Cut poppy blossoms from the plant before the flowers open. Wait until just before the flower opens. Learn what your poppy blossoms look like by observing their habits for a short time after they begin blooming in summer. Cut stems at a 45-degree angle and sufficiently long by snipping them at the base of the plant or where it attaches to a main stem.
Seal the stem of each flower by burning it with a match or lighter. Seal the stems immediately after cutting before you place them in water.
Mix purchased floral preservative to the flower vase's water.
Cut 1/4 inch from the base of each flower stem every other day, and then reseal the cut by exposing each stem to a flame.
Change the water in the vase every other day. Add fresh floral preservative each time you change the water.