Pick your theme. For colorful flags to mark the crops and flowers, use stencils for a big, juicy tomato, a bunch of carrots, an open pea pod or a purple eggplant -- whatever your garden grows. For flowerbeds, choose a single sunflower, a bunch of daffodils or tulips, day lilies or a pansy face. Set out the fabric paints to match the designs you chose.
Cut fabric to make standard 12-by-18-inch flags, being sure to leave an extra 2 inches on the length for the folded-over top hem. If you won't hem the flags, the fabric will be 12 inches wide by 20 inches long. If you will hem them, allow for a 3/4-inch hem all the way around.
Fold the top of each flag over 1 inch and use the sewing machine to run a straight seam across it, forming a "sleeve" at the top of the flag to slip over the flag post. Lay the fabric flat on the work surface, front side up, and position the stencil.
Trace the outline of the art very lightly with a pencil. If you are adding the name of the image -- T O M A T O, for instance -- then stencil the letters at the bottom of the flag.
Paint the images with fabric paint. If the fabric absorbs the paint unevenly, let each coat dry and add more paint until you achieve the level of opacity you want. Paint the background colors first and add any detail once the basic colors are dry. Paint, or outline in permanent marker, stenciled lettering last. Let the paint dry.
Heat the fabric paint to set it. Use a hairdryer set on high or follow manufacturer's directions for ironing the fabric. Once the paint is set and the fabric is cool, further protect it with a spray coat of crystal-clear finish. Now hang your handmade, custom garden flags on the posts and use them to conjure up prize-winning salad fixings and flowers.