Submerge orchid stems in water and cut to the desired length. Cutting the stems keeps the flowers fresh. Keep the stems submerged for at least 15 minutes.
Fill the bottom of a vase with sand. Tie a washer to the bottom of the orchid stem. Poke the stem into the bottom of the sand. Cover the base of the stem with shells, rocks or glass beads to weigh it down.
Add a few orchids if you like. Fill the vase carefully with water until the orchids appear to be floating at the top.
Submerge orchid stems in water for at least 15 minutes and cut to the desired length.
Use a round weight at the bottom of the vase that has openings to stick in the orchid stems. Check at craft shops or online to find the weight that's called a "flower frog." Place the orchid stems into the flower frog. Cover the weight with decorative rocks, beads or crystals.
Fill the vase with water and add some votive candles to float alongside the orchids. You can also snip off the orchid stems near the flower so the blooms float with the candles.
If lighted candles are not allowed at your venue, put a submersible LED light at the bottom of the vase.