Summer Bulbs to Plant in January indoors

Summer Bulbs to Plant in January indoors

January may feel like the quietest month in the garden, but it’s actually the perfect time to get ahead for a spectacular summer display. While most summer-flowering bulbs won’t tolerate frost outdoors, many can be started indoors or in a greenhouse during January. By doing so, you’ll enjoy earlier blooms, stronger plants, and a longer flowering season once warmer weather arrives.

Below is a guide to the best summer bulbs to plant in January in the UK, along with tips on how to grow them successfully.


Why Plant Summer Bulbs in January?

Starting summer bulbs early gives them a head start before spring arrives. In the UK’s unpredictable climate, this can make a big difference.

Benefits include:

  • Earlier flowering in late spring or early summer
  • Stronger root development
  • Longer flowering period
  • Better success with tender bulbs

Most bulbs planted in January should be grown indoors, in a heated greenhouse, or on a bright windowsill.


Best Summer Bulbs to Plant in January (UK)

1. Begonias

Begonias are ideal for pots, hanging baskets, and shaded borders.

  • How to plant: Start tubers in shallow trays or pots with compost, hollow side facing up
  • Where: Indoors or heated greenhouse
  • Flowering: June to October

They thrive in partial shade and are perfect for patios and balconies.


2. Dahlias

Dahlias are a favourite in UK gardens for their bold colours and long flowering period.

  • How to plant: Pot up tubers in January to encourage early growth
  • Where: Frost-free greenhouse or indoors
  • Flowering: July to first frost

Pinching early growth encourages bushier plants and more flowers.


canna flower with green leaves

3. Cannas

Canna lilies bring a tropical feel to the garden with dramatic foliage and flowers.

  • How to plant: Start rhizomes in large pots
  • Where: Warm indoor location or greenhouse
  • Flowering: July to September

They prefer rich compost and plenty of water once established.


Pink Gloxinia

4. Gloxinia

Gloxinia are compact, colourful plants ideal for indoor displays.

  • How to plant: Shallow planting in light compost
  • Where: Indoors only
  • Flowering: Late spring to summer

These are best grown as houseplants rather than garden plants in the UK.



How to Care for Summer Bulbs Started in January

To ensure success, follow these simple tips:

  • Use free-draining compost
  • Water lightly until growth appears
  • Keep bulbs frost-free
  • Provide bright light but avoid scorching sun
  • Gradually harden off plants in spring

Once temperatures consistently stay above freezing (usually late April or May in the UK), plants can be moved outdoors.


When to Plant Summer Bulbs Outside

Most summer bulbs cannot be planted directly into the ground until after the last frost. In the UK, this is typically:

  • Late April in the south
  • Early to mid-May in northern regions

Starting them in January ensures they are well-established and ready to thrive.


January is the perfect month to plan ahead and start summer bulbs indoors. By planting early, you’ll be rewarded with healthier plants, earlier flowers, and a vibrant garden throughout the summer months.

If you want a head start on colour and impact, don’t wait for spring—get planting now.

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