Pelargonium Seeds: How to Sow, Grow, and Care for Pelargoniums from Seed
Pelargonium seeds are an excellent way to grow colourful, long-flowering plants for pots, hanging baskets, window boxes, and summer borders. Often confused with true geraniums, pelargoniums are tender perennials most commonly grown as annuals in the UK. Starting them from seed is economical, rewarding, and allows you to grow large numbers of plants in a wide range of colours and forms.
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Geraniums (Pelargoniums) are classic, colourful garden and patio favourites that bloom all summer long with the right care.
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This in-depth guide explains what pelargonium seeds are, how to sow them successfully, how long they take to grow, and how to care for plants from seed right through to flowering and overwintering.
What Are Pelargonium Seeds?
Pelargonium seeds are produced after flowers fade and seed heads develop. Each seed has a distinctive curled tail or awn, which helps it drill into soil naturally in the wild. This unique shape makes pelargonium seeds easy to recognise.
Key features of pelargonium seeds:
- Long, narrow seeds with a corkscrew-style tail
- Dark brown to black when mature
- Large enough to handle easily
- Good germination when fresh
Seeds are usually sold clean and without the long awn attached, making them easier to sow in compost.
Are Pelargoniums Easy to Grow from Seed?
Yes. Pelargoniums are considered easy to grow from seed, especially when started indoors with warmth and light.
Benefits of growing pelargoniums from seed include:
- Cheaper than buying young plants
- Wider choice of colours and flower types
- Stronger, healthier plants
- Better resistance to stress and disease
- Ideal for growing in large numbers
While they take longer to flower than cuttings, seed-grown plants are often more vigorous.
Pelargonium vs Geranium: What’s the Difference?
Pelargoniums are often called “geraniums,” but they are botanically different plants.
- Pelargoniums are tender and not frost hardy
- True geraniums (hardy geraniums or cranesbills) survive UK winters outdoors
Pelargonium seeds grow plants suitable for summer displays, not permanent outdoor planting.
Types of Pelargoniums You Can Grow from Seed
There are several main types of pelargoniums commonly grown from seed.
Zonal Pelargoniums
- Upright growth
- Rounded leaves with dark zones
- Large flower heads
- Ideal for pots and bedding
These are the most popular pelargoniums for seed growing.
Ivy-Leaved Pelargoniums
- Trailing or cascading habit
- Ideal for hanging baskets
- Glossy ivy-shaped leaves
Some varieties are available from seed, though many are grown from cuttings.
Seed-Raised Hybrid Pelargoniums
- Bred specifically for uniform growth
- Reliable flowering
- Compact habit
These are widely used for bedding schemes and containers.
When to Sow Pelargonium Seeds (UK)
Pelargoniums need a long growing season, so early sowing is important.
Best Sowing Time
- January to March indoors
Earlier sowing gives plants enough time to grow large and flower well by summer.
Late Sowing
- April sowing is possible
- Plants may flower later in summer
Outdoor sowing is not recommended in the UK due to temperature requirements.
Do Pelargonium Seeds Need Heat to Germinate?
Yes. Pelargonium seeds need warmth.
- Ideal germination temperature: 20–25°C
- Cooler temperatures slow or prevent germination
A heated propagator or warm indoor location is strongly recommended.
How to Sow Pelargonium Seeds
What You’ll Need
- Seed trays or small pots
- Fine seed compost
- Water spray or gentle watering can
- Clear lid or plastic cover
Step-by-Step Sowing
- Fill containers with moist seed compost
- Firm gently but do not compact
- Place seeds on the surface
- Cover lightly with a thin layer of compost or vermiculite
- Water gently
- Cover to retain humidity
- Place in a warm, bright location
Do not bury pelargonium seeds deeply.
How Long Do Pelargonium Seeds Take to Germinate?
- Usually 7–21 days
- Some may take up to 4 weeks
- Uneven germination is normal
Keep compost moist but never waterlogged during this period.
Light Requirements for Seedlings
Once seedlings appear:
- Remove covers immediately
- Place in bright light
- Avoid dark or shaded windowsills
Insufficient light causes leggy, weak plants that struggle later.
