Remove the cover from the original cushion of a Morris chair. Stretch the cover on a flat surface, and measure the length, width and height. If there is no cushion to measure, measure the width and length of the space on the chair where the cushion will sit. A cushion for a Morris chair is square, so the length and width should be the same. The height should be approximately 4 to 6 inches. Write these numbers on a piece of paper, because you will need them later.
Add 1 inch to all measurements. Cut out two pieces of fabric to match the length and width measurements; these are the top and bottom panels of the cushion. Cut two pieces of fabric to match the height and width measurements; these are the two side panels. Cut two more pieces of fabric to match the height and length measurements; these are the front and back panels of the cushion. These will be the six sides of the cushion.
Cut the back panel in half lengthwise. Lay one half of the panel down on a flat surface with the good side facing up.
Place a zipper facedown on top of the half panel. Position the bottom of the zipper 1 inch from the sides of the panel. Align the lengthwise edges of the panel and the zipper together, and pin the zipper in place.
Place the other half of the back panel on a flat surface. Align the other side of the zipper with the length of the panel. Pin in place. You should now have one whole panel with a zipper running through the center.
Sew along the length of the panel to secure the zipper in place. Remove the pins.
Place the front panel and a side panel on top of each other. Pin the two together at the height edge. Ensure that the good sides of the fabric are facing each other.
Open the pinned fabric; it should now be one long piece of fabric. Place a side panel on top of the front panel. Pin these together on the side that doesn't have a panel already pinned. There should now be three panels making one long strip.
Pin the back panel to both side panels, creating an open square.
Sew all along the four pinned corners. Remove the pins.
Place the top panel on a flat surface facing up. Place piping along the edge of the panel. Place the square side strip over the panel. Line up the corners, and pin the panel, piping and strip together. Sew all three pieces together at the edge. Remove the pins. Repeat with the bottom panel.
Measure and cut batting, using the measurements you wrote down. Glue each piece of batting to the appropriate side of the foam. This will prevent the batting from bunching when putting the cover on.
Open the zipper of the cover, and put the foam cushion inside the cover. Close the zipper.
Repeat Steps 1-13 to make the second cushion.