Native to Southwestern US, Mexico and South America, zinnias grow rapidly and require little care. These daisy-like flowers range in color from white to fiery reds and oranges, making them ideal for a boost of color to any garden. Zinnias range in size from dwarf varieties (8-10 inches), to 4-foot giants. Seeds are produced at the base of the petals, making saving seed quick and easy.
Select healthy plants with the biggest and brightest blooms and mark them for seed collection. Keep in mind that you want to encourage the best traits and to do that you must harvest seeds from plants that exhibit those traits.
Allow zinnias to mature on the stalk. These striking flowers maintain their beauty for a week or more while new blooms open. Be patient. Zinnias do eventually fade and set seed. Picking the blooms before they have faded results in immature seed that may rot or fail to germinate.
Harvest zinnias on a cool, dry day. Pick with a 6 to 8 inch stem. Strip leaves from the stem and form small bundles of six to eight stems. If you grow more than one color, it is wise to dry bundles of the same color zinnias for easy storage of separate colors. If you prefer mixed colors, you can dry them together to produce mixed seed. Secure with twine or bind with elastics.
Hang upside down in a well-ventilated area to dry completely. An attic or workshop area is ideal as humidity is generally low. Check every two or three days for any signs of mold and turn the bundles to dry evenly, if necessary.
Remove from bundles when petals are dry and brittle. Line your work area with old newspapers and remove the petals from the stems by rubbing the blooms between your hands. Petals will crumble exposing the seeds. Remove chaff and debris, saving just the seed.
Store in an airtight container. Glass jars or zippered seed storage bags are a great choice. Keep in a cool dark area like a closet or drawer. Label with date, color and size.