Nasturtium brown leaf tips and edges: causes and what to do
6 results in the diagnosis tree begin with brown tips and edges, 3 of them marked likely when the answers fit. They are ordered here for Nasturtium (Tropaeolum majus), using what its sources say about humidity, soil moisture, cold tolerance and feeding and one problem recorded for it.
Sources last read 14 September 2026.
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. Wikipedia, CC BY-SA 4.0
Native range: as a cultigen from Peru (subtropical). Also sold as Brunnenkress, Common Nasturtium, Garden Nasturtium, greater Indian-cress, Indian cress and Mexican Cress.
What Nasturtium’s sources say that bears on this
- Humidity
- ASHRAE recommends indoor relative humidity between 30% and 60%Penn State Extension · read 13 September 2026
- Soil moisture
- Well-drainedRHS · read 13 September 2026
- Cold tolerance
- H3 — -5 to 1°CRHS · read 13 September 2026
- Feeding
- Feeding increases leaf growth but reduces flowering.NC State Extension · read 13 September 2026
How this shows up on a 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 Extension · read 13 September 2026Possible causes, likeliest first for a Nasturtium
Most likely too little water
Ranked higher because Nasturtium's recorded problems point this way.
Its source describes well-drained soil for this plant, so soil that dries between waterings is expected. The concern is soil left dry long enough for the plant to go limp or wrinkle.
- Well-drained RHS · read 13 September 2026
Why: Soil dry two inches down leaves the roots nothing to send up, and the leaf edges are the last tissue in line.
What to try:
- Water thoroughly, until it runs from the drainage hole.Useful: pot with drainage holes
- Check the soil with a finger every few days rather than watering on a fixed day.Useful: moisture meter
What would settle it: Water it thoroughly and watch the next new leaves. If they come in with clean edges under steadier watering, the edges were thirst.
Most likely cold
Ranked higher because Nasturtium's recorded problems point this way.
Its RHS hardiness rating puts this plant's cold floor at or below freezing, so cold damage in a heated room is unlikely. A frost outdoors, or a night in a cold car, is another matter.
- H3 — -5 to 1°C RHS · read 13 September 2026
Why: Soft, dark patches rather than crisp ones are damaged tissue rather than dried tissue.
What to try:
- Move it away from the glass at night, or keep the curtain on the room side of the nasturtium.
- Leave damaged leaves until new growth appears, then remove the worst of them.
What would settle it: Where the nasturtium sits at night, and what the glass feels like at that hour. Damage that appeared after one cold night, on the side facing the window, is the pattern.
Most likely a build-up of salts in the soil
- Chalk, Loam, Sand; pH Acid or Alkaline or Neutral RHS · read 13 September 2026
Why: Minerals from tap water and fertiliser are left behind as water evaporates, and a white crust on the compost or the pot rim is where they show.
What to try:
- Water slowly and heavily until several times the pot's volume has run through the drainage hole, to wash the salts out.Useful: pot with drainage holes
- Scrape off the top layer of crusted compost and replace it.
What would settle it: Scrape the crust. If it is gritty and dissolves in water it is mineral; if it is fluffy it is mould, which is a different problem.
Less likely for a Nasturtium, still possible
Questions
- What usually causes brown tips and edges on a Nasturtium?
- For Nasturtium: most likely too little water, most likely cold and most likely a build-up of salts in the soil. Its source describes well-drained soil for this plant, so soil that dries between waterings is expected. The concern is soil left dry long enough for the plant to go limp or wrinkle.
- How can I tell which one it is on my Nasturtium?
- Is the browning crisp and dry, or soft and dark? Crisp and dry; Soft and dark.
- What do Nasturtium's sources say about its soil moisture?
- RHS: Well-drained.
- What does this look like on a Nasturtium?
- 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. 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.
- Is Nasturtium safe to handle while I check it?
- Its sources list it as toxic to people. Wash your hands after handling the roots or sap, and keep trimmings away from pets.
Other plants that show brown tips and edges
African violetBrown tips on the newest leaves first
Barberton daisyEdges of the leaves brown while the middle stays sound
Bearded irisLeaf tips go crisp and brown
Bigleaf hydrangeaDry, bruised edges after a cold, windy spell
Bird of paradiseCrisp margins that appear in winter
Blue passion flowerDry, bruised edges after a cold, windy spell
Something else wrong with the Nasturtium?
What this does not cover
This page orders a decision tree's results using a plant's sourced care. It has not seen your plant, its pot or its window, and two problems at once are common: that is the usual reason a confident answer turns out wrong. The questions in the diagnosis tool narrow it further than a list can.