I first got this idea from a older couple i know. I just wanted it bigger. My ground has a lot of clay in it so i built up my first garden about 10 inches off the ground.My parents are getting older so i thought i would make them a smaller one so they wouldn't have to bend over a lot . It sure is nice for weeding not having to bend over.Also you don't have to worry about getting a lot of rain at once because it will drain out the bottom rather than flooding your plants.
Step 1: Cad drawing
This is a cad drawing of the garden i am making.
Step 2: Legs and outside frame
I used (2) 2x8x12
(4) 3 inch lags screws for each leg and made the 8x12 frame.
Step 3: Installing the Joists
I screwed and nailed (8) 2x8x8 16inch on center joists.
Step 4: Finished 4x4 legs
I cut 10 4x4 legs 36 inches long. Here i finished installing the rest of the support legs.
Step 5: Bed frame
I screwed 14 1x6 deck boards to make the floor of the garden.
Step 6: Bed preparation.
I then installed (2) 2x6x8 and (2) 2x8x12 to the inside of the 4x4 s for the above ground outside frame. Since i used pressure treated for the floor and sides i needed a barrier to separate the soil with the treated wood . So i double up 2 layers of 8mm plastic sheeting as my barrier between the soil and wood.
Step 7: Drainage holes
I purposely left a 3/4 of a inch gap between each deck board for drainage. I drilled 1/4 holes through the plastic every 4 inches.
Step 8: Filler up!
I bought (50) 1 cubic foot bags of topsoil to fill the box.