Primrose — Growing reference
| Scientific name | Primula vulgaris |
|---|---|
| Seed germination (days) | 21–28 |
| Soil temperature for germination (°C) | 10–15.6 |
| First harvest or flowering (days) | 90–150 |
| Measured from | Transplant |
| Plant spacing (cm) | 22.9–30.5 |
| Mature height (cm) | 15.2–25.4 |
| Mature spread (cm) | 22.9–30.5 |
| USDA hardiness zones | 4–8 |
| Light | Partial sun |
| Water | Moderate |
| Sowing method | indoor-start |
Growing directions
Start seeds at cool temperatures (50–60°F) in moist seed-starting mix with seeds pressed on the surface; germination requires light and cool stratification, so refrigerate freshly sown trays at 35–40°F for three weeks before moving to a bright, cool location. Transplant into partially shaded, moist, well-drained, humus-rich soil; primroses bloom prolifically in the cool dappled light under deciduous trees where spring sun reaches before the canopy leafs out. In zone 4–6 they are fully hardy perennials that return reliably each spring; in zone 7–8 treat them as cool-season annuals that perform best from fall through late spring and then go semi-dormant in summer heat. Divide overcrowded clumps in early fall every 2–3 years to maintain vigor.
Source and local conditions
Typical planning ranges from OpenPlantDB (CC0). Cultivar, climate, season and growing method can change these values. Confirm the seed label and local guidance before planting.
Source & verification
OpenPlantDB · CC0