Polemonium vanbruntiae
Genus Polemonium
Two sources report 10 treatments between them. All are shown.
Protocol 1
DerivedN. C. Deno, 1998Difficulty Moderate Rated by us, not by the source.
Start around September 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 16, 2026.
- 1
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
- 2
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: dark
about 6 months from start to sowing. Germination time not stated; 21 days assumed.
90% germination.
Protocol 2
DerivedN. C. Deno, 1998Difficulty High Rated by us, not by the source.
Start around September 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 16, 2024.
- 1
Dry storage
Duration: 730 days · Temperature: 70°F 21°C
- 2
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
- 3
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: dark
about 2.5 years from start to sowing. Then 21 days to germinate.
26% germination in 21 days.
Protocol 3
DerivedN. C. Deno, 1998Difficulty Moderate Rated by us, not by the source.
Start around September 29, 2026 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 28, 2025.
- 1
Dry storage
Duration: 365 days · Temperature: 70°F 21°C
- 2
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
- 3
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: dark
about 1.5 years from start to sowing. Then 9 days to germinate.
62% germination in 4–9 days.
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.
Protocol 5
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around January 18, 2027 for a May 3 last frost.
- 1
Sow and cover
Temperature: 70°F 21°C · Light: light
No stated waiting before sowing. Then 77 days to germinate.
57% germination in 7–77 days.
Protocol 6
DerivedN. C. Deno, 1993Difficulty Low Rated by us, not by the source.
Start around September 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 16, 2026.
- 1
Dry storage
Duration: 180 days · Temperature: 70°F 21°C
- 2
Sow and cover
Temperature: 70°F 21°C · Light: light
about 6 months from start to sowing. Then 21 days to germinate.
95% germination in 21 days.
Protocol 7
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around October 3, 2026 for a May 3 last frost.
- 1
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
6 germinated in this phase.
- 2
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
about 6 months from start to sowing. Then 4 days to germinate.
90% germination in 2–4 days.
Protocol 8
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around September 29, 2026 for a May 3 last frost.
- 1
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
6 germinated in this phase.
- 2
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: dark
about 6 months from start to sowing. Then 8 days to germinate.
90% germination in 4–8 days.
Protocol 9
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around September 25, 2026 for a May 3 last frost.
- 1
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
- 2
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
about 6 months from start to sowing. Then 12 days to germinate.
95% germination in 1–12 days.
Protocol 10
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around September 29, 2026 for a May 3 last frost.
- 1
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
- 2
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: dark
about 6 months from start to sowing. Then 8 days to germinate.
87% germination in 6–8 days.