How to Grow Nasturtiums from Seed: The Complete Guide

Nasturtiums are one of the most rewarding flowers you can grow from seed. They're fast, forgiving, brilliantly colorful — and every part of the plant is edible. Whether you're a first-time gardener or a seasoned grower, this complete guide covers everything you need to know about growing nasturtiums from seed, from soil prep to harvest.

Why Grow Nasturtiums from Seed?

Nasturtiums (Tropaeolum majus) are one of the easiest annual flowers to direct sow. They thrive in poor soil, require minimal fertilizer, and reward neglect with an explosion of color. Their edible flowers and leaves make them a favorite in kitchen gardens, cottage borders, and container plantings alike. Best of all, they grow quickly — most varieties bloom within 50–60 days of sowing.

When to Plant Nasturtium Seeds

Nasturtiums are frost-sensitive, so timing matters. Direct sow outdoors after your last frost date when soil temperatures reach at least 55°F (13°C). In most US growing zones, that means:

• Zones 3–5: Late May to early June
• Zones 6–7: Mid-April to early May
• Zones 8–10: March to April, or again in fall for a second flush

You can start nasturtiums indoors 2–4 weeks before your last frost, but they transplant poorly — use biodegradable pots to minimize root disturbance.

How to Direct Sow Nasturtium Seeds

Nasturtiums strongly prefer direct sowing. Here's how to do it right:

1. Choose your spot: Full sun to partial shade. They actually bloom better in lean, well-drained soil — avoid rich, heavily amended beds which encourage foliage over flowers.
2. Prepare the soil: Loosen to about 6 inches. No need to add compost or fertilizer.
3. Sow seeds: Plant seeds 1 inch deep, 6–12 inches apart (trailing/climbing types need more space). Seeds are large and easy to handle.
4. Water in: Keep soil evenly moist until germination, which typically occurs in 7–14 days.
5. Thin seedlings: Once established, thin to 12 inches apart for bushy types, 18–24 inches for trailing or climbing varieties.

Nasturtium Care Tips

• Watering: Water deeply but infrequently once established. Overwatering leads to lush leaves and few flowers.
• Fertilizing: Skip the nitrogen — it promotes leaves at the expense of blooms. If your soil is very poor, a light balanced fertilizer at planting is fine.
• Deadheading: Remove spent blooms to extend flowering through the season.
• Pests: Aphids love nasturtiums — which is actually useful! They act as a trap crop, drawing aphids away from vegetables. Knock aphids off with a strong spray of water.

Are Nasturtiums Edible?

Yes — and deliciously so. Every part of the nasturtium plant is edible:

• Flowers: Peppery, slightly sweet flavor. Use fresh in salads, as garnishes, or stuffed with soft cheese.
• Leaves: Spicy like watercress. Add to salads or use as a wrap.
• Seeds: Unripe green seeds can be pickled and used like capers.

All of our nasturtium varieties below are fully edible — no exceptions.

Our Edible Nasturtium Seed Varieties

We carry a curated selection of the best edible nasturtium varieties — from compact mounding types to sprawling trailers and climbers. Here are our top picks:

• Nasturtium Jewel Mix — A classic blend of red, orange, and yellow semi-double blooms on compact, mounding plants. Perfect for borders and containers.
• Nasturtium Alaska Mix — Stunning variegated foliage with cream-marbled leaves and bright mixed blooms. One of the most ornamental edible nasturtiums available.
• Nasturtium Whirlybird Cherry Rose — Upward-facing, spurless blooms in a rich cherry-rose tone. Excellent for showing off the full flower face in arrangements and salads.
• Nasturtium Melba Peach — Soft, creamy peach blooms with a delicate blush. A sophisticated choice for edible flower arrangements and cottage gardens.
• Nasturtium Baby Orange — Compact and prolific, with vivid orange blooms. Ideal for containers, window boxes, and small-space gardens.
• Nasturtium Tip Top Rose — A semi-double rose-toned variety with excellent heat tolerance and a long bloom season.

Browse our full nasturtium collection and more at Trailing Petunia – Shop All Flower Seeds.

Shop Our Nasturtium Seeds – Product Gallery

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Nasturtium Seed FAQs

Do nasturtium seeds need to be soaked before planting?

Soaking nasturtium seeds in warm water for 12–24 hours before planting can speed up germination, especially in cooler soils. It's not required, but it can shave a few days off your wait time.

How long do nasturtiums take to germinate?

Nasturtium seeds typically germinate in 7–14 days at soil temperatures of 55–65°F. Warmer soils speed things up; cooler soils slow germination down.

Can I grow nasturtiums in containers?

Absolutely. Compact varieties like Baby Orange and Jewel Mix are ideal for pots, window boxes, and hanging baskets. Use a well-draining potting mix and avoid overwatering.

Why are my nasturtiums not blooming?

The most common cause is too much nitrogen — either from rich soil or over-fertilizing. Nasturtiums bloom best in lean, well-drained soil. Too much shade can also reduce flowering.

Are nasturtium flowers safe to eat?

Yes! All of our nasturtium varieties are fully edible. The flowers have a peppery, slightly sweet flavor and are popular in salads, as garnishes, and stuffed as appetizers. Leaves and unripe seeds are also edible.

Do nasturtiums come back every year?

Nasturtiums are annuals in most climates (Zones 3–9). However, they self-seed prolifically — you'll often find volunteer seedlings returning year after year without replanting.

What is the difference between trailing and bush nasturtiums?

Bush or mounding types (like Jewel Mix and Baby Orange) stay compact at 12–18 inches and are ideal for borders and containers. Trailing types spread 3–6 feet and are great for covering slopes, spilling over walls, or climbing a trellis with support.

Related Reading

• Flower Seeds: The Complete Professional Growing Guide for Greenhouse & Garden Success
• Ultimate Guide to Growing Lisianthus and Other Flower Seeds for Florist-Quality Blooms
• Nasturtium Seeds 'Jewel Mix' – Colorful, Edible Flowers for Every Garden

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