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How to Grow Nasturtium: A Comprehensive Guide to Planting and Care

Published on
February 28, 2025
How to Grow Nasturtium: A Comprehensive Guide to Planting and Care
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Easy Houseplants Q&A

Why is there a white, crusty buildup on the surface of my plant's soil?

This is a very common issue for indoor house plants. Usually, it is a buildup of soluble salts and minerals from tap water or fertilizer. If it looks soft and fuzzy rather than hard and crystalline, it might be a harmless saprophytic fungus breaking down organic matter in the soil. To fix mineral crusts, scrape off the top layer of soil and occasionally "flush" the pot by pouring distilled water through it until it runs out the bottom freely.

Do easy houseplants need fertilizer to survive?

They will survive without it, but they won't thrive. In nature, plants get a constant supply of nutrients. In a pot, they eventually deplete the soil. Using a standard houseplant fertilizer at half-strength during the spring and summer will encourage stronger roots and larger leaves. Do not fertilize in winter when the plants are dormant.

How do I know if my plant is getting the right amount of light?

If a plant is getting too much direct light, its leaves will look bleached, washed out, or develop crispy, scorched brown patches. If it isn't getting enough light, the growth will be "leggy" (long stems with large gaps between leaves), variegated plants will lose their patterns and turn solid green, and the soil will take weeks to dry out, increasing the risk of root rot.

Rooftop Garden Design And Roof Garden Ideas For Your Terrace

What is the most important step before transforming your rooftop into a garden?

The most critical step is hiring a structural engineer to assess the load-bearing capacity of your roof surface. Soil, water, and containers are incredibly heavy, and ignoring weight restrictions can lead to catastrophic structural damage. Additionally, you must verify all local laws to ensure compliance.

How do I manage regular watering during hot weather and dry spells?

Because the sun and wind dry out elevated pots rapidly, hand-watering becomes exhausting. The best solution is to install a drip irrigation system with automated irrigation lines to ensure consistent moisture. Using a self-watering pot or adding vermiculite and coir to your soil mix will also help retain water during a dry spell.

What kind of soil mix should I use for growing plants in containers on a roof terrace?

Never use standard garden dirt, as it is too heavy and compacts easily. Instead, use a lightweight potting soil that includes a balanced mix of loam for structure, coir for moisture retention, and vermiculite for aeration. Enrich this base with organic compost and worm castings to provide nutrients.

Balcony Gardening Q&A

Q: Do I need a lot of direct sunlight per day to start a balcony garden?

A: No. While cherry tomatoes need 6-8 hours of direct sunlight per day, leafy greens and herbs like parsley or chive thrive in partial shade. Simply choose the right plants for your specific amount of sun.

Q: Can I use standard garden soil in my balcony pots?

A: No. Standard garden soil is too heavy and compacts easily. Always use a high-quality, well-draining potting soil mixed with peat moss and compost for your container garden.

Q: How often should I be watering my plants on a balcony or rooftop?

A: Check daily. Stick your finger an inch into the soil; if it is dry, it is time to water. Container plants dry out quickly, so ensure pots have holes in the bottom and consider self-watering pots for convenience.

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infographics about how to plant nasturtium a step by step guide

Nasturtiums are delightful, easy-to-grow plants that bring vibrant colors and edible flowers to any garden. Whether you're growing nasturtiums in containers, hanging baskets, or directly in the garden, these bushy plants are popular for their low maintenance and peppery taste. I first discovered their charm when I planted a few seeds in a sunny corner of my backyard. Their cheerful blooms not only added a burst of orange and yellow but also attracted beneficial insects like ladybugs and bees, making my garden buzz with life. Their peppery leaves were a surprising addition to salads, adding a fresh kick that my family enjoyed. Let's dive into this comprehensive guide to learn more about planting, growing, and caring for these versatile plants.

Basics of Nasturtiums

Nasturtiums (Tropaeolum majus) are known for their bright, trumpet-shaped flowers and attractive foliage. These plants are valued not only for their aesthetic appeal but also for their culinary and medicinal uses.

Nasturtium Plant Profile

Plant Attribute Details
Plant Name Nasturtium (Tropaeolum majus)
Plant Type Annual (sometimes grown as perennials in frost-free climates)
Size Typically 1 to 10 feet in length, depending on the variety
Soil Type Well-drained, poor to average soil
Soil pH Slightly acidic to neutral (6.1 to 7.8)
Bloom Time Late spring to early fall
Hardiness Zones 9-11 (grown as annuals in cooler climates)
Native Area South America
Toxicity Level Non-toxic to humans and pets

Best Types of Nasturtiums

There are several types of nasturtiums, each with unique characteristics. Here are some popular varieties:

Jewel Mix

This variety is perfect for gardeners seeking compact plants bursting with vibrant, double flowers in shades of red, orange, and yellow. Jewel Mix nasturtiums are excellent for small gardens or containers, where their prolific blooms create a cheerful display throughout the growing season. They thrive in full sun and well-drained soil, making them a low-maintenance choice for gardeners looking to add intense color to their outdoor spaces.

