This source reports two treatments. Both are shown.
Protocol 1
DerivedN. C. Deno, 1993Difficulty Low Rated by us, not by the source.
Start around March 26, 2027 for a May 3 last frost.
- 1
Sow and cover
Temperature: 70°F 21°C · Light: either
No stated waiting before sowing. Then 10 days to germinate.
70% germination in 8–10 days.
70% inside ten days with nothing done to it. Light made no difference.
Protocol 2
DerivedN. C. Deno, 1993Difficulty Low Rated by us, not by the source.
Start around March 15, 2027 for a May 3 last frost.
- 1
Cold moist stratification
Temperature: 40°F 4°C · Light: either
70%, in the third week -- it germinates in the cold.
No stated waiting before sowing. Then 21 days to germinate.
70% germination in 21 days.
The same 70% in the cold, a fortnight slower. Light made no difference.
This source doesn't state how long.