Things You'll Need
Paintbrush or cotton swab
The dragon fruit cactus, or Hylocereus undatus, blossoms only at night. The flower lasts for one night before it perishes. The cactus depends on bats and moths for pollination. If pollination occurs, the cactus produces an oval, pink fruit that is filled with a sweet white pulp and black seeds that are relished as an edible snack. If you grow the dragon fruit cactus as a houseplant, you will have to undertake the task of hand pollinating the flowers to ensure fruit production. The dragon fruit cactus is capable of self-pollination, so you will only require one plant to produce fruit.
Dip a cotton swab or a small, pointed paintbrush into rubbing alcohol. Gently wipe the cotton swab or paintbrush against a soft cloth to remove any excess rubbing alcohol.
Stick the cotton swab or paintbrush into the yellow anthers in the middle of the flower. Spin the cotton swab or paintbrush gently in circles to shake loose as much pollen as possible. Self-fertile, the pollen will land on the flower's protruding stigma, which sits in the midst of the anthers. You can also lightly brush the paintbrush or cotton swab laden with pollen against the stigma several times to ensure pollination. Once the pollen falls on the stigma, pollination should take place.
Remove the cotton swab or paintbrush from the flower and repeat the action on another one of the plant's flowers. Continue to pollinate each flower that the cactus produces to guarantee ample fruit production.
The fruit will grow and ripen 30 to 40 days after pollination.
Sterilize the paint brush or cotton swab with rubbing alcohol between individual cacti.