This source reports 4 treatments. All are shown.
Protocol 1
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around March 15, 2027 for a May 3 last frost.
- 1
Sow outdoors and leave it
No stated waiting before sowing. Germination time not stated; 21 days assumed.
26% germination.
Outdoors beats every bench treatment Deno tried.
This source doesn't state how long.
Protocol 2
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around March 26, 2027 for a May 3 last frost.
- 1
Cold moist stratification
Temperature: 40°F 4°C
4%, over 4-8 weeks.
- 2
Warm moist stratification
Temperature: 70°F 21°C
A further 18%, in 2-10 days.
No stated waiting before sowing. Then 10 days to germinate.
18% germination in 2–10 days.
4% in the cold, then 18% after the move -- better than sowing warm outright.
This source doesn't state how long.
Protocol 3
DerivedN. C. Deno, 1993Difficulty High Rated by us, not by the source.
Start around March 22, 2027 for a May 3 last frost.
- 1
Sow on the surface — do not cover
Temperature: 70°F 21°C · Light: light
No stated waiting before sowing. Then 14 days to germinate.
11% germination in 3–14 days.
11% in light against 2% in dark.
Protocol 4
DerivedN. C. Deno, 1993Difficulty Very high Rated by us, not by the source.
Start around March 15, 2027 for a May 3 last frost.
- 1
Sow and cover
Temperature: 70°F 21°C · Light: dark
No stated waiting before sowing. Germination time not stated; 21 days assumed.
2% germination.
2%. The worst of the four.