Nasturtium
Also known as
Garden nasturtium, Indian cress, Monk's cress, Trailing nasturtium
Keep this plant’s care guide close at hand.
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Tropaeolum majus, commonly called nasturtium, is a fast-growing annual (or short-lived perennial in frost-free climates) prized for its rounded, shield-shaped leaves and spurred, funnel-shaped flowers in vivid oranges, yellows, reds, and creams. Stems trail or climb with support, making it excellent for groundcover, edging, hanging baskets, and trellises. Leaves and flowers are edible with a peppery, watercress-like bite; unripe seeds can be pickled as “poor man’s capers.” It thrives in lean, well-drained soil and blooms best when not overfertilized. Plants attract bees, butterflies, and hummingbirds and often serve as sacrificial trap crops for aphids, sparing nearby vegetables. Nasturtiums are frost-sensitive but tolerate variable conditions once established, frequently self-seeding to reappear in mild regions. Large seeds are easy to direct-sow after frost danger, germinating quickly in cool spring soils. Numerous compact bedding selections and vigorous climbing cultivars expand their garden uses, offering months of color with minimal care when given sufficient sun, moderate water, and good air circulation.
Taxonomy
Properties & Requirements
How to care for Nasturtium
Water
Keep soil evenly moist during establishment, then water deeply when the top 1–2 inches dry out. In-ground plants often succeed with weekly irrigation, though sandy soils may need more frequent watering. Containers dry faster—check daily in hot weather and water until excess drains. Avoid waterlogging, and do not let plants wilt repeatedly, which reduces flowering. Water at the base in the morning to limit foliar diseases such as powdery mildew. Mulch beds to moderate moisture and temperature.
Light
Full sun (6–8+ hours) produces the heaviest bloom and compact growth. In hot-summer regions, provide light afternoon shade or morning sun with filtered afternoon light to reduce heat stress. Indoors or on balconies, place in the brightest exposure—south or west windows—and rotate pots for even growth; supplemental LED lighting helps during short days. Too much shade leads to lanky stems, sparse flowering, and increased powdery mildew risk due to poor airflow.
Nutrients
Nasturtiums prefer lean soil; excess nitrogen encourages foliage at the expense of blooms. At planting, incorporate a modest amount of mature compost and avoid rich manures. In-ground plants typically require no further feeding. Container-grown specimens may benefit from a low-nitrogen, bloom-leaning liquid fertilizer (e.g., 2-4-4) at 1/4–1/2 strength every 3–4 weeks only if growth stalls. Rinse potting mix occasionally to prevent salt buildup, and stop fertilizing once flowering is abundant.
Temperature
Ideal growth occurs between 55–75°F (13–24°C). Seeds germinate best around 55–65°F (13–18°C). Light frost will kill or badly damage plants; sow after the last frost or protect with covers. In hot climates, flowering slows above 85–90°F (29–32°C); provide afternoon shade, steady moisture, and good airflow. In frost-free areas, nasturtiums can behave as short-lived perennials, blooming in the cool season. Avoid heat-reflective walls or pavement that intensify stress and hasten midsummer decline.
