Ipomoea is an annual climbing plant prized for rapid growth and abundant, colourful trumpet-shaped flowers. Easy to grow, it can be sown directly outdoors as soon as temperatures warm up or sown under cover to obtain earlier flowering. To encourage rapid germination, it is recommended to soak Ipomoea seeds in water for 24 hours before sowing. Discover when and how to sow Ipomoeas to enjoy vigorous growth all summer.
Good practices for successful sowing of ipomoeas
| ✅ To do | ❌ To avoid |
|---|---|
| Soak seeds for 24 hours before sowing | Sow dry seeds in cold soil |
| Sow in a warm, sunny position | Place Ipomoeas in shade |
| Keep compost slightly moist | Let compost dry out after sowing |
| Provide support for voluble stems | Wait until plants are developed before staking |
| Sow after last frosts | Sow too early outdoors |
When to sow ipomoeas?
Ipomoeas can be sown in two ways. For earlier flowering, carry out sowing under cover in March or April at around 18 °C. Young plants are planted out after last frosts.
It is also possible to sow directly outdoors or in pots from May to June, when soil has warmed sufficiently. In all cases, soak seeds in water overnight before sowing to aid germination.
How to sow ipomoeas under cover?
Materials required :
- Ipomoea seeds
- pots, pots, transparent cover or a mini greenhouse
- Seed and potting compost (see product)
- A mister or watering can with a fine rose
- Transparent lid or plastic film
Sowing under cover allows gaining several weeks on flowering.
- Fill perforated pots with a compost suitable for sowing.
- Moisten compost lightly.
- Sow 3 to 4 seeds per pot about 1 cm deep.
- Cover with a thin layer of compost then water gently.
- Cover with a transparent lid or plastic film.
- Place pots in light, avoiding direct sun.
- Keep compost moist until germination.
- Vent daily to reduce risk of damping-off.
- Remove protection gradually when seedlings appear.
- Plant young Ipomoeas out after last frosts, spacing about 40 cm apart.
How to sow ipomoeas directly outdoors?
Materials required :
- Ipomoea seeds
- spade, broad fork, hoe to prepare soil
- transplanting trowel
- Well-rotted compost or potting compost
- Watering can with fine rose
Direct sowing is the simplest method once temperatures have warmed.
- Loosen soil to around 10 cm depth.
- Work in well-decomposed compost.
- Use trowel to make holes spaced 50 cm to 1 m apart depending on variety vigour.
- Place 4 to 5 seeds in each hole.
- Cover with fine soil then press lightly.
- Water with a fine spray.
- Keep soil moist until germination.
First shoots usually appear after two to three weeks depending on soil temperature.
How to sow ipomoeas in containers?
Ipomoeas are easily grown in troughs or large pots on a sunny terrace.
- Choose a container at least 30 cm in diameter with drainage holes.
- Place a layer of gravel or clay pebbles for drainage.
- Fill with compost suitable for flowering plants.
- Sow seeds in a cluster of 4 to 5 seeds.
- Cover lightly with compost then water.
- Place container in a warm, sunny spot.
- Provide a trellis or canes early to support stem growth.
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