When gardening in these beds only means you are growing your flowers and vegetables above the ground. You can create your own by building a wooden structure with drainage holes in the bottom and fill it with your favorite organic soil mixture. Concrete blocks, bricks, or just about any material strong enough to hold the garden bed and raise it above the ground can be used.
Numbering starts in the upper left corner and moves left to right, top to bottom. For example, planting square A1 is the upper left-hand square (1st column, 1st row), while planting square C4 is the square in the 3rd column and the 4th row. I have yet to find a commercially available garden bed with an included feature for marking off planting squares.
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.
Total number of anchors: Add the results of Step 2, and multiply by 2. In my example, (7+3) * 2 = 20 anchors.