a rototiller to adequately integrate and prepare the subsoil for amendment uptake.

Step seven:

  • Grading and rolling of site, The final aspect of the soil amending process prior to turf establishment is to achieve a uniformly smooth site surface.

 

Southern Maryland Wood Treating Site: On-Site Thermal Desorption of Contaminated Soils, Final Grading and LeafGro Placement
Southern Maryland Wood Treating Site:
On-Site Thermal Desorption of Contaminated Soils,
Final Grading and LeafGro Placement
(Source: US EPA)

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