Nasturtium
Tropaeolum majus · Garden Nasturtium · Indian Cress · Monks CressUSDA | Grow Zone
9-11Outdoors all year in zones 9 to 11. Anywhere colder, keep it as a houseplant. Protect it below 40°F.
- Light
- Full sun, 6 hours daily
- Water
- When top inch is dry
- Humidity
- Moderate, adaptable
- Temperature
- 60-75°F (15-24°C)
- Difficulty
- Beginner
- Growth
- Moderate
- Mature size
- 1-3 ft tall, 1-2 ft wide
Nasturtium, or Tropaeolum majus, is a vibrant annual known for its edible flowers and leaves. Native to South America, it adds beauty and flavor to gardens.
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Ideal temperature
60-75°F is where it grows fastest. Below 40°F cold damage starts.
Spacing and harvest
- Mature size
- 1-3 ft tall, 1-2 ft wide
- Plant apart
- 12-24 in
- Frost
- Half hardy: light frost only
Everything it needs
9 essentials at a glance
Watering
Nasturtiums prefer to be watered deeply but infrequently.
Water them when the top inch of soil feels dry, typically every 5-7 days during the growing season. In hot weather, they may require more frequent watering. Signs of over-watering include yellowing leaves and root rot, while under-watering can cause wilting and leaf drop.
Light
Nasturtiums thrive in full sun, requiring at least 6 hours of direct sunlight daily.
They can tolerate partial shade but may produce fewer flowers. Ideal placement includes sunny garden beds or containers that receive ample light throughout the day.
Soil
These plants prefer well-draining soil with a pH range of 6.0 to 7.0.
A mix of potting soil, compost, and sand or perlite is recommended for optimal drainage. Avoid heavy clay soils that retain moisture, as this can lead to root rot.
Humidity
Nasturtiums prefer moderate humidity levels but are quite adaptable.
To increase humidity, mist the leaves or place a humidifier nearby. Signs of low humidity include browning leaf edges and stunted growth.
Temperature
Nasturtiums thrive in temperatures between 60-75°F (15-24°C) and are hardy in USDA zones 9-11.
They can tolerate light frost but should be protected from extreme heat, which can cause wilting and flower drop.
Fertilizing
Use a balanced, water-soluble fertilizer with an NPK ratio of 10-10-10, applied every 4-6 weeks during the growing season.
Over-fertilization can lead to lush foliage with fewer flowers, while signs of nutrient deficiency include yellowing leaves and poor growth.
Pruning
Prune nasturtiums in late spring to encourage bushier growth and more blooms.
Use sharp, clean scissors to remove any dead or yellowing leaves. Deadheading spent flowers will promote continuous blooming throughout the season.
Repotting
Repot nasturtiums when they outgrow their container, typically every 1-2 years.
Choose a pot that is 1-2 inches larger in diameter. Signs that repotting is needed include roots growing out of the drainage holes and stunted growth. To repot, gently remove the plant from its current pot, loosen any tightly bound roots, and place it in fresh potting mix.
Propagation
Nasturtiums can be propagated by seeds or cuttings.
For seed propagation, plant seeds directly in the garden after the last frost, spacing them 10-12 inches apart. For cuttings, take 4-6 inch stem cuttings in spring, remove lower leaves, and place them in water or moist soil until roots develop.
When it's unhappy
Yellow leaves
Why it happens
Over-watering or nutrient deficiency.
How to fix it
Check soil moisture levels and adjust watering frequency. Fertilize if nutrient deficiency is suspected.
Wilting
Why it happens
Under-watering or extreme heat.
How to fix it
Water the plant thoroughly and provide shade during the hottest part of the day.
Powdery mildew
Why it happens
High humidity and poor air circulation.
How to fix it
Improve air circulation around the plant and apply a fungicide if necessary.
Root rot
Why it happens
Excess moisture and poor drainage.
How to fix it
Ensure proper drainage and reduce watering frequency. Remove affected roots and repot in fresh soil.
Pests (aphids, spider mites)
Why it happens
Attracts pests due to stress or poor health.
How to fix it
Inspect plants regularly, wash off pests with water, and use insecticidal soap if infestations occur.
Care through the year
Spring
In spring, sow seeds directly in the garden after the last frost. Ensure they receive full sun and water regularly as they establish.
Summer
During summer, monitor for pests and water more frequently in hot weather. Deadhead flowers to encourage continuous blooming.
Fall
In fall, continue to care for the plants until the first frost. You can collect seeds for next year's planting.
Winter
In winter, if grown in containers, bring nasturtiums indoors or protect them from frost. They are not frost-tolerant.
Toxicity & Safety
Nasturtiums are generally non-toxic to pets and children. However, ingestion of large quantities may cause mild stomach upset. The leaves and flowers are edible and often used in salads.
Good to know
Why are my nasturtium leaves turning yellow?
Yellow leaves on nasturtiums can indicate over-watering or a nutrient deficiency. Check the soil moisture and adjust your watering schedule accordingly.
How often should I water my nasturtiums?
Water nasturtiums when the top inch of soil feels dry, typically every 5-7 days. Adjust frequency based on weather conditions, especially during hot spells.
Can I grow nasturtiums in containers?
Yes, nasturtiums grow well in containers. Ensure the pot has good drainage and use a well-draining potting mix for best results.
Are nasturtiums edible?
Yes, both the leaves and flowers of nasturtiums are edible and have a peppery flavor, making them a great addition to salads and garnishes.
How do I encourage more blooms on my nasturtiums?
To promote more blooms, deadhead spent flowers regularly and avoid over-fertilizing, as too much nitrogen can lead to lush foliage with fewer flowers.
What pests should I watch for on my nasturtiums?
Common pests include aphids and spider mites. Regularly inspect your plants and treat infestations promptly to keep them healthy.
What is the best soil for growing nasturtiums?
Nasturtiums prefer well-draining soil with a pH of 6.0 to 7.0. A mix of potting soil, compost, and sand or perlite works well.
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