Best Friend in the Garden and Edible Flower: How to Grow Nasturtium From Seed

Nasturtiums are low-maintenance flowers on several of our gardening lists at Sow Right Seeds. Nasturtiums are edible, easy to grow from seed, and a great companion plant. Get to know nasturtium and start growing this friendly flower in your garden.

One of our easiest flowers to grow from seed, nasturtiums can be started indoors or directly sown outside after the last spring frost. For earlier spring blooms, start seeds indoors 2 to 4 weeks before the last spring frost date. 

Nasturtium seeds have a thick coat and will germinate quicker when soaked for 12 hours or by scarifying or nicking the seed.

• Use biodegradable pots to avoid root damage and transplant shock.

• Plant 2 to 3 nasturtium seeds per hole 1/2” deep in moist seed starting mix.

• Use a humidity dome to retain moisture until seeds sprout.

• Seeds will germinate in 7 to 14 days.

• Place grow lights close to the seedlings.

• Thin seedlings to the strongest plant after they have several sets of leaves and are 3” tall.

Once the danger of frost has passed, harden off seedlings before transplanting outdoors.

• Nasturtium is sensitive to transplanting, so direct sowing is recommended.

• Plant nasturtium seeds 1 to 2 weeks after the last spring frost.

• Soil temperature should be between 55º and 65ºF.

• You can continue to succession sow nasturtium seeds for several weeks.

• Plant seeds to a depth of 1/2” and 10 to 12” apart.

• Keep the soil moist until the plants are well established.

• Cover and protect young plants from frost. When fully grown, they can tolerate light frost but will die in freezing temperatures.

• Thin nasturtium plants after the seedlings have several sets of leaves and are 3" tall.

Nasturtium is so low-maintenance you can almost plant and forget about them. They thrive in full sun and well-draining soil without a lot of nutrients.

Nasturtium can be harvested and used in floral arrangements or as a beautiful and peppery garnish.

Cut nasturtium in the early morning for use in cut flower arrangements. Place in water, and the flowers will last about seven days. 

Nasturtium has a peppery taste, and the leaves, blossoms, and seed pods are all edible. You can harvest nasturtium leaves and flowers at any time. They add flavor and color to a variety of dishes.

If you are eating the seed pods, harvest them before they become mature and hard. The seeds can be pickled and used as a substitute for capers.

Wash harvested leaves and flowers before eating. Tasty, clean nasturtium plants are another reason to avoid fertilizers and pesticides.

Use sharp flower scissors to make clean cuts when harvesting or pruning nasturtium.

The nectar in nasturtium blossoms is very sweet, and hummingbirds love it. The shape and color of nasturtium flowers are also attractive to hummingbirds. Read here for more flowers that attract hummingbirds.

In gardening zones 9-11, nasturtium are perennials. When left to go to seed, nasturtium will self-seed. Otherwise, you will need to plant new seeds each year.