Empress of India

Known for its striking deep crimson flowers against dark green foliage, Empress of India nasturtiums are ideal for gardeners aiming to create bold borders or focal points in their garden beds. This variety's compact growth habit makes it perfect for edging pathways or defining garden borders with a regal touch. They prefer rich, well-draining soil and benefit from regular watering to maintain their lush appearance and vibrant blooms.

Alaska

Alaska nasturtiums feature variegated leaves paired with a mix of vibrant flower colors, making them a favorite among gardeners looking to add visual interest to containers or small garden spaces. Their versatile nature allows them to thrive in both sun and partial shade, making them suitable for various garden settings. Alaska nasturtiums are easy to grow from seed and offer a charming blend of foliage and flowers that brighten any garden corner or balcony.

Trailing Nasturtiums

Gardeners who enjoy vertical gardening or want to add a cascading element to their outdoor spaces will appreciate trailing nasturtiums. These varieties produce long vines that gracefully spill over edges of hanging baskets, trellises, or garden walls. Their abundant flowers and trailing growth habit create a lush, flowing effect that enhances the beauty of any garden setting. Trailing nasturtiums prefer full sun and well-drained soil, thriving with regular watering to support their vigorous growth and continuous flowering.

Dwarf Nasturtiums

Perfect for small gardens, patio containers, or even window boxes, dwarf nasturtiums offer compact growth and vibrant blooms in a manageable size. These plants are well-suited for gardeners with limited space who still want to enjoy the beauty of nasturtiums. Dwarf varieties bloom prolifically in full sun and well-drained soil, requiring minimal care beyond regular watering and occasional deadheading to encourage continuous flowering throughout the season.

When and Where to Plant Nasturtiums

Nasturtiums are versatile and can be planted directly in the garden or started indoors. They prefer full sun but can tolerate partial shade, especially in hotter climates.

Timing

Sow seeds directly in the garden after the last frost date. In warmer climates, you can start seeds indoors 4-6 weeks before the last frost.

Location

Choose a location with well-drained soil and plenty of sunlight. Nasturtiums do well in garden beds, borders, containers, and hanging baskets.

Nasturtium Planting Guide

closeup of a nasturtium flower

Whether you're a beginner or a seasoned gardener, growing nasturtiums is easy and adds a splash of color to your garden beds or containers. Here's a step-by-step guide to help you get started.

Prepare the Soil

Choose a sunny to partially shaded location with well-draining soil that has a moderate fertility level, ideally with a pH between 6.0 to 7.5. If necessary, amend the soil with compost or organic matter to enhance drainage and fertility for optimal growth.

Planting Depth

When planting nasturtium seeds, sow them approximately 1 inch (2.5 cm) deep into the soil. For transplanting seedlings, ensure they are set at the same depth they were growing in their nursery containers to facilitate healthy root development.

Spacing

Space nasturtium seeds or seedlings about 10 to 12 inches (25 to 30 cm) apart. This spacing provides enough room for the plants to spread and grow without overcrowding, promoting better airflow and reducing the risk of disease.

Support (if needed)

For climbing varieties, provide support such as trellises or stakes to help them grow upright. Trailing varieties can benefit from being planted near edges or allowed to spill over garden beds or containers for a cascading effect.

Requirements for Growing Nasturtiums

Requirements for Growing Nasturtiums infogprahics

Growing nasturtiums is quite straightforward and they're known for their bright, cheerful flowers and edible leaves. Here are the basic requirements for growing nasturtiums:

Soil

Nasturtiums prefer well-drained, poor to average soil. They thrive in soil that is not overly fertile, as too much nitrogen can lead to excessive foliage growth instead of flowers. Avoid heavy fertilization.

Water

Keep the soil consistently moist, especially during dry periods. Water at the base of the plant to prevent fungal diseases. Ensure the soil doesn't dry out completely between watering sessions.

Temperature and Humidity

Nasturtiums grow best in temperatures between 55°F and 75°F (13°C to 24°C). They can tolerate higher temperatures, but in hotter climates, they may need more frequent watering to thrive. Moderate humidity levels are generally suitable.

Sunlight and Location

Nasturtiums thrive in full sun to partial shade. In hot climates, providing some afternoon shade can prevent the leaves from scorching. Ensure they receive at least 4-6 hours of sunlight daily for optimal growth and flowering.

Maintenance Tips for Nasturtiums

infographics about maintenance tips for nasturtiums

Maintaining nasturtiums is relatively easy once they are established. Here are some maintenance tips to keep your nasturtiums healthy and thriving:

Fertilizer

Nasturtiums prefer nutrient-poor soil. Avoid using fertilizer, as excessive nutrients can result in lush foliage at the expense of flowers. This plant thrives in less fertile conditions, producing more vibrant blooms.

Pruning

To encourage continuous blooming, regularly deadhead spent flowers by pinching or cutting them off at the base of the stem. Additionally, trim back overgrown plants as needed to maintain their shape and size throughout the growing season.

Mulching

Apply a light layer of organic mulch around nasturtium plants to help retain soil moisture, regulate soil temperature, and suppress weed growth. However, avoid heavy mulching directly around the stems, as it can lead to moisture retention and potential root rot issues.

