You will have fewer problems with pests gardening in raised garden beds. If you have had previous problems with burrowing rodents, a lining of chicken wire in the bottom of each will eliminate them. Weed control is much easier handle because you can walk around a raised bed without having to bend over to pull out, if you have any weeds at all.
Number of anchors per board: (Usable Length / Spacing for anchors) - 1. For my beds, I need 7 separators for each 8 foot board and 3 for each 4 foot board.
Raised beds lend themselves to the development of complex agriculture systems that utilize many of the principles and methods of permaculture. They can be used effectively to control erosion and recycle and conserve water and nutrients by building them along contour lines on slopes.
Total number of anchors: Add the results of Step 2, and multiply by 2. In my example, (7+3) * 2 = 20 anchors.