Overview
Vernalization means a plant needs a cold spell before it can flower. In the game, English lavenders and lavandins must collect enough chill weeks during winter dormancy. Until they do, they grow leaves but stay at stage 3 and cannot be harvested for flowers.
This is why a lavender planted in spring will usually not bloom until it has been through its first winter.
Who needs chill
| Cultivars | Chill weeks | Where the number comes from |
|---|---|---|
| Munstead | 10 | A published cultivar study (game target inside a 5–15 week range) |
| Other English lavenders | 10 | Group estimate (10–15 week range) |
| Lavandins (× intermedia) | 12 | Group estimate (10–15 week range) |
| Aromatico Evolution, Aromatico Forte Blue | 0 | Their record says no vernalization is needed |
| Spanish, Portuguese, French, Chaytor's and all other groups | 0 | Unverified, so it never blocks flowering |
How chill is counted
- Chill only counts while the plant is dormant in winter.
- Each dormant week adds chill equal to the share of that week's days whose average temperature was between 35°F and 50°F. A week where every day was in that range counts as one full chill week.
- Days colder than 35°F or warmer than 50°F do not count.
- Once the total reaches the target, the plant is marked as vernalized and can bud and bloom in its next bloom window.
Until the target is met
- A plant at stage 3 or higher is held at stage 3, in the forcing phase: "remains vegetative until its modeled chill target is met".
- All flower harvests stay closed with the message that the cultivar has not completed its modeled vernalization requirement.
- In a greenhouse, warm protected conditions never count as chill. Vernalize mode adds one chill week for each week the house is at 35–50°F; Force mode waits until the chill target is met.
Keeping track
- The Seasonal crop windows board on the Lavender Field page shows each planted cultivar's chill progress, for example "4/10 modeled chill weeks".
- Inspect shows the plant's seasonal phase: growing, quiescent, vernalizing, forcing, budding, blooming or post-bloom.
- Your phone's Crop Calendar sends a "dormancy & vernalization" notice before cold-dormancy scouting begins in late fall: 4 weeks ahead, 1 week ahead, and when it starts.
Tips
- Plant English lavender or lavandin in spring or early fall so it is established before winter and can collect its chill.
- If you want flowers without waiting for winter, try Aromatico Evolution or Aromatico Forte Blue (both Level 12), or a Spanish lavender.
- A very mild winter can leave plants short of chill. Check the board before spring.
Real-world note
The game labels its numbers carefully: Munstead's comes from a published chilling-response study, and the group numbers are estimates. It also notes that flowering depends on light, temperature and plant size, not only on chill.
See also
Written from the game itself. Spot something out of date? and our farm team will check it.
