Heat and limited water affect cactus germination in different ways

Cactus seeds differ in their ability to begin growing at higher temperatures and with limited water availability. A 2026 study compared five species from the southern Chihuahuan Desert, Echinocactus platyacanthus, Ferocactus pilosus, Mammillaria bocasana, Myrtillocactus geometrizans and Stenocereus huastecorum. Germination was monitored for 30 days at 25 or 32°C, with water availability controlled using polyethylene glycol solutions at water potentials of 0, −0.2 or −0.4 MPa. In Echinocactus platyacanthus and Ferocactus pilosus, the proportion of germinating seeds declined both at the higher temperature and at lower water potentials. Myrtillocactus geometrizans maintained high germination across the tested conditions, while Stenocereus huastecorum germinated better at 32°C than at 25°C. Germination of Mammillaria bocasana was constrained primarily by the higher temperature.