Seed smoking

Fynbos is a fire-driven system and although destructive in many ways and a threat to infrastructure, it also triggers regeneration amongst many fynbos plant species. Fire is an important ecological driver within the fynbos environment.

Smoking seeds acts as a seed germination cue for some fynbos species, namely Asteraceae, Ericaceae and Restionaceae. Germination enhancement has also been visible in the fynbos species of Proteaceae.  Our Horticultural students at the Green Futures College use smoke in April to prepare seeds for propagation before the winter months. Seeds are first cleaned and separated by the students. The dormancy of the seeds is broken once they are smoked.  Smoke and fire In the absence of a wildfire, smoke has proven to be highly effective, often inducing 100% germination in deeply dormant seed populations with 0% control germination from unsmoked seeds. Smoke induces germination both directly and indirectly by aqueous or gaseous transfer from soil to seeds. The seeds require the chemical in the smoke as well as the cooler night temperatures of the autumn and winter months to break their dormancy. In nature, smoke signals extra nutrients which will soon be available within the nutrient-poor fynbos soils. At Green Futures College, we imitate the season of wildfires in our region which usually burn between November and April months. The winter rainfall which follows the fire season enables a growth spurt of the seeds. The degree of success derived from the germination of seeds varies, but on average, seeds that are given our smoke treatment give at least twice the number of seedlings compared to those of unsmoked seeds.