How to Grow Nasturtium

soil preparation

Nasturtium thrives in well-drained, fertile soil with a pH range of 6.0-7.0. Avoid overly rich soil, which encourages excessive leaf growth at the expense of flowers. Prepare your bed by loosening the top 8-10 inches with a garden fork, breaking up compacted soil. Mix in 1-2 inches of compost or aged manure to improve fertility and drainage. If your soil is heavy clay, add additional perlite or coarse sand (25-30% by volume) to ensure water doesn't pool around the roots. Level and rake smooth before planting. Nasturtium tolerates poor soils better than most plants, so don't over-amend—moderation yields more blooms and fewer leaves.

planting steps

watering

Nasturtium requires consistent moisture but not waterlogged soil. Water deeply to supply 1 inch per week during the growing season, including rainfall. In hot or dry periods, you may need to water 2-3 times weekly. Water at soil level in the morning to minimize leaf wetness and reduce disease risk. Use a soaker hose or drip irrigation for best results. Check soil moisture 2 inches below the surface: it should feel slightly moist, not soggy. Underwatered nasturtium shows wilting and reduced flowering; overwatered plants develop yellowed leaves and root rot. Reduce watering in fall as growth slows. Container-grown nasturtium dries faster; check pots daily and water when the top inch feels dry.

feeding & fertilizer

Nasturtium is a light feeder and actually flowers better in moderately fertile soil. At planting, work a balanced fertilizer (5-10-10 NPK or similar) into the soil at half strength—excessive nitrogen promotes leafy growth over flowers. After the first flowers appear (typically 35-52 days), apply a dilute liquid fertilizer (10-10-10 or 5-10-10) every 3-4 weeks if soil fertility is low. Container-grown nasturtium benefits from weekly dilute liquid feeding at half-strength. Avoid high-nitrogen fertilizers, which cause rampant vine growth and few flowers. Stop fertilizing in late summer to allow the plant to focus on flowering and seed production rather than new vegetative growth.

pruning & training

Nasturtium responds well to pinching and pruning. When seedlings are 6 inches tall, pinch off the growing tip to encourage branching and bushier, more floriferous growth. This step is optional but recommended for maximizing flower production. As the plant grows, remove any dead leaves or damaged stems. For trailing varieties, no pruning is necessary unless they outgrow their space. For climbing types, guide vines onto supports and remove stems that tangle or grow in unwanted directions. Pinching spent flower clusters doesn't extend bloom significantly (nasturtium flowers continuously), so focus pruning on shaping the plant's form. Hard pruning in midsummer can rejuvenate an overgrown plant and trigger a second flush of blooms.

storage & preservation

Nasturtium flowers and leaves are best used fresh and do not store well. Eat or prepare harvested flowers and leaves within a few hours of picking for best flavor and texture. Refrigerate in a damp paper towel inside a sealed container if you must store briefly (up to 2 days). Nasturtium seeds collected for next year should be left on the plant to fully mature (tan color), