Small Construction Footprint03/25/10Minimizing site damage to move landscape design beyond landscape repair.
August 19, 2010
Re-laying stockpiled soils
In May, following a dry spring, we were able to re-lay the stockpiled soil over the construction staging area. Prior to construction, the site was covered with a healthy stand of old hayfield grasses and wildflowers, along with their equally healthy and extensive root systems. We removed and stockpiled the soil without first rototilling it and found, come May, that the uncomposted sod (tops plus root clumps) made it impossible to spread the stockpiled soil out evenly over the areas being regraded. In fact, it was a lumpy, ankle twisting mess.
Wade Brown (Guy Hanson & Son Construction) and his brother James solved the problem by spreading the soddy soil out using the backhoe and then breaking it up with a large, tractor drawn rototiller. The result was fine-grained enough to allow us to spread it out and set the grades we wanted. After grading, we seeded different areas around the building with three custom mixes: a NE native wildflower and grass mix in the swale to the south side of the building; a NE native grass mix (with a few wildflowers) in the area over the septic field and a no-mow fescue turf mix for the areas immediately around the building.
Typically, when installing a seeded wildflower meadow or new field planting, the existing plant material is treated with an herbicide and removed (or tilled) prior to seeding to insure that the seed mix plants can be established as the dominant species. We didn’t want to use herbicides or other chemicals on the project and we also wanted to reuse stockpiled soils onsite, rather than taking them offsite to be screened or bringing in screened loam from somewhere else. The building construction timeframe was not long enough to be able to compost the organic material in the soil stockpiles.
Which meant that the tilled soil contained the ‘seed bank’ and the root systems (chopped up but still viable) of the pre-construction field. Which in turn means that plants from the pre-construction field will reappear everywhere we re-laid the stockpiled loam, resulting in a literal integration of the pre- and post- construction landscape. Instead of building a new landscape by clearing – emptying – the site of soils, plants and animals, the process of landscape design and construction becomes additive.