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Build a wood frame that is 3' on wood side and width of your door on the other. The 3' side will be the depth of your potting table. (modify it as you desire depending on how much work area you desire for your planting creations). The side that matches the width of your door will be the area that you mount the frame to the door. Your frame will be made with the 2x4's on their side, secured at the ends with 2 screws into each connection point.
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