Nasturtium
Sources last read 14 September 2026.
Forgiving Among the more tolerant plants here.
Also called Brunnenkress, Common Nasturtium, Garden Nasturtium, greater Indian-cress, Indian cress, Mexican Cress, Monks Cress, Nose-Tweaker, Nose-Twister, Peruvian Cress and Watercress.
Nasturtium is toxic
What the sources say about its care
- Light
- Full sunRHS · read 13 September 2026
- Water
- Well-drainedRHS · read 13 September 2026
- Humidity
No source read publishes a humidity figure for any plant on this site. What follows is general guidance for foliage plants.
ASHRAE recommends indoor relative humidity between 30% and 60% 30–60%Penn State Extension · read 13 September 2026- Temperature
How cold this tolerates, not what it prefers. No source read for this site publishes a preferred range for a plant indoors.
H3 — -5 to 1°C -5 to 1 °CRHS · read 13 September 2026- Soil
- Chalk, Loam, Sand; pH Acid or Alkaline or NeutralRHS · read 13 September 2026
- Toxic to cats
- Listed as non-toxicASPCA · read 13 September 2026
- Toxic to dogs
- Listed as non-toxicASPCA · read 13 September 2026
- Harmful to people
- Can cause skin allergy. Use gloves and protective gear when handling it.RHS · read 13 September 2026
How it usually goes wrong
- Flowering stops while the foliage carries on
The nasturtium looks well in every other respect: green, firm and growing. What is missing is the flowering.
Buds are formed only when the plant has energy to spare. Its source places it in full sun, and in less light than that the surplus that pays for flowers is missing.
Telling it apart: The spacing of the newest leaves. Stretched growth means the light is short; normal spacing points at timing or feeding.
RHSDiagnose no flowers or dropped buds on this Nasturtium- Leaf tips go crisp and brown
A narrow dry border on the nasturtium, often with a faint yellow line against the healthy tissue. It appears on several leaves at once rather than spreading from one.
Heated air holds less water than the plant loses into it, so moisture leaves the leaf faster than it arrives. Penn State Extension cites ASHRAE's indoor range of 30% to 60% relative humidity, and winter heating often takes a room below it. That applies while it is grown indoors; its RHS rating of H3 describes a plant that also grows outside, where the air is seldom that dry.
Telling it apart: Look at the pot rim and the soil surface. A white crust points at a build-up from tap water or feed rather than at the air. Penn State also reports misting and pebble trays do little to the humidity around a plant.
Penn State ExtensionNasturtium brown leaf tips and edges: causes- The whole plant sags between waterings
The plant droops as a whole rather than losing particular leaves, and the soil surface has gone pale and hard.
Stored water is spent before the plant gives up anything else, and the tissue creases as it empties. Its source describes well-drained soil, which assumes the store is refilled.
Telling it apart: Lift the pot. A plant that is light and sagging is thirsty; one that is heavy and sagging is not.
RHSDiagnose drooping on this Nasturtium- Whitened areas where the sun falls longest
Scorched leaves on the nasturtium turn from pale to brown and brittle, and the damage stops where the shade of another leaf fell across it.
Nothing here disputes the full sun its source names. The damage comes from the change: foliage formed in lower light is thin, and a sudden move into direct sun bleaches it faster than tougher growth can replace it.
Telling it apart: Whether it followed a move or a season. Scorch appears within days of a change in position.
RHSDiagnose leaf drop on this Nasturtium
Not sure which it is? Ask the diagnosis questions for Nasturtium.
Routine care
- Feeding
- Feeding increases leaf growth but reduces flowering.NC State Extension · read 13 September 2026
- Propagation
- SeedNC State Extension · read 13 September 2026Increase from seed.RHS · read 13 September 2026
- Pruning
- Deadhead to extend flowering.RHS · read 13 September 2026
- Pests and diseases
- Can be troubled by aphids, whiteflies and mealybugs. Diseases: southern bacterial wilt.NC State Extension · read 13 September 2026Can be troubled by glasshouse red spider mite, glasshouse whitefly and whitefly. Diseases: virus diseases can occur.RHS · read 13 September 2026
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Photographs
About the plant
Tropaeolum majus, the garden nasturtium, nasturtium, Indian cress or monk's cress, is a species of flowering plant in the family Tropaeolaceae. An annual or a short-lived perennial with disc-shaped leaves and brilliant yellow, orange or red flowers, it is of cultivated, probably hybrid origin. It is not closely related to the genus Nasturtium.
From Wikipedia, CC BY-SA 4.0 · read 13 September 2026
- Native range
- as a cultigen from PeruWorld Checklist of Vascular Plants, June 2026 release, CC BY.Kew WCVP · read 13 September 2026Central and South AmericaNC State Extension · read 13 September 2026PeruRHS · read 13 September 2026
- Climate
- subtropicalWorld Checklist of Vascular Plants, June 2026 release, CC BY.Kew WCVP · read 13 September 2026
- Growth form
- annualWorld Checklist of Vascular Plants, June 2026 release, CC BY.Kew WCVP · read 13 September 2026Annual, Herb; habit climbing, clumping, moundingNC State Extension · read 13 September 2026Trailing (deciduous)RHS · read 13 September 2026
- Size
- Height 12–120 in; width 12–36 inNC State Extension · read 13 September 2026Height 1.5-2.5 metres; spread 1.5-2.5 metres after 1 yearRHS · read 13 September 2026
- Flowering
- Flowers gold/yellow, orange, pink, red/burgundy, white; blooms in fall, spring, summerNC State Extension · read 13 September 2026Flowers orange in summer and autumn; red in summer and autumn; yellow in summer and autumnRHS · read 13 September 2026
- Uses
What sources record people using this plant for. A traditional or medicinal use listed here is a record of use, not advice to eat it or treat anything with it.
Every part except the roots can be eaten; the taste is spicy.NC State Extension · read 13 September 2026
Common problems with Nasturtium
Plants with similar care
Blue passion flowerA thin dry rim that crumbles between the fingers
Bush lilyDry, curled edges on leaves near a heater
Dog roseEdges of the leaves brown while the middle stays sound
English lavenderBuds form and fall before they open
Flaming KatyA thin dry rim that crumbles between the fingers
Hardy fuchsiaBrown, papery patches on the leaves nearest the glass
Sources
- ASPCA · read 13 September 2026
- Kew WCVP · read 13 September 2026
- NC State Extension · read 13 September 2026
- Penn State Extension · read 13 September 2026
- RHS · read 13 September 2026
- Wikipedia · read 13 September 2026
What this does not cover
The figures above are what published sources say, not measurements of the plant in your room. They say nothing about your pot size, your water, the season, or how far from the glass the plant stands, and those decide more than any figure here does.
Humidity has no species figure because no source read for this site publishes one, and the only temperature published for this plant is a cold floor. The simulator fills those gaps with general figures for its kind of plant, marked as general and listed on how we read sources. Where a toxicity row says the plant was not assessed, that is the absence of a finding and not a finding of safety.
If something is already wrong, the diagnosis tool asks about the soil, the window and the watering, which is where the answer usually is.