Low Fertility Topsoil
It's not so much that wildflowers don't like fertile soil, it's that if the growing medium you have is too rich they will be out-competed by more bullying species like some grasses, dock and nettle.
On new sites you can invert the topsoil wiht subsoil, for example, but using this low fertility topsoil is a simpler solution. It has been formulated with wildflowers in mind, so they will have all the nutrients they need.
We're able to deliver bulk loads all round the country, and generally use dumpy bags for smaller orders. Haulage is obviously a significant element of the cost, so we quote on an individual basis. Please ask for a price for your project.