Well just so you know. What we ended up doing is doing soil tests on the berm/ fill material. We added lime and phosphorous according to the recommendations from the soil test. Which was about $50 worth of materials. Not much money for being all scientific about it. Then we brought in 50 cu yds of a compost / landscaping mix I found around raliegh, NC. Finedge you might be interested in that stuff found at
www.mcgill-leprechaun.com. We layed that on top about 8 inches. We didnt mix it in because this will then give them the black stuff they desire and give us a bed for any perennials.