How to grow Nasturtium in the UK
Tropaeolum majus
Nasturtium (Tropaeolum majus) is a flower that grows well in UK gardens. Thrives on neglect — too much feed gives leaves not flowers. Trap crop for blackfly. This guide covers when and how to sow Nasturtium, the soil and position it likes, watering and feeding, companion planting, and when to harvest.
When to sow & grow Nasturtium
Sowing and harvest window through the year (UK):
Jan | Feb | Mar | Apr Sow | May Sow | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
Soil, position & care
- Soil
- Any reasonable, moisture-retentive but free-draining soil
- Soil pH
- 6.0–7.5
- Position
- Full sun, poor soil — rich soil gives leaves not flowers
- Sowing depth
- 1.5 cm
- Spacing
- 30 cm apart
- Sowing
- Sow direct Apr–May; trailing or bushy
- Growing
- A superb sacrificial trap crop for blackfly; edible peppery leaves and flowers
- Harvest & upkeep
- Pinch tips; deadhead
- Watch for
- Cabbage white caterpillars and blackfly (which is the point — it draws them off crops)
Companion planting for Nasturtium
Grows well with:
Grown as a sacrificial "trap crop" — blackfly and cabbage whites go for it instead of your beans and brassicas.
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Nasturtium FAQs
When should I sow Nasturtium in the UK?
In the UK, sow Nasturtium in April, May. Sowing across these months gives the plant the right soil temperature and day length to establish well.
What grows well with Nasturtium?
Nasturtium grows well alongside Apple, Aubergine, Blackcurrant, Broccoli, Brussels Sprout, Cabbage. Good companions can deter pests, attract pollinators or make better use of space.
How much sun does Nasturtium need?
Nasturtium prefers full sun (6+ hrs direct).
Is Nasturtium easy to grow?
Easy — good for beginners. Thrives on neglect — too much feed gives leaves not flowers. Trap crop for blackfly.