How-to Guide
How to Grow Nasturtiums
The short answer
Grow nasturtiums in poor to average, well-drained soil in full sun, and do not fertilize — they bloom best in low-nitrogen soils, and too much nitrogen gives leafy growth at the expense of flowers. Because they do not transplant well, direct-sow the large seeds into the garden after the danger of frost has passed.
The whole plant is edible: leaves and flowers have a spicy, peppery taste like watercress, and the buds and immature green seed pods can be pickled like capers.
Choose your form to fit the spot — trailing/climbing types (Tropaeolum majus) spill from pots and hanging baskets or climb a support, while bush types (Tropaeolum minus) stay compact mounds around 12 inches tall.
Poor soil on purpose
Nasturtiums break the usual rule that flowers want rich soil. University of Minnesota Extension notes they tolerate and bloom best in poor, low-nitrogen soils, because too much nitrogen drives leafy growth at the expense of flowers. If your nasturtiums are all foliage and no blooms, the soil is too rich — not too poor.
So skip the fertilizer and the compost-heavy bed. Give them full sun and well-drained soil, and let lean conditions do the work. This makes them useful for filling difficult, unimproved corners where fussier flowers sulk.
Water in dry spells, but otherwise the main task is restraint. Nasturtiums are also grown among vegetables as companion and trap plants, drawing aphids and cabbage pests away from the crop.
Sowing the big seeds
Nasturtium seeds are large and easy to handle, which makes them a classic first flower for children. Because the plants resent root disturbance, Illinois and Minnesota Extension both advise direct-sowing into the garden after the last frost rather than starting indoors and transplanting.
Poke the seeds in about half an inch to an inch deep where you want them to grow, water, and keep the soil moist until they sprout. In pots and baskets, sow a few seeds per container.
From there they are nearly hands-off — no staking for bush types, no feeding, just occasional water. Deadheading spent flowers keeps them blooming and tidy.
Edible parts and choosing a type
Every above-ground part is edible. The leaves and flowers carry a spicy, peppery flavor similar to watercress that brightens salads, and the flower buds and immature seed pods can be pickled to make a caper substitute. Harvest flowers and leaves young and use them fresh.
Pick the growth habit to match the job. Trailing types (Tropaeolum majus) can be left to spread as ground cover, spill over a wall or basket edge, or be trained up a trellis; bush types (Tropaeolum minus) form loose mounds around a foot tall for beds and edging.
For nasturtium sowing dates and vegetable-companion pairings, see the nasturtium planting calculator and companion pages.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- University of Minnesota Extension — Nasturtiums (Writers Guild) — Nasturtiums tolerate and bloom best in poor, low-nitrogen soils; too much nitrogen encourages leafy growth at the expense of flowers; leaves and flowers have a spicy, peppery taste similar to watercress; flower buds and immature seed pods are edible and likened to capers when pickled; there are bush types (around 12 inches) and trailing types for pots, walls, and trellises; grow best in full sun with well-drained soil.
- Illinois Extension — Nasturtium (Herbs) — Nasturtium does not transplant well, so it is suggested to direct-sow seeds into the garden after danger of frost has passed; trailing type (Tropaeolum majus) can climb or spread and bush type (Tropaeolum minus) forms loose mounds; leaves, flowers, buds, and immature seed pods are edible with a peppery flavor.