Nasturtiums (Tropaeolum majus) are vibrant, easy-to-grow annuals that can brighten up any garden. Their colorful flowers and distinctive foliage make them a popular choice among gardeners. Whether you’re a beginner or an experienced gardener, growing and caring for nasturtiums can be an enjoyable experience. Here’s a comprehensive guide to help you cultivate and maintain healthy nasturtiums.
Choosing the Right Location
Nasturtiums thrive in full sun but can also tolerate partial shade. However, they bloom best with at least six hours of direct sunlight daily. Select a spot in your garden or on your balcony that gets plenty of sunlight, as this encourages the best growth and color in their flowers. The soil should be well-drained, as nasturtiums do not like “wet feet” (too much moisture around their roots). Sandy or loamy soil is ideal, but they are adaptable and can tolerate less-than-perfect soil conditions.
Soil Requirements
While nasturtiums are not fussy about soil, they perform best in slightly acidic to neutral soil (pH 6.1 to 7.5). They are relatively low-maintenance plants, and their roots do not require rich, fertile soil. In fact, over-fertilizing them can result in lush green foliage at the expense of flowers. If your soil is heavy or poorly draining, consider adding compost or well-rotted organic matter to improve its texture.
Planting Nasturtiums
Nasturtiums can be grown from seed or as nursery plants. Here’s how to plant them:
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From Seed: You can sow nasturtium seeds directly into your garden after the last frost, typically in early to mid-spring. For earlier blooms, start seeds indoors about 4-6 weeks before the last expected frost date. Soak seeds in warm water for a few hours before planting to encourage germination.
Plant the seeds about 1/2 inch deep and 10-12 inches apart. If you’re planting multiple rows, space them about 12 inches apart to allow for ample spreading. Nasturtiums can also be planted in containers for a more controlled environment.
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From Nursery Plants: If you prefer not to start from seeds, you can buy young nasturtium plants from a local nursery. Plant them at the same depth they were growing in their containers, and space them 10-12 inches apart.
Watering and Irrigation
Nasturtiums are somewhat drought-tolerant once established but prefer regular watering to keep the soil consistently moist, especially during dry spells. However, be cautious not to overwater. Overly moist soil can lead to root rot, a common issue in nasturtiums. It’s better to let the soil dry out slightly between waterings. A deep watering once a week is usually sufficient for most growing conditions.
For container-grown nasturtiums, ensure that your pots have drainage holes to prevent water from accumulating in the bottom, which can lead to waterlogged roots.
Fertilizing Nasturtiums
Nasturtiums do not require a lot of fertilizer. In fact, too much nitrogen can lead to an abundance of foliage with few flowers. It’s best to use a balanced, low-nitrogen fertilizer sparingly, if at all. A slow-release fertilizer at planting time is usually sufficient. If your soil is poor, adding organic compost before planting will help the plants grow without the need for additional chemical fertilizers.
Supporting Nasturtiums
Nasturtiums can be either compact or trailing, depending on the variety. Bush types tend to stay compact, while climbing or trailing varieties will need some form of support, like a trellis or a fence. If you’re planting nasturtiums along a garden bed or in hanging baskets, a trellis can provide a vertical element to showcase their vibrant flowers. Be sure to secure the vines gently as they grow to prevent breakage.
Pruning and Deadheading
Regular deadheading (removing spent flowers) encourages nasturtiums to produce more blooms throughout the growing season. This will help keep the plants looking tidy and vibrant. Pruning back leggy growth can also stimulate fresh growth, leading to fuller plants.
If you have trailing nasturtiums, you may need to trim back any long stems that begin to look untidy. This can help maintain the plant’s shape and prevent it from becoming too unruly.
Pest and Disease Control
Nasturtiums are generally resistant to most pests and diseases, but they can sometimes be affected by aphids, whiteflies, or caterpillars. These pests are easily controlled with insecticidal soap or by spraying the plants with a strong stream of water to dislodge them.
Powdery mildew can occasionally appear on nasturtiums, especially in humid conditions. To prevent this, ensure that the plants have good air circulation and avoid overhead watering, which can increase humidity around the plant. If powdery mildew does appear, remove affected leaves promptly, and treat with a fungicide or a homemade solution of water and baking soda.
Harvesting Nasturtium Flowers and Leaves
One of the best parts about growing nasturtiums is that both the flowers and leaves are edible, with a peppery flavor similar to arugula. You can harvest the leaves for use in salads, sandwiches, or as garnishes. Flowers make a colorful addition to salads or can be used to decorate cakes and desserts.
When harvesting flowers, pick them in the morning when they are fully open. Harvest leaves throughout the growing season by snipping them at the base of the stem. Don’t remove too many leaves at once, as this can stunt the plant’s growth.
Winter Care and Seed Saving
Nasturtiums are annuals, meaning they die off after one growing season. In colder climates, they won’t survive the winter, but in mild climates, they may self-seed and return the next year. If you’d like to save seeds for the following season, let some flowers go to seed. Once the seed pods mature and turn brown, you can collect them and store them in a cool, dry place until you’re ready to plant again.
For gardeners in colder regions, you can bring potted nasturtiums indoors before the first frost to extend their growing season or overwinter the plants in a sunny spot indoors.
Companion Planting with Nasturtiums
Nasturtiums are excellent companion plants because they attract beneficial insects, such as bees and ladybugs, while deterring harmful pests like aphids, whiteflies, and squash bugs. They are particularly well-suited to planting with vegetables like tomatoes, cucumbers, and peppers, as they can help protect these plants from pests.
Additionally, nasturtiums’ trailing vines act as a ground cover, helping to suppress weeds around other plants.
Common Nasturtium Varieties
Nasturtiums come in a variety of colors and forms. Some popular varieties include:
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‘Jewel Mix’: This variety includes a range of vibrant colors like red, orange, yellow, and cream.
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‘Tom Thumb’: A compact, bushy type of nasturtium that is ideal for smaller spaces.
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‘Creeping or Climbing Nasturtiums’: These varieties have long, trailing vines and are perfect for hanging baskets or trellises.
Conclusion
Growing and caring for nasturtiums is straightforward and rewarding. With their easy-growing nature, vibrant colors, and ability to attract beneficial insects, they make a fantastic addition to any garden. Whether you’re planting them in containers, hanging baskets, or garden beds, nasturtiums will bring beauty and utility to your garden throughout the growing season.