Cultivating Flora

How to Grow Nasturtium in Washington

Nasturtiums are vibrant, hardy plants that offer both beauty and utility in the garden. Known for their striking flowers and distinct round leaves, these plants are not only visually appealing but also edible. If you’re a gardener in Washington State looking to add some color and flavor to your garden, here’s a comprehensive guide on how to grow nasturtium successfully.

Understanding Nasturtium

Nasturtium (Tropaeolum majus) is native to South America and comes in various forms, including trailing and bush varieties. The flowers can be orange, yellow, or red, while the leaves are typically a lush green. One of the most significant benefits of nasturtiums is that they attract beneficial insects and repel harmful pests, making them an excellent addition to any vegetable or flower garden.

Varieties of Nasturtium

Before planting, it’s essential to choose the right variety of nasturtium for your space and aesthetic preferences. Here are some popular types:

Choosing the Right Location

Climate Considerations

Washington State has a diverse climate ranging from coastal maritime influences to inland continental weather patterns. Nasturtiums thrive in USDA hardiness zones 2-11, making them adaptable for most regions within Washington. However, pay attention to local microclimates that might affect sunlight availability and temperature.

Sunlight Requirements

Nasturtiums prefer full sun but can tolerate partial shade. In hotter areas of Washington, consider providing some afternoon shade to prevent wilting. Ensure that your chosen location gets at least six hours of direct sunlight daily for optimal growth.

Soil Preparation

Soil Type

Nasturtiums flourish in well-draining soil that is rich in organic matter. They prefer slightly acidic to neutral pH levels (around 6.0-7.0). Sandy loam is an excellent choice, but if you have clay soils, amending with compost can improve drainage.

Preparing the Soil

  1. Testing the Soil: Conduct a soil test to understand its nutrient content and pH level.
  2. Amending the Soil: Add compost or well-rotted manure to enhance nutrients and improve soil texture.
  3. Tilling: Loosen the soil up to 12 inches deep using a tiller or garden fork.

Planting Nasturtium

Seed Selection

Choose high-quality seeds from reputable nurseries or online suppliers. You can opt for traditional varieties or even hybrid selections that offer unique flower colors and characteristics.

Planting Time

In Washington, the best time to plant nasturtium seeds is after the last frost date, typically around mid-April to early May. For fall planting, sow seeds again in late summer.

Sowing Seeds

  1. Direct Sowing: Sow seeds directly into the prepared soil about 1 inch deep.
  2. Spacing: Space seeds approximately 10-12 inches apart for bush varieties and 12-24 inches apart for trailing types.
  3. Watering: Water gently after planting to settle the soil around the seeds.

Transplanting Seedlings

If you started your seeds indoors, transplant them outside once they have developed at least two sets of true leaves and when outdoor conditions are suitable. Be sure to harden off seedlings gradually by exposing them to outdoor conditions over a week.

Watering and Maintenance

Watering Needs

Nasturtiums do not require excessive watering; overwatering can lead to fungal diseases. Water them deeply but infrequently, allowing the top inch of soil to dry out between watering sessions.

Fertilizing

Nasturtiums thrive in low-nutrient soils as excessive fertilization can lead to more foliage growth at the expense of flowers. A light application of organic fertilizer during planting should suffice.

Pruning and Deadheading

Regular deadheading (removing spent flowers) encourages more blooms throughout the growing season. If plants become leggy, you can pinch back stems to promote bushier growth.

Pest Control and Diseases

Nasturtiums are relatively pest-resistant but can attract aphids and caterpillars. Here are some natural ways to manage pests:

Common diseases include downy mildew and root rot due to overwatering. To prevent these issues:

Harvesting Nasturtium

Edible Flowers and Leaves

Nasturtium flowers are not just lovely; they are also edible and add a peppery flavor similar to arugula in salads and garnishes. You can harvest flowers individually as they bloom or cut entire stems with both flowers and leaves for use in culinary dishes.

Seeds

The seeds of nasturtium can be harvested at maturity when they turn brown but before they fall from the plant. They can be pickled as a substitute for capers or dried for planting next season.

Preparing for Winter

In Washington’s milder climates, nasturtiums can survive winter if mulched adequately; however, in colder areas or where frost is severe, it’s recommended to treat them as annuals:

  1. Collect Seeds: Before frost hits, gather seeds from your healthiest plants for next season.
  2. Clearing Debris: Remove dead plant material from your garden bed to minimize disease risk during winter months.
  3. Mulching: Apply a layer of organic mulch around perennials (if applicable) to help insulate roots.

Conclusion

Growing nasturtiums in Washington is an enjoyable endeavor that enhances your garden’s aesthetic appeal while providing edible blooms that can be used in various dishes. With their vibrant colors and ease of care, nasturtiums make an excellent addition to any home garden—whether you’re a seasoned gardener or just starting out.

By following these guidelines on location selection, soil preparation, planting techniques, maintenance practices, pest control measures, harvesting methods, and winter preparation strategies, you will cultivate beautiful nasturtium plants that thrive in Washington’s diverse climate conditions. Embrace this delightful flower in your garden this season!