Soil testing is performed on nearly every project prepared by this office. Usually,
the samples are collected before new work has occurred and therefore they may not
reflect actual conditions at the time of planting. For this reason, the drawings
(Specification Section 02920, Part 3.1) often call for a new soil test to be performed
by the landscape contractor after rough grading or prior to importing planting soil.
Soil tests on the drawings are provided to meet agency requirements and are not acceptable
as a substitute for mandatory pre-planting testing.
Sunland Analytical Lab’s LTP3 landscape soil testing is adequate for most situations,
although LTP4 may be a better choice if no testing has occurred in the past 2 years.
An order form is provided here and sampling instructions follow:
Clean testing tools and containers prior to collecting samples.
Perform one soils test for each acre of gross project area or one for each different
soil condition on the site, whichever quantity is greater.
Take a minimum of 10 different samples (1/4 cup each) for each soils test required
at multiple depths ranging from 1 inch to 12 inches. Thoroughly mix samples.
Nearly every landscape renovation project this office has undertaken begins with
a soil test. Invariably, the results indicate a massive deficit of nitrogen, which
accounts for the yellow foliage and stunted growth that is typical of minimally maintained
Annual soil testing, possibly by an individual who is not an employee of the landscape
maintenance company, may be the most important factor in restoring older plants to
a healthy appearance.