Primula elatior
Genus Primula
This source reports two treatments. Both are shown.
Protocol 1
DerivedN. C. Deno, 1993Difficulty 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, 2026.
- 1
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C
2 germinated in this phase.
- 2
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
- 3
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C
18 germinated in this phase.
Steps after step 2 run on after germination.
about 6 months from start to sowing. Germination time not stated; 21 days assumed.
26% germination.
Protocol 2
DerivedN. C. Deno, 1993Difficulty Very high Rated by us, not by the source.
Start around December 15, 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
2 germinated in this phase.
- 3
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
4 germinated in this phase.
- 4
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C
9 germinated in this phase.
Steps after step 1 run on after germination.
about 3 months from start to sowing. Germination time not stated; 21 days assumed.
9% germination.