If this is a really low cost grow and better soil isn't an option you could use things like straw, leaf compost, grasses, etc mixed in with the dirt to help soften it up. If things succeed, don't toss the dirt keep working it. It will get better.
Be very careful how much FoxFarm you add. It will hurt more than help. Use 1/4 or less what the directions are calling for. Working your way out of a nutrient lockout or salt build up is going to be hard in that dirt.