Site Preparation for Wildflower Pollinator Gardens
Source: The Xerces Society for Invertebrate Conservation
The importance of site-preparation cannot be overstated. Before planting, you will need to eliminate existing undesirable vegetation, eradicate weeds, remove plant debris, and ensure you have a clean surface that will facilitate good seed to soil contact or be cleared for using transplants.
Tilling or cultivation should be avoided as part of any site-preparation strategy. Tilling kills ground nesting insects and brings weed seeds to the surface where they will germinate and negatively impact wildflower establishment. Additionally, repeated cultivation damages soil structure, speeds erosion, and releases carbon dioxide into the environment.
Manual removal is an option if you want to plant soon after you prep the site.
Tools need are a lawn edger and a sharp spade.
Work in sections: Divide your turf into squares with the edger, then lift with the spade.
Dig out any remaining weed roots with a trowel or shovel.
Your blocks of turf can be turned upside down, stacked and kept moist. They will rot and can be used as compost.
No need to amend the underlying soil.
Smothering and Solarizing
For gardens or smaller plantings (1000sf or less) smothering is an ideal, chemical free site preparation method. Prior to the active growing season, cover the area completely with cardboard or a heavy layer of newspaper - overlapping this material to ensure the entire area is covered. Then cover the material with compost, leaves, yard trimmings, or other material that will naturally break down. Allow the site to smother for an entire growing season before planting for best results.
Similar to smothering, solarizing is our preferred method of organic site preparation and has proven to be more than 90% effective at eradicating existing weeds. As with smothering, the entire area is covered in clear plastic prior to a growing season (this can be done in fall or winter where the ground is workable.) Edges of the plastic are buried to keep the plastic in place and to keep heat in. By trapping heat and limiting oxygen and room to grow, unwanted vegetation is smothered. This method is effective at killing annual, perennial, and biennial weed species without herbicides.