Growing Square Watermelons for $8

Step 2 Cut the Keyhole, Drill Airholes

You will need to cut a large keyhole on one rectangle to allow the watermelon stem to poke through the box. Note the picture below. I use a hacksaw to cut the round part of my keyhole, but a holecutter bit would probably be easier.

Then drill 3 small (1/16" or so) airholes in each corner of each piece. That's 72 holes total. It's a lot of holes, but it is VERY important (prevents the watermelon from cooking in the sun, then rotting in the box).