Potting and Repotting

When growing nasturtiums in containers, use a well-draining potting mix to prevent waterlogging. Ensure the container has adequate drainage holes. Repot the plants into larger containers if they outgrow their current pots or if root-bound, typically every 1-2 years.

Transplanting

If starting nasturtiums indoors, transplant seedlings outdoors after the danger of frost has passed, typically in spring. Choose a location with full sun or partial shade. Space seedlings 10-12 inches apart to allow for optimal air circulation and growth.

Overwintering

In regions with frost, treat nasturtiums as annuals, as they are sensitive to freezing temperatures. Alternatively, in warmer climates, they can survive the winter months if provided with some frost protection, such as covering them with a cloth during cold spells or planting them in a sheltered location.

Common Pests and Diseases

Nasturtiums are relatively pest-resistant but can occasionally suffer from the following:

Aphids

Aphids are small, soft-bodied insects that suck sap from leaves and stems. They can be controlled by using insecticidal soap or by spraying with water to wash them off. Encouraging natural predators like ladybugs or lacewings can also help manage aphid populations.

a pair of aphids closeup photo credit from sascha kohlmann

Caterpillars

Caterpillars are larvae of butterflies and moths that can chew on nasturtium leaves, causing visible damage. They can be managed by handpicking when spotted. For severe infestations, organic insecticides such as neem oil or Bacillus thuringiensis (Bt) can be used.

closeup of caterpillar on a branch

Leaf Miners

Leaf miners are larvae that live and feed within leaf tissue, creating tunnels or mines. To control leaf miners, promptly remove and destroy affected leaves. Pruning away heavily infested areas and improving overall plant health can reduce susceptibility.

leaf miners on a large leaf credit from martin labar

Powdery Mildew

Powdery mildew is a fungal disease that manifests as white powdery spots on nasturtium leaves. It thrives in humid conditions with poor air circulation. Control measures include improving air circulation around plants by proper spacing, avoiding overhead watering, and applying fungicidal sprays if necessary. Sprays should be applied early in the morning or late in the evening for best effectiveness.

powdery mildew close-up on a leaf

Preventing and Treating Issues

Practicing these prevention and treatment methods, you can maintain healthier nasturtium plants and address issues promptly to minimize damage.

Prevention

Regularly inspecting nasturtium plants is crucial for early detection of pests and diseases. Maintain good garden hygiene by removing debris and weeds that can harbor pests. Companion planting with plants that repel pests, such as marigolds or garlic, can help deter insect infestations naturally.

Treatment

If issues arise despite preventive measures, consider using organic treatments such as neem oil or insecticidal soap to manage pests like aphids or caterpillars effectively. Handpick and remove infected plant parts promptly to prevent the spread of diseases like powdery mildew. Proper disposal of infected plant material helps reduce the likelihood of further outbreaks.

Harvesting Nasturtiums

man harvesting nasturtium in a field outdoors

Nasturtium flowers, leaves, and seeds are all edible and can be harvested for culinary use.

Flowers: When harvesting nasturtium flowers, choose ones that are fully open and free from damage or discoloration. This ensures they are at their peak flavor and appearance. Nasturtium flowers have a peppery taste that complements salads, sandwiches, and various dishes. They can also be used creatively as decorative garnishes or infused into vinegars for added flavor. Harvest flowers as needed to keep plants producing new blooms throughout the season.

Leaves: For nasturtium leaves, opt for young and tender ones when harvesting for salads. These leaves offer a mild, peppery flavor similar to arugula, making them ideal for fresh dishes. Older leaves can be harvested as well, although their flavor intensifies, making them better suited for cooking. Use nasturtium leaves chopped in salads, blended into pesto, added to soups for a peppery kick, or incorporated into stir-fries for a unique taste profile.

Seeds: Harvest nasturtium seeds once the flowers have faded and the seed pods have matured. Look for pods that are dry and turning brown, indicating that the seeds inside are fully developed. Allow these pods to dry further in a warm, dry location for about a week. Once dried, carefully remove the seeds from the pods and store them in a cool, dark place. Nasturtium seeds can be pickled as a substitute for capers or saved for planting in the next growing season. Properly dried seeds ensure viability and successful germination when planted.

Frequently Asked Questions:

Q: Are nasturtium flowers edible?

A: Yes, nasturtium flowers have a peppery taste and can be used in salads or as a garnish.

Q: How do I grow trailing nasturtium varieties?

A: Trailing nasturtium varieties are ideal for hanging baskets. Plant them in hanging containers with well-drained soil and full sun exposure.

Q: What are some companion plants for nasturtiums?

A: Nasturtiums are beneficial for companion planting with vegetables like tomatoes and cucumbers, as they can deter pests like aphids.

Q: Can I sow nasturtium seeds indoors?

A: Yes, you can start nasturtium seeds indoors 4 to 6 weeks before the last spring frost. Transplant seedlings outdoors after the danger of frost has passed.

Q: Can I grow nasturtiums in hanging baskets?

A: Yes, trailing varieties of nasturtiums are ideal for hanging baskets. They create a beautiful cascading effect with their vibrant flowers and foliage.

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