How to Collect and Plant Lobelia Seeds

Growing lobelias from seed is a great way to introduce a splash of color to your flower garden.

Lobelia erinus have a spreading or trailing habit which makes them ideal for window baskets, hanging baskets, containers, retaining walls or rockeries.

In this article I’ll show you how to collect and plant lobelia seeds.

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white lobelia flowers

Lobelia (Lobelia erinus) is a flowering plant that is part of the Campanulaceae family, the same plant family as bellflowers and the flowers come in a variety of shades of blue, white and pink. [1]

They bloom from mid spring to early fall and grow best in a spot with dappled light or partial shade.

Lobelias can be grown as annuals in areas with cold winter temperatures or perennials in temperate climates.

Lobelia plants attract both butterflies and bees when in bloom, making it them an attractive addition to your yard.

lobelia flowers

How to collect lobelia seeds

Collecting seeds from lobelia plants can be a bit tricky because the seeds are so tiny.

The best way I’ve found to collect the seeds is to look underneath the plants to find the spent brown flowers.

Hold a paper plate underneath the dried flowers and gently pick them off the plant.

Carefully open each one to see if there are any seeds inside.

Most of the seed pods will be empty but you’ll only need a few to get plenty of seeds to plant.

Store the seeds in an envelope or paper bag in a cool, dry place until you’re ready to plant them.

collecting lobelia seeds

How to plant lobelia seeds

Lobelia seeds are best started indoors 8 to 12 weeks before planting out in the garden.

Lobelia seeds need light to germinate so they need to be sown on the surface of moist seed starting mix.

Lightly press the seeds down but don’t cover them with soil.

The soil should be kept moist at all times to give the the best chance of germinating.

Place the pot under a humidity dome and keep the lobelia seeds at a temperature of about 70 degrees Fahrenheit (21 degrees Celsius), keeping the soil moist by spraying it with water once or twice a day.

Lobelia seedlings should be thinned when they are about an inch (2.5 cm) tall.

Once the seedlings reach 2 inches (5 cm) tall they can be transplanted out to the garden or to a container (as long as there is no chance of frost).

Space the seedlings about 4 inches (10 cm) apart and keep them well watered for their first few weeks in your garden.

Lobelia seedlings can be affected by damping off, a fungal disease that causes stem rot so be careful not to overwater the plants.

growing lobelia flowers

Caring for seed grown lobelia plants

Lobelias can be fertilized every two weeks during the growing season with a liquid plant food.

You’ll also need to remove the spent flowers regularly once lobelia plants start blooming.

This will encourage more flowers to grow and allow the plant to remain healthy all season long.

Lobelia seeds can be collected when the plant dies back in fall, although you should leave some for reseeding so you can have more plants the following year.

lobelia flowers


So there are my tips for planting lobelia seeds in your garden.

By following these steps, you should have no problem getting your seeds to germinate so you can enjoy these pretty flower plants in your garden.

Lobelias are fairly disease resistant and they’re great for containers or for growing in hanging baskets.

Have you tried collecting or planting lobelia seeds? Let me know in the comments below.

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Kelly Martin

Hi, I'm Kelly Martin, a landscape gardener and designer with over 10 years experience. I have a passion for small space gardening and I love designing and creating beautiful outdoor spaces that maximize the potential of small urban gardens. Read more

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