[clkeiper]

You don't want the walls to be only 4' high if you are more than 4' tall yourself. the center should be at least 6' high. you will have to be bent over every time you go inside of it. you will want it at least a foot taller than you in the center. and 4 foot side walls are a waste of your structure if you put benches on the sides, it gives your plants no space to grow. even if you are planting in the ground you still need 6' sidewalls. most plants grow more than 4' tall