Nasturtium
Tropaeolum majus
Also known as: Indian cress, Tropaeolum, Garden nasturtium, Capucine, Mastuerzo
Quick facts
- Category
- herbs soft
- Difficulty
- beginner
- Days to harvest
- 50 to 75 days
- Harvest type
- continuous production over weeks or months
- Spacing
- 30 cm between plants
Environment
- Temperature
- 15–28°C
- pH
- 6 to 7.5
- EC (hydroponic)
- 1 to 1.6 mS/cm
- Daily light
- 14 to 22 mol/m²/day
Climate and zones
- USDA zones
- 9 to 11 (winter low around -7°C or warmer)
- Frost tolerance
- frost sensitive (dies at first frost)
- Season
- warm (summer crops, frost-sensitive)
Viable growing environments:
- outdoor year-round (in zone)
- outdoor in growing season (annual)
- unheated greenhouse / hoop house
- heated greenhouse
- indoor (heated home)
- indoor hydroponics under grow lights
USDA zone bounds reflect outdoor year-round survival. Anywhere outside the bounded zone range, this crop still grows as an annual in the warm months (outdoor_seasonal), under cover (greenhouse), or indoors under lights.
Growing systems
Nasturtium works in:
- media bed (ebb and flow)
- wicking bed
- soil bed
- drip / Dutch buckets
Growing media
The substrate the roots sit in. Choice depends on the system (clay pebbles don't fit NFT channels; rockwool isn't used in media beds) and the crop (nasturtium works in the media listed below).
| Medium | pH effect | Water retention | Bacterial surface |
|---|---|---|---|
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Soil-based mix (Potting soil) | varies by source | high | high |
Bacterial surface area matters for aquaponics: clay pebbles, lava rock, and pumice double as biofilter substrate. Low-surface media (rockwool, perlite, pea gravel) work in hydroponics but need a separate biofilter in aquaponics.
Nutrient demand by stage
NPK ratios are relative weights at each growth stage; the nutrient mix calculator scales them to absolute grams or ml. EC targets shift through the plant's life: seedlings need a much lighter solution than fruiting adults.
| Stage | N | P | K | EC target (mS/cm) |
|---|---|---|---|---|
| seedling | 1 | 1 | 1 | 0.5 |
| vegetative | 2 | 1 | 2 | 1.3 |
Aquaponics suitability
Compatible with typical aquaponics nutrient profiles. Fish waste provides enough nitrogen for healthy growth; supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.
Care notes
An easy, fast-growing plant for hydroponic systems, valued primarily for its edible flowers and peppery leaves. EC 1.0-1.5 mS/cm (deliberately low; rich conditions produce excessive leaf growth at the expense of flowers). pH 6.0-7.0. Temperature: 15–25°C (cool to moderate; heat above 30°C reduces flowering). Moderate light (DLI 14-20 mol/m2/day). DWC, media beds, or large containers. From seed to first flowers: 6-8 weeks. The flowers appear continuously for months once they start. Harvest flowers in the morning when they're freshly opened. The leaves are harvestable throughout growth. Under-feeding (low nitrogen) promotes flowering; overfed nasturtium produces lots of leaves and few flowers. For the pickled seed pod 'capers': harvest green, immature seed pods (before they harden) and pickle in salted white wine vinegar with peppercorns and bay. Bush varieties are better for contained hydroponic systems; trailing types work well in hanging baskets or cascading over the edge of media beds.
Verified against: rhs-uk, university-of-florida-ifas. Last reviewed 2026-05-15.