Alaska Nasturtium Flowers: Edible Blooms Thriving in Cold Climates

Growing Alaska nasturtiums means edible flowers that survive where most plants freeze—bright orange blooms that taste like peppery sunshine. 🌱 I planted mine last spring after years of struggling with tender varieties, and now they’re the first flowers to open in May and the last to fade in September.

Their cold tolerance makes them a game-changer for short-season gardens.

The secret to their success lies in their love for cool soil and full sun, even in Alaska’s brief summers. They thrive in well-draining soil—sandy loam works best—and need minimal fuss once established.

Water them when the top inch dries out, but don’t drown them; these hardy plants bounce back from neglect better than most annuals.

By midsummer, you’ll have a cascade of vibrant orange and yellow blooms that attract pollinators while repelling pests like squash bugs. Snip the flowers for salads or let them self-seed for next year’s garden. The more you prune, the bushier they grow—perfect for edging beds or spilling over containers.

Works in USDA Zones 3-9, making them ideal for northern gardens, high elevations, or early spring plantings. Pair them with peas, tomatoes, or cucumbers to keep pests at bay naturally. Once you try Alaska nasturtiums, you’ll wonder why you ever grew anything else in cold climates.

What you need

Step-by-step guide to growing Alaska nasturtiums in cold climates

Cold-hardy and vibrant, these edible flowers thrive where others falter.

Select the Alaska series specifically bred for cold tolerance—plants handle frost down to 20°F once established. Start seeds indoors 6-8 weeks before your last frost date or sow directly in cool soil when night temperatures dip to 40°F. I've found that direct sowing in early spring yields stronger plants because they adapt gradually to temperature shifts.

Use seed-starting trays with 2-3 inch deep cells filled with sterile seed-starting mix. Press seeds ¼ inch deep—they need light to germinate, so don't bury them too deeply. Keep the soil consistently moist but never soggy, as overwatering triggers damping-off in cold conditions.

Nasturtiums thrive in full sun to partial shade, but in Alaska's short growing season, prioritize at least 6 hours of direct sunlight daily. Plant in well-draining soil with a pH between 5.5 and 6.5—they tolerate poor soil but won't perform in waterlogged conditions. Amend heavy clay with 2-3 inches of compost before planting to improve drainage and fertility.

Space plants 8-12 inches apart in rows 12-18 inches apart to allow airflow and prevent fungal issues. Here's the thing—cold climates mean slower growth, so give them room to spread without crowding. If planting in containers, use 5-gallon pots for each plant, as nasturtiums develop extensive root systems.

Water deeply 2-3 times per week, aiming for 1 inch of water per week—more in extreme heat or wind. Nasturtiums are drought-tolerant once established, but consistent moisture during germination and early growth prevents leggy stems. Water at the base in the morning to allow foliage to dry before evening, reducing fungal risks.

Fertilize lightly with a balanced organic fertilizer (5-5-5) at planting and again when flowers appear. Too much nitrogen produces lush leaves at the expense of blooms. I've seen many gardeners overdo it—nasturtiums are light feeders. A handful of compost around each plant in early spring provides enough nutrients without risk of over-fertilization.

Deadhead spent flowers regularly to encourage more blooms, but leave some seed pods for self-seeding—this is how nasturtiums naturalize in cold climates. Pinch back leggy growth to promote bushier plants, especially after the first flush of blooms. You'll notice new side shoots forming within 7-10 days of pruning.

Harvest flowers and leaves as needed for culinary use, but don't take more than ⅓ of the plant at once. Nasturtiums regenerate quickly, but heavy harvesting weakens cold-hardy varieties. Leaves and flowers are both edible—toss them into salads or use as a peppery garnish. The Alaska series holds up well in cold frames for late-season harvests.

Protect young plants from late frosts with floating row covers or cloche tunnels. Once established, nasturtiums tolerate light frost, but new growth may suffer below 28°F. I've grown them successfully through Alaska winters in unheated cold frames—they go dormant but rebound in spring with minimal care.

In fall, allow plants to senesce naturally and self-seed. The resulting seedlings often overwinter and emerge earlier the next spring. Mulch with 2-3 inches of straw after the first hard frost to insulate roots. This simple step prevents heaving and keeps plants alive for next year's harvest.

