START HERE
Quick Facts
- Sowing window
- Sow indoors from mid-February to early April at 18–21°C.
- Harvest window
- Pick green from midsummer or leave fruits to ripen red and sweeter into early autumn.
- Difficulty
- Moderate
- Container suitability
- Grow one plant in a 10–15 litre pot at least 30cm wide. Use fresh peat-free multipurpose compost, provide full sun and shelter from cold wind, and expect greenhouse-grown plants to crop most reliably in the UK.
- Frost sensitivity
- Very frost tender
- Typical time to harvest
- Allow about five to seven months from sowing to ripe fruit, depending on warmth, light and whether fruit is picked green or fully coloured.
SOW
When to Sow California Wonder 300 TMR Sweet Pepper in the UK
Sow indoors from mid-February to early April at 18–21°C.
Use that window as a practical starting point rather than a fixed deadline. In colder or exposed areas, delay outdoor sowing and planting; in mild sheltered areas, the earlier end of the range may work. Tender crops should remain protected until frost risk has passed.
Sowing Indoors
Sowing indoors is essential for California Wonder 300 TMR Sweet Pepper. Use a heated propagator or warm airing cupboard, then move germinated seedlings immediately into strong light. Sow individual seeds in small cells so roots are disturbed as little as possible when potting on.
Sowing Outdoors
Direct sowing outdoors is not recommended in the UK. Harden plants off for 7–10 days and move them outside only after frost, ideally when nights remain above 12°C. A greenhouse, conservatory or sheltered south-facing patio is safer.
PLANT
Spacing and Planting Out
Space plants 35–45cm apart under cover, or keep one plant per final pot. Stake before branches become heavy with fruit and avoid crowding, which slows drying and encourages pests.
Before planting outside, harden off indoor-raised plants over 7–10 days unless the crop is fully hardy and already accustomed to outdoor conditions. Water the planting hole or container first and avoid leaving young roots exposed to sun or wind.
SMALL SPACES
Growing California Wonder 300 TMR Sweet Pepper in Pots and Containers
Grow one plant in a 10–15 litre pot at least 30cm wide. Use fresh peat-free multipurpose compost, provide full sun and shelter from cold wind, and expect greenhouse-grown plants to crop most reliably in the UK.
Container checklist
- Use drainage holes and raise pots slightly so surplus water can escape.
- Fill with fresh peat-free compost suited to edible crops.
- Leave a watering lip below the rim and check pots more often in sun or wind.
- Use a strong support at planting time if the mature crop will climb or become top-heavy.
CARE
Watering and Feeding
Water thoroughly, then let the compost surface begin to dry before watering again. Never leave pots waterlogged. Start a high-potash liquid feed every 7–10 days once the first fruit has set.
Variety note: Grow one plant in a pot at least 30cm wide, ideally under cover; keep evenly moist and feed after fruit set.
WATCH FOR
Common Problems
Poor or uneven germination
Compost that is too cool is the usual cause. Keep it consistently warm, but move seedlings into bright light as soon as they appear.
Flowers drop without setting
Cold nights, dry compost or very high greenhouse temperatures can all interrupt fruit set. Restore steady conditions and gently tap flowers to move pollen.
Aphids and red spider mite
Check shoot tips and leaf undersides weekly. Improve ventilation and deal with small infestations before leaves become distorted.
PICK
Harvesting California Wonder 300 TMR Sweet Pepper
Pick green from midsummer or leave fruits to ripen red and sweeter into early autumn.
Allow about five to seven months from sowing to ripe fruit, depending on warmth, light and whether fruit is picked green or fully coloured. Harvest in the coolest part of the day where practical and handle produce gently. Regular picking encourages continued cropping in fruiting and cut-and-come-again plants.
GROW TOGETHER
Companion Plants
Basil, chives, dwarf nasturtiums and calendula can share the same sunny growing area, but use separate pots or leave enough root room. Mixed planting adds flowers and variety; it is not a guaranteed pest treatment.
QUESTIONS
Frequently Asked Questions
Can I grow California Wonder 300 TMR Sweet Pepper in pots?
Grow one plant in a 10–15 litre pot at least 30cm wide. Use fresh peat-free multipurpose compost, provide full sun and shelter from cold wind, and expect greenhouse-grown plants to crop most reliably in the UK.
How long does California Wonder 300 TMR Sweet Pepper take to harvest?
Allow about five to seven months from sowing to ripe fruit, depending on warmth, light and whether fruit is picked green or fully coloured.
Why is my California Wonder 300 TMR Sweet Pepper not producing fruit?
The common causes are low temperatures, weak light, irregular watering or flowers failing to pollinate. Keep the plant warm and bright, feed only after flowering and gently tap open flowers.