Build a Raised Bed

If you wanted, you could absolutely plant right into the soil (after amending of course) but I find in the suburban atmosphere, having a raised bed is more attractive. There are many ways to construct a raised bed, this is just one of them.

Materials

• 6 landscape timbers (these are fatter than a 2x4 with two flat sides and two rounded sides. they are 8' in length and are usually pressure treated pine - meaning they have a yellowy-green tint and are usually damp feeling) Make sure you look down the long side of each timber to make sure it is pretty straight. If there is any curvature now, it'll only warp more when it dries out in the sun.
• 10 18" cuts of 1/2" rebar (you should be able to find these pre-cut, but you're welcome to cut your own)
• 3/4" wide 12 inch long drill bit, kinda like this
• Corded drill
• Hammer
• Radial Arm Saw or Table Saw or Rotary Hand saw

Directions

Cut two of the landscape timbers in half with the saw (4 ft lengths). Assemble the timbers on the ground where you want the bed to sit. Each wall should be two timbers high. Stagger the corners so that the timbers interlock

Have a helper hold the timbers together so they do not shift while drilling. Drill 3 evenly-ish spaced holes across each 8 ft side and two holes in each 4 ft side. Use one fluid drilling motion to go all the way to the soil and back out between both layers of timber. Hammer in a rebar into each hole almost flush with the top timber and you're done! The rebar won't be tight against the timbers and that is just fine, it'll hold up just fine and the space will eventually fill up with dirt for more support.

Helpful hint: drill the center hole on the 8 ft side first, hammer in a rebar then drill the end holes. This will minimize shifting. Hammer each rebar in as you make the holes instead of drilling all the holes first. You can do the assembly by yourself but I make the DH do the drilling and I assist and hammer in the rebar.

This method is simple and while the timbers are more expensive than regular treated lumber, you won't have any bowing or bulging issues. If you want to add in weed barrier along the walls of the bed now is the time to do it. I didn't bother, the St Augustine grass occasionally tries to creep into the boxes but not often enough that it bothers me. If you want deeper boxes, just add another layer of timbers. You may need 2' rebar if you choose to do that and it may be trickier to drill through three layers at once. I find 2 layers sufficient.