Rainbow Cactus

Rainbow Cactus (Echinocereus rigidissimus) grows best when its natural cycle of strong light, freely draining soil and measured watering is respected. Give it full sun. Water it according to its seasonal needs: moderate in summer; entirely dry in winter. Plant it in very mineral, fast-draining mix. A container with an unobstructed drainage hole is essential, because moisture lingering around cactus roots can quickly lead to rot. Keep its temperature needs in mind: -5 to 35°c. cold-tolerant when dry. During active growth, check the compost before watering rather than following a rigid calendar, since heat, light and pot size all change how quickly it dries. Reduce watering during cool or dormant periods, keep the plant well ventilated, and wait until the growing medium is dry before watering again.

From seed. Sow fresh seed on the surface of a fine, sterile cactus mix and keep it warm, lightly humid and out of harsh direct sun until germination. Once seedlings are established, increase ventilation gradually and allow longer intervals between watering to reduce the risk of damping off. Young cacti are especially vulnerable to excess moisture. Use a small pot with excellent drainage, provide bright filtered light while roots establish, and move the new plant gradually into the light, temperature and watering conditions preferred by a mature Rainbow Cactus.