Split the glued seams on an envelope from purchased seeds to use as a template. Alternately, print a template from your computer and cut it out. (See the Resources section for a template.)
Lay the template on top of a sheet of decorative paper or wrapping paper. Trace around the template onto the paper and then cut out the shape.
Fold the envelope in half where indicated on the template or where it was folded on the purchased seed packet. Fold back the two flaps on either side of the packet front.
Place a thin line of glue on the back side of the two flaps and glue them to the back of the packet to form a pocket. You can also use a glue stick, if preferred. Allow the glue to dry.
Use markers to decorate the front of the envelope with a picture of the type of plant the seeds will grow, a drawing of the plant, or any other design you like. Write the growing and care instructions for the type of plant on the back of the envelope.
Place the seeds inside the envelope. Add three or four dry rice grains to help absorb any excess moisture. Fold the top flap down and glue or tape it shut.