Growing Tips: Nasturtium

Quick Reference:

Annual, a plant that completes it’s life cycle in one season. Nasturtiums germinate best when the seed has been soaked for 24 hours in warm water, NO LONGER, plant seed immediately. Cover seed with 1/4 inch fine soil. Seed germinates in 10 to 14 days at an optimum soil temperature of 70 degrees F. Seed requires darkness to germinate. Ideal spacing in the garden is 8 to 10 inches. Do Not allow seed to freeze in storage. 

When and where to plant:

Nasturtiums are very sensitive to frost, like warm sandy soils, cool summer temperatures and prefer to be planted where they will remain all season. When transplanted care must taken not to disturb the roots. In Alaska plant seed directly in the garden after all danger of frost is past and the soil has warmed for mid to late summer bloom. For earlier bloom start seed indoors in small individual plastic pots, roots easily slide out of plastic, 4 to 5 weeks before the last frost. Fill pots that have drainage holes with a sterilized potting soil, soak seeds in warm water for 24 hours immediately before planting, no longer, to improve germination, plant 2 seeds per pot, cover them with 1/4 inch fine soil, seed requires DARKNESS to germinate and water well for good seed-soil contact. Cover pots with newspaper to help reduce evaporation and keep soil moist until seedlings emerge. Remove the cover as soon as the seedlings begin to sprout. When seedlings show their first green, water with a liquid solution of plant food, repeat every 2 weeks and place pots where the seedlings have full sun and cool nights until the garden is ready. Choose a garden location in full sun with a well drained, sandy soil; prepare soil and apply a moderate application of plant food. After all danger of frost is past, plant seed or transplant seedlings. To transplant seedlings make a hole in the soil twice the size the root ball, fill the hole with water, water transplants then carefully slide the moist root ball out of the plastic pot, place the seedling in the hole so the plant’s roots are the same depth in the soil and press the wet soil around the root ball. Immediately water well with a one-half strength solution of plant food to help reduce transplant shock.


Plants require very little care, provide ample water without allowing the ground to remain wet. Do not over fertilize, the plants will grow excessive foliage at the expense of flowers.