Nasturtium (Indian cress) care

Light

Nasturtium is a sun-lover and needs the brightest spot in the home to thrive. 6 hours of direct sun; tolerates light shade. Indoors that almost always means a south or west-facing windowsill in the northern hemisphere. Plants moved abruptly from low light to direct sun will scorch — acclimate them over 7-10 days by giving a little more sun each day.

Watering

Water nasturtium weekly watering. The actual day count varies with pot size, light level, and the season — the finger test (or, better, lifting the pot to feel its weight) is more reliable than a calendar. Empty any drainage saucer after watering so the pot is never sitting in water. Drought-tolerant once established; over-feeding produces leaf at expense of flowers.

Soil and pot

Nasturtium grows best in free-draining loam. pH 6.1-7.5. Lean soil produces more flowers. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Nasturtium sits happiest at around 40-70% (outdoor) humidity and 15-26°C (60-80°F). Outdoor humidity rarely matters. If you keep the room above 15 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed nasturtium sparingly. None needed; rich soil produces leaf at the expense of flowers. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on nasturtium in the Growli community. Each is annotated with the most common cause so you know where to start.

• All leaves, no flowers — Too rich soil or too much nitrogen.
• Cabbage caterpillars and aphids — Nasturtiums act as a trap crop — leave them and protect the brassicas behind.
• Slow germination — Soak seed overnight; soil must be warm.
• Trailing types take over — Pinch back tips to control.
• Frost damage — Tender; cut back at first frost.

Companion plants

Nasturtium pairs well with Cabbage, Tomato, Squash, and Cucumber. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Direct-sow after frost; soak seed overnight. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Nasturtium is pet-safe. Tropaeolum majus is not listed by the ASPCA. Considered safe and edible. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Nasturtium deep-dive guides

Every aspect of nasturtium care, each with its own calibrated guide:

• Nasturtium watering schedule
• Nasturtium light requirements
• Best soil mix for nasturtium
• Nasturtium fertilizing guide
• When to repot nasturtium
• How to propagate nasturtium
• Nasturtium growth rate & size
• Nasturtium cold hardiness
• Nasturtium temperature & humidity
• Is nasturtium toxic to cats & dogs?
• Getting nasturtium to bloom

Related guides

Nasturtium is also known as Indian cress, monk's cress, and garden nasturtium.

• Peace lily care — light, water and common problems
• Bird of paradise care — light, water and common problems
• Hoya care — light, water and common problems
• All 200 plant care guides in the Growli library