Question
was thinking about topping my white spruces they are approx. 20'tall
they are staggerd every 7',ten in each row,how will this affect there growth pattern? Also wanted to prune back only one side which faces my neighbors property,how would this effect growth on cut side?

Answer
Topping will either kill the trees or severely damage them. The growing part of the tree is the terminal stem and when this is cut the tree may never recover. It is not a good idea to top trees. Side pruning will not harm the tree but I would do this before spring to keep down the amount of sap flow from the wounds. If you are going to prune back the limbs make sure you leave plenty of foliage so the limb will survive If you just leave a bare branch the limb will die. You can cut the limb back to the trunk but the tree will have a lopsided look to it. The trees planted in off setting rows will not effect the growth pattern except that over time the limbs will intersect and from a hedge which sounds like what you had in mind.