Tips & tricks for perfect Alaska nasturtium cultivation

These cold-climate secrets will help you grow Alaska nasturtiums that thrive where others fail.

Variety Selection: The Alaska series stands out because it handles frost down to 20°F once established, but timing matters. If you're in a region with unpredictable spring temperatures, opt for direct sowing when night temps consistently stay above 40°F—this gradual adaptation creates stronger root systems. I've seen seedlings started too early in cold soil struggle, even with the Alaska variety.

Germination Conditions: When planting seeds in 2-3 inch deep cells, maintain soil moisture at 60-70% humidity during germination. Use a humidity dome or plastic wrap to create a mini greenhouse effect, but remove it immediately after sprouting to prevent damping-off. The ¼ inch depth is critical—any deeper and they won't get enough light to germinate properly.

Season Extension Strategy: For late-season harvests, use unheated cold frames after the first hard frost. The Alaska variety handles 28°F temperatures well, but new growth may suffer below that. I've successfully overwintered plants in cold frames by leaving them undisturbed—they go dormant but rebound spectacularly in spring with minimal care.

Fertilization Balance: Nasturtiums are light feeders, but timing matters. Apply that 5-5-5 organic fertilizer at planting and again when flowers appear—not before. Too much nitrogen early on produces lush foliage at the expense of those vibrant blooms we're after. A handful of compost around each plant provides enough nutrients without risk of over-fertilization.

Frequently asked questions

Can nasturtiums actually survive Alaska’s cold climate?

Alaska nasturtiums (Tropaeolum majus) are bred to thrive in cooler regions. While they prefer USDA Zones 3–9, they tolerate light frosts (down to 20°F/-7°C) if planted in well-draining soil and given afternoon sun. For extra protection, mulch around the base or grow them in containers to move indoors during harsh winters.

When is the best time to plant nasturtium seeds in Alaska?

Start seeds indoors 6–8 weeks before your last frost date (typically late April–early May in Alaska). Transplant seedlings outdoors after soil warms to 45°F (7°C), usually in late May or June. For direct sowing, wait until mid-June when nighttime temps stay above 50°F (10°C). Nasturtiums grow fast—expect blooms in 4–6 weeks!

Are all parts of the nasturtium edible, or just the flowers?

Yes! The flowers, leaves, and seed pods are all edible and packed with vitamin C, calcium, and peppery flavor. Use flowers as garnishes, leaves in salads, and young seed pods like capers. Note: Avoid overconsumption—nasturtiums contain glucosinolates, which may irritate sensitive stomachs in large amounts. Always harvest organic plants!

Why aren’t my nasturtiums blooming in Alaska’s short growing season?

Several factors might slow blooms: lack of sun (they need 6+ hours daily), overcrowding (thin seedlings to 10–12 inches apart), or nutrient deficiencies (feed with balanced fertilizer every 4–6 weeks). Pinch back leggy stems to encourage bushier growth. If days are too short, try grow lights or choose dwarf varieties like ‘Alaska’ for earlier flowers.

What’s a cold-hardy alternative to nasturtiums for Alaska gardens?

If nasturtiums struggle, try these edible, cold-tolerant flowers:

• Calendula (Calendula officinalis) – Thrives in Zones 3–10, edible petals, and pest-repellent.
• Borage (Borago officinalis) – Survives light frosts, blue flowers, and cucumber-flavored leaves.
• Violas (Viola × wittrockiana) – Hardy to 10°F (-12°C), sweet-tasting blooms.
• Sweet Alyssum (Lobularia maritima) – Cold-resistant, honey-scented, and attracts pollinators.

Wrapping up and next steps

Alaska’s nasturtium flowers prove that beauty and edibility can thrive even in chilly climates! Whether you’re a gardener looking to expand your harvest or a foodie eager to explore unique flavors, these vibrant blooms offer a delicious and versatile addition to your table.

With their hardy nature and easy care, they’re perfect for beginners and seasoned growers alike.

Ready to bring Alaska nasturtiums into your garden or kitchen? Start small—plant a few seeds or snip a bouquet from your local greenhouse—and let their bold flavors inspire your next culinary adventure! 🌱