How to Grow Cobaea
Cobaea scandens
Cobaea is a vigorous half-hardy annual climber producing large bell-shaped flowers that open green and age to deep violet-purple, borne on long stalks from midsummer to frost. Sow seeds on edge indoors in late winter with bottom heat. Pot on and harden off after the last frost, then plant out against a warm wall or sturdy trellis. Provide strong support as the vine can reach 3-4 metres. Feed regularly and tie in stems as they grow. An impressive flowering screen for a single season.
When to Start
Sow indoors 6 weeks before last frost, or direct sow outdoors after frost risk has passed and soil reaches 15°C.
Don't know your frost date? Find it here →
Growth Stages
Approximate days from start
Care Essentials
- Feed fortnightly with a balanced liquid fertilizer once established and growing strongly. Switch to high-potash feed when buds form.
- A vigorous half-hardy annual climber reaching 3-4 metres in a single season. Flowers open green and age to deep purple. Needs a warm sheltered spot and sturdy support. Sow early indoors as it needs a long season to flower well.
Growing Conditions
- Min. soil temperature
- 15°C+
- Germination temperature
- 18–24°C
Enter your last frost date to see your dates
- Sow indoors
- —
- Transplant out
- —
- First harvest
- —
Want your full season plan with reminders? Try Leaftide free
Spacing & Planting
| Plant spacing | 60 cm |
| Row spacing | 60 cm |
| Sow depth | 1 cm |
| Mature height | 400 cm |
| Mature spread | 150 cm |
Give each plant a dedicated support structure. Vigorous climber that can reach 3-4 metres in a single season. Allow space for spread along trellis or fence.
Growing Conditions
| Min. soil temperature | 15°C |
| Germination temperature | 18–24°C |
| Base growth temperature | 10°C |
| Min. daylength to start | 12h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Cobaea?
- Plant Cobaea 60cm apart with 60cm between rows.
- When can I harvest Cobaea?
- Cobaea is ready to harvest approximately 70 days after transplanting.
- Is Cobaea frost hardy?
- Cobaea is classified as Half Hardy.