Pricking Out Pelargonium Seedlings
Seedlings should be pricked out when they have:
- Two true leaves
- Strong stems
How to Prick Out
- Lift gently using a label or dibber
- Handle by leaves, not stems
- Plant into individual pots
- Use free-draining compost
Water lightly after transplanting.
Growing Pelargoniums On from Seed
As plants grow:
- Keep in a bright, frost-free position
- Turn pots regularly for even growth
- Avoid overwatering
Pelargoniums prefer compost to dry slightly between watering.
When to Pot On Pelargoniums
Pot on when roots fill the pot.
- Move up one pot size at a time
- Avoid over-potting
- Firm compost gently around roots
Steady potting on encourages strong root systems and compact growth.
Pinching Out Pelargoniums
Pinching out encourages bushier plants.
When to Pinch
- When plants are 10–15 cm tall
How to Pinch
- Remove the growing tip above a leaf joint
This delays flowering slightly but results in more flowers overall.
When Can Pelargoniums Go Outside?
Pelargoniums are frost tender.
- Only move outdoors after the last frost
- Usually late May in most UK areas
Harden off plants gradually over 7–10 days.
Where to Grow Pelargoniums
Pelargoniums thrive in:
- Full sun
- Sheltered positions
- Containers and baskets
They perform best in warm, bright conditions.
Soil and Compost Requirements
Pelargoniums need:
- Free-draining compost
- Moderate fertility
- Good airflow around roots
Avoid heavy, water-retentive soil.
Watering Pelargoniums Grown from Seed
- Water when the compost surface feels dry
- Avoid standing water
- Reduce watering in cool weather
Overwatering is the most common cause of failure.
Feeding Pelargoniums
Pelargoniums are hungry plants once established.
- Start feeding when buds appear
- Use a high-potash liquid feed
- Feed weekly during flowering
Avoid high-nitrogen feeds which encourage leaves at the expense of flowers.
How Long Do Pelargoniums Take to Flower from Seed?
- Usually 16–20 weeks from sowing
- Earlier sowing gives earlier flowers
- Pinching delays flowering slightly
Plants continue flowering right through summer with deadheading.
Deadheading Pelargoniums
Regular deadheading:
- Encourages continuous flowering
- Keeps plants tidy
- Reduces disease risk
Remove entire flower stems once blooms fade.
Common Problems When Growing Pelargoniums from Seed
Leggy Seedlings
- Caused by low light or excess heat
- Move seedlings to brighter conditions
Poor Germination
- Temperature too low
- Old seed
- Compost too wet
Yellow Leaves
- Overwatering
- Nutrient deficiency
Pests and Diseases
Pelargoniums grown from seed are relatively trouble-free.
Possible issues include:
- Aphids
- Whitefly
- Botrytis in damp conditions
Good ventilation and correct watering prevent most problems.
Can You Save Seeds from Pelargoniums?
Yes, but results vary.
- Hybrid plants may not come true
- Seed heads take time to develop
- Seeds must be fully mature
Saving seed is possible but less reliable than buying fresh seed.
Overwintering Pelargoniums Grown from Seed
Pelargoniums are tender but can be overwintered.
Methods
- Bring pots indoors before frost
- Keep in bright, frost-free conditions
- Reduce watering significantly
Plants can be cut back in spring to encourage fresh growth.
How Long Do Pelargoniums Live?
- Treated as annuals in the UK
- Can live for several years if overwintered
- Best displays are from young plants
Many gardeners grow new plants from seed each year.
Common Mistakes to Avoid
- Sowing too late
- Insufficient warmth at germination
- Overwatering seedlings
- Planting outdoors too early
- Overfeeding with nitrogen
Correct timing and care prevent most failures.
Why Grow Pelargoniums from Seed?
Growing pelargoniums from seed is popular because:
- Seeds are affordable
- Plants are strong and uniform
- Large displays can be grown cheaply
- Excellent for baskets and containers
- Long flowering season
Few plants give as much colour for as little effort.
Final Thoughts: Pelargonium Seeds
Pelargonium seeds are a reliable and rewarding way to grow vibrant summer plants for containers, baskets, and bedding displays. With early sowing, warmth, good light, and careful watering, seedlings grow into strong, floriferous plants that perform for months.
By starting pelargoniums from seed, you gain control over timing, variety choice, and plant quality — making them a firm favourite for gardeners who want maximum impact at minimal cost.