The male and female strobili are borne separately on different branches. Redwood begins producing seeds at 5 to 15 years of age. A dry period during pollination allows better pollen dispersal and improves seed viability. Redwood seeds do not require pretreatment to germinate. Germination rates are generally low due to low viability rather than to dormancy.
Seedlings require adequate moisture to survive.
The roots of redwood seedlings do not have root hairs and are thus inefficient at extracting soil moisture. Once established seedlings can obtain remarkable growth rates in the first season. Redwoods can reproduce asexually by layering or sprouting from the root crown or stump. Redwood occurs in a maritime Mediterranean climate, where the winters are cool and rainy, and the summers are dry. The fog reduces the drought stress of this hydrophilic plant by reducing evapotranspiration and adding soil moisture.