In experiments with 6-month-old seedlots, 7-day germination for unchilled seeds at 10 to 20 °C was 10% for 1 lot of green Mormon-tea, 49 to 54% for 2 lots of Nevada Mormon-tea, and 95 to 100% for 3 lots of Torrey Mormon-tea. The 7-day germination after 2 weeks of chilling at 1 °C was over 90% for all seedlots. Germination is generally highest at temperatures of 15 to 20 °C, except in more dormant lots, which show higher percentages of germinatation in temperature regimes that include a temperature in the chilling range (Young and others 1977). Germination is suppressed by higher temperatures, which probably prevent the otherwise nondormant seeds from precocious summer germination. Ephedra seeds germinate readily during prolonged chilling. Kay and others (1977) reported 76% germination during a 30-day stratification at 2 °C for a Mojave desert collection of Nevada Mormon-tea. In chilling experiments with the 6 seedlots mentioned above, weeks to 50% germination at 1 °C varied from 6 to 7 weeks for the Torrey Mormon-tea collections and from 8 to 9 weeks for collections of the other 2 species. All viable seeds germinated during chilling within 12 weeks.
Kyle Neath wrote:
In my own research, it really deeply depends on the specific species, and even then stratification is all about increasing chances of germination. No stratification may germinate 10%, while a cold stratification may germinate 60%, but scarification and a cold stratification may germinate 95%. For example this guide on growing Ephedra has this complicated bit on germinating the seeds:
Joseph Lofthouse wrote:
My strategy towards cold stratification is that nature does it better than a refrigerator or freezer, so I just plant things in the fall, winter, or super early spring, and let mother take care of it in her own way.