Often when beginning a new landscape project contractors

will bring in topsoil for plants and turf. 

This is not always the best approach. 

Your soil health and composition are the most important consideration

for a healthy garden.  Site conditions

where it may be appropriate to bring in top soil include: sites with rocky soil

and/or high clay content.  In these

conditions existing soil should be excavated twelve inches down from finish

grade and replaced with good loamy soil rich in organic material. 

If the existing soil is sandy or light clay and low in

organic material a better approach is to add four to six inches of compost and till

it into the existing soil. 

A common issue in landscape areas is compacted soil.  Often this is due to heavy machinery used

during construction.  An important first

step in preparing your landscape areas is to disturb existing soil to a minimum

depth of 8 to 12 inches.  The best tool

for this is an excavator or mini excavator. At this step you can create your

drainage patterns and land forms such as berms and depressions. Once the soil

has been loosened and rough graded you can spread compost, till and re-grade. At

this point trenching can be done for irrigation, any conduit, or sleeves.

Blended soil should be graded such that planter beds finish

grade is 4 inches below all hard edges i.e. sidewalks or edges of turf areas. This

gives you room to add top dressing 3 to 4 inches deep all the way to the edge and

allows water to drain off of hard surfaces. Turf areas should be graded 2

inches below hard edges such as walkways, driveways and hard edges separating beds

from turf.