Raised planter beds
When I was a kid I learned how to build raised planter beds from a family friend. I ended up building quite a few, first in my family’s yard then for friends’ parents. It made me a nice bit of cash.
The process is incredibly simple. All you need are a few 2x4s and some 2x6s. The 2x4s act as the vertical corner pieces and 2x6s get stacked horizontally and drilled into the 2x4s at the corners. Here’s the bed I built for our current garden:
There’s really not much too it beyond that; make a few cuts and drill together the pieces. If you want it to last a while you can line the inside with black plastic or use redwood, but I don’t really anticipate this one being around too long.
You don’t even need a planter bed, though. I’ve had success planting directly in the ground.