How to Grow Begonia
Begonia
Sow begonia seeds on the surface of moist compost in January-February at 21°C — they need light and are extremely slow to start. Alternatively, start tuberous types from dormant tubers in March. Plant out after the last frost into partial shade, spacing 20-25 cm apart. Water at soil level, feed fortnightly, and deadhead regularly. Lift tuberous types after the first frost and store dry over winter.
When to Start
Start seeds indoors 12 weeks before your last frost date. Transplant outdoors once night temperatures stay above 10°C and soil has warmed to at least 18°C.
Don't know your frost date? Find it here →
Growth Stages
Approximate days from start
Care Essentials
- Balanced liquid feed fortnightly during the growing season.
- Excellent for shade. Tuberous begonias give the most spectacular flowers. Don't overwater.
Growing Conditions
- Min. soil temperature
- 18°C+
- Germination temperature
- 21–25°C
Pet Safety
- Sow indoors
- —
- Transplant out
- —
- First harvest
- —
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Spacing & Planting
| Plant spacing | 25 cm |
| Row spacing | 25 cm |
| Sow depth | 0 cm |
| Mature height | 30 cm |
| Mature spread | 25 cm |
Versatile bedding plant for shade and partial shade. Tuberous types need lifting in autumn. Semperflorens types are seed-grown annuals. Excellent for containers and borders.
Pests & Diseases
Pest Vine Weevil
Identification: Adults are dull black beetles with a long snout, active at night. Larvae are white C-shaped grubs with brown heads found in compost around roots. Plants wilt despite moist soil.
- Nematode biological control (Steinernema kraussei) applied to compost in late summer
- Hand-pick adults at night with a torch
- Check root balls when repotting and remove grubs
- Systemic vine weevil drench for containers
Pest Slugs and Snails
Identification: Irregular holes in fleshy leaves and stems, slime trails, worst in wet weather
- Beer traps
- Copper tape around containers
- Evening hand-picking
- Nematode biological control
- Ferric phosphate slug pellets
Pest Aphids
Identification: Small green or pink insects clustering on soft new growth and flower buds, sticky honeydew on leaves
- Insecticidal soap spray
- Encourage natural predators
- Wipe off with a damp cloth
- Fatty acid sprays
Disease Powdery Mildew Erysiphe spp.
Symptoms: White powdery coating on leaves and stems, leaves may curl and distort
Treatment: Remove badly affected leaves, improve air circulation
Prevention: Avoid overhead watering, ensure good spacing, water at soil level
Disease Grey Mould (Botrytis) Botrytis cinerea
Symptoms: Fuzzy grey mould on flowers, leaves, and stems, often starting on dead or damaged tissue
Treatment: Remove affected parts immediately, improve ventilation and reduce humidity
Prevention: Remove spent flowers and dead leaves promptly, avoid overcrowding, water at soil level
Growing Conditions
| Min. soil temperature | 18°C |
| Germination temperature | 21–25°C |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Begonia?
- Plant Begonia 25cm apart with 25cm between rows.
- When does Begonia flower?
- Begonia typically flowers approximately 60 days after transplanting.
- Is Begonia frost hardy?
- Begonia is classified as Tender.
