Do you have old window blinds you don’t need anymore? Are you planting a garden too? Then don’t throw out those unwanted blinds.
If you disassemble the horizontal portions of the window blinds, then place them in a grid pattern atop your garden bed, you have just created a perfect compartmentalization for your veggies.
You can see what it should look like in the example below. In this picture the drip line lays right on top of the the grid.
You can even write on (or adhere stickers to) the blinds to label your garden goodies.