i have some questions on preparing soil...in maine most of the soil is very acidic due to pine tree needles and shit like that. and usually the topsoil is very mulchy and rich..but about 5-6 inches in the ground you will find clay in most spots. i would figure clay has very poor drainage. and i know sand has very good drainage. i dont want to disturb the soil to much. so would it be effective at all to increase my drainage by adding sand over the top of my plot instead of disturbeing my soil? or should I mix it in with the loose soil after transplanting my plants to the ground, and use the sandy soil to fill in the plant holes?