^{(Photograph: Stenocereus gummosus, el Vizcaino, Baja California del Sur, Amante Darmanin)}

Introduction

Seeds of wild plants need special conditions to germinate: “…seeds may readily germinate following an early summer rain, but fail to respond to winter rains when air temperatures are lower.”

The Details

La Barrera and Nobel (see attached manuscript) studied seed germination in Stenocereus queretaroensis. They found that the best germination was at 68F to 86F (20C to 30C), with a bit of water in the soil, and in light (but not hot burning sun). The seeds also needed to be a year or a year-and-a-half old.

Moist soil, not too hot and not too cold, well-ripened seeds, and bright light (not full sunlight) sounds like conditions under a shrub in the spring or early summer. S. queretaroensis has evolved to germinate when conditions are just right for seedlings to survive. It all makes sense. Probably many cacti have evolved to take advantage of spring weather.

Stenocereus queretaroensis Seed Germination