When preparing the area for a new lawn, I had about 5 bags of topsoil left over. Can I take these up to the cottage and add them into my very sandy soil up there?
Certainly. However, if you want to improve your sandy soil further, you need to add organic matter, i.e. compost, not just the topsoil. The compost will add nutrients; increases the soil’s ability to hold water and nutrients; and create a better environment for beneficial microorganisms.