Fill a 2-inch-deep nursery tray with potting soil that contains 25 percent perlite. Spray the soil with water until the the top inch feels moist.
Lay out the Banisteriopsis caapi seeds on the surface of the soil. Space the seeds 1 inch apart.
Press the seeds into the soil until they are just beneath the surface. Spread a 1/8-inch-thick layer of medium-grit sand across the surface of the soil.
Drape a single layer of plastic wrap over the nursery tray to create a greenhouse-like environment around the seeds. Do not seal the plastic wrap around the tray.
Place the nursery tray atop a warming mat. Set the temperature on the warming mat to between 80 and 85 F. Turn down the temperature to 68 F at night.
Position a fluorescent lamp 15 inches above the nursery tray to provide the Banisteriopsis caapi seeds with light for eight to 10 hours each day. Turn off the lamp at night.
Moisten the soil around the Banisteriopsis caapi seeds whenever it feels dry to the touch. Spritz the soil with a water-filled spray bottle until the top 1/2 inch feels moist.
Remove the plastic wrap whenever it collects condensation to prevent the accumulation of excess moisture, which will lead to fungal infections. Let the soil air out for 15 to 20 minutes before replacing the plastic wrap.
Watch for signs of germination 25 to 30 days after sowing the Banisteriopsis caapi seeds. Keep the seedlings in the nursery tray until they grow to at least 2 inches in height.
Transplant the seedlings into individual 4-inch plastic pots filled with potting soil once they unfurl their second pair of leaves. Keep the individually potted Banisteriopsis caapi seedlings under very warm and bright conditions at all times.