How to Grow Honesty
Lunaria annua
Honesty is a hardy biennial grown as much for its papery silver seed pods as for its purple spring flowers. Sow outdoors in early summer, let plants overwinter as leafy rosettes, and enjoy flowers the following spring. It tolerates partial shade — ideal for woodland edges and shady borders. No feeding needed; average soil suits it perfectly. Leave some plants to self-seed and you'll rarely need to sow again. Harvest stems once pods turn translucent, hang to dry, then rub off the outer casings to reveal the luminous silver discs.
When to Start
Direct sow outdoors as soon as soil reaches 5°C — typically early to mid spring. Can also be started indoors 4 weeks earlier for a head start.
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Growth Stages
Approximate days from start
Care Essentials
- Rarely needed. Thrives in average to poor soil — rich soil produces lush leafy growth at the expense of flowers and pods.
- Hardy biennial beloved for its papery silver seed pods used in dried flower arrangements. Tolerates partial shade and self-seeds freely. A brassica relative — rotate away from other brassicas to avoid clubroot.
Growing Conditions
- Min. soil temperature
- 5°C+
- Germination temperature
- 15–20°C
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- Sow indoors
- —
- Transplant out
- —
- First harvest
- —
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Spacing & Planting
| Plant spacing | 30 cm |
| Row spacing | 40 cm |
| Sow depth | 1 cm |
| Mature height | 75 cm |
| Mature spread | 30 cm |
Hardy biennial grown for its translucent silvery seed pods. Tolerates partial shade — good for woodland edges and shady borders. Self-seeds freely once established.
Pests & Diseases
Pest Caterpillars (Cabbage White)
Identification: Irregular holes in leaves, green or yellow caterpillars visible on foliage, frass (droppings) present on leaves
- Pick caterpillars off by hand
- Use fine mesh netting to exclude butterflies
- Apply Bacillus thuringiensis (Bt) biological spray
- Spray with a contact insecticide containing deltamethrin or lambda-cyhalothrin
Pest Aphids
Identification: Clusters of grey-green or black insects on shoot tips and undersides of leaves, causing distorted growth and sticky honeydew
- Blast off with a strong jet of water
- Spray with fatty acid-based insecticide
- Encourage ladybirds, lacewings and hoverflies
- Spray with a contact insecticide containing deltamethrin or lambda-cyhalothrin
Pest Slugs and Snails
Identification: Irregular holes in young leaves and slime trails around plants, worst in wet weather
- Use beer traps or copper tape barriers
- Apply organic slug pellets (ferric phosphate)
- Encourage natural predators such as hedgehogs and ground beetles
- Ferric phosphate-based pellets
Disease Clubroot
Symptoms: Plants wilt during the day and recover at night; roots become swollen and distorted; plants stunted and yellow
Treatment: No cure once infected — remove and destroy affected plants. Do not compost. Lime the soil to raise pH above 7.0 to discourage future outbreaks
Prevention: Rotate brassica-family plants on a minimum four-year cycle; avoid planting in waterlogged soil; raise transplants in modules to give them a strong start
Disease White Blister
Symptoms: Chalky white pustules on the undersides of leaves, with corresponding pale or distorted patches on upper surfaces; affected stems may become swollen and distorted
Treatment: Remove and destroy affected leaves and stems. Improve air circulation around plants
Prevention: Space plants well, avoid overhead watering, and rotate away from other brassica-family plants each year
Growing Conditions
| Min. soil temperature | 5°C |
| Germination temperature | 15–20°C |
| Base growth temperature | 4°C |
| Min. daylength to start | 9h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Honesty?
- Plant Honesty 30cm apart with 40cm between rows.
- When does Honesty flower?
- Honesty typically flowers approximately 60 days after transplanting.
- Is Honesty frost hardy?
- Honesty is classified as Hardy.
