How to Build a Box to Sprout Seeds Early

Measure the inside length of the baking sheet with the tape measure and mark this dimension twice on the lumber with the pencil. Cut along the pencil lines with the circular saw to cut out two boards that will fit along the long edges of the baking sheet.

Place the two boards in the baking sheet, positioning them on a narrow end so they run along the long edges of the baking sheet.

Measure the distance between the two boards along the short edges of the baking sheet. Mark this dimension twice on the lumber with the pencil and cut along the lines with the circular saw to cut two more boards that will fit along the short edges of the baking sheet.

Sand the cut edges of the boards with the medium-grit sandpaper.

Hammer the tip of a nail through the bottom of the baking sheet to create drainage holes in the baking sheet. Make holes about 2 to 3 inches apart over the entire bottom surface of the baking sheet. Line the baking sheet with a piece of window screen that fits precisely into the bottom of the sheet.

Place the boards inside the baking sheet, fitting them in place precisely. Position a nail at one corner to drive it through both boards. Hammer the nail in until it sits flush with the wood surface. Repeat the same process with a second nail at the same corner (you may have to lift the boards slightly above the edge of the baking sheet to hammer both nails). Repeat the same process to drive two nails in each of the three remaining corners.

Fill the box with potting soil so the soil is about 1 inch below the top edge of the boards. Sprinkle the seeds you wish to plant over the surface of the soil.