Skip to content

How to Grow Nemesia

Nemesia strumosa

Half Hardy Cool Season Continuous Harvest

When to Start

Sow indoors 7 weeks before last frost, or direct sow outdoors after frost risk has passed and soil reaches 10°C.

Don't know your frost date? Find it here →

Growth Stages

Sow seeds
Germination ~10d
Flowering ~80d

Approximate days from start

Care Essentials

  • Balanced liquid feed every two weeks. Light feeder — avoid overfeeding which promotes leggy growth at the expense of flowers.
  • Wonderfully fragrant bedding plant with bicoloured flowers in a huge range of colours. Thrives in cool conditions — perfect for UK spring and autumn. May stop flowering in hot spells but recovers when temperatures drop. Excellent for containers, window boxes, and bed edges.

Companion Planting

Growing Conditions

Min. soil temperature: 10°C+

Get a personalized schedule for Nemesia based on your exact frost dates

Start planning free

Enter your last frost date to see your dates

Don't know your frost date? Find it here

Spacing & Planting

Plant spacing 15 cm
Row spacing 20 cm
Mature height 25 cm
Mature spread 20 cm

For compact bedding varieties. Creates a dense, fragrant carpet of colour at this spacing.

Try our spacing calculator →

Care Guide

Feeding
Balanced liquid feed every two weeks. Light feeder — avoid overfeeding which promotes leggy growth at the expense of flowers.
Watch for
  • Aphids
  • Dislikes heat above 25°C
  • Generally trouble-free in cool conditions

Pests & Diseases

Pest Aphids

Identification: Clusters of small green insects on shoot tips, sticky honeydew, distorted growth

Organic treatment:
  • Blast off with water
  • Soft soap spray
  • Encourage ladybirds
Chemical treatment:
  • Pyrethrum-based contact insecticide
Disease Grey Mould (Botrytis) Botrytis cinerea

Symptoms: Fluffy grey mould on stems and flowers, especially in cool damp conditions. Plants rot from the base.

Treatment: Remove affected growth. Improve air circulation. Reduce overhead watering.

Prevention: Space plants for airflow. Avoid wetting foliage. Remove dead flowers and leaves promptly.

Growing Conditions

Min. soil temperature10°C
Base growth temperature7°C
Min. daylength to start10h
Photoperiod sensitivityday neutral

Frequently Asked Questions

How far apart should I plant Nemesia?
Plant Nemesia 15cm apart with 20cm between rows.
When does Nemesia flower?
Nemesia typically flowers approximately 40 days after transplanting.
Is Nemesia frost hardy?
Nemesia is classified as Half Hardy.

Calculate your harvest date →

Plan Nemesia in your garden — get personalized frost-date scheduling

Start planning free