Nasturtium
Garden Nasturtium, Tropaeolum, Indian Cress, Monks Cress
Edible ornamental — flowers, leaves, and seed pods are all edible with a peppery flavor. Excellent trap crop for aphids; plant near brassicas and cucurbits to lure aphids away. Thrives in poor, dry soil — rich soil promotes foliage over flowers. Direct sow after last frost; large seeds germinate quickly. Trailing varieties ideal for hanging baskets and covering bare soil. Self-seeds reliably.
- Germination
- 7–14 days
- Soil temperature
- 13–18 °C
- Harvest after sowing
- 35–60 days
- Spacing
- 20–30 cm
When to plant nasturtium
Sow outdoors from 2 weeks before to 1 week after your last spring frost.
Dashed line: typical last spring frost in zone 7 (Apr 5). Zone dates are averages; most of the UK is zone 8–9, central Europe 6–7 and the Baltics and Scandinavia 4–6. In the app, Tomatograph uses your garden's own frost dates.
How to grow nasturtium
- 1
Sow
Sow the large seeds 1 cm deep around the last frost, where they are to flower. They come up in 7–14 days.
- 2
Keep the soil lean
Poor, dry soil gives the most flowers; rich soil gives mostly leaves.
- 3
Use as a trap crop
Aphids love nasturtiums. Plant them near brassicas and squash to draw aphids away.
- 4
Harvest
Flowers, leaves and green seed pods are all edible with a peppery taste, from about 35 days. Trailing types cover bare soil and spill from pots.
Growing conditions
Light
Full sun
Water
Low water
Temperature
10–30 °C
Frost tolerance
Frost-sensitive — protect below 0 °C
Days to maturity
35–55 days
How Tomatograph watches your nasturtium
Tomatograph checks your local forecast every morning and only speaks up when one of these applies to your garden.
- Forecast of 2 °C or lowerFrost alert the evening before: cover plants with fleece or bring pots inside.
- 3 days at 35 °C or aboveHeat-wave alert while plants are flowering or fruiting: shade and water early.
- Humidity above 80% for 48 hoursCheck for powdery mildew, which thrives in those conditions.
- Within a week of maturityHarvest-window reminder based on when you planted.
Nasturtium questions
- When should I plant nasturtium?
- Sow outdoors from 2 weeks before to 1 week after your last spring frost.
- How long do nasturtium seeds take to germinate?
- Usually 7–14 days at a soil temperature of 13–18 °C.
- How long until I can harvest nasturtium?
- About 35–60 days after sowing, depending on variety and weather.
- How far apart should I plant nasturtium?
- Allow 20–30 cm between plants.
- What grows well with nasturtium?
- Good neighbours include cucumber, squash, beans, broccoli.
Growing guide written by Tomatograph. Planting figures from openplantdb (CC0 1.0). Zone frost dates are averages from openplantdb (CC0 1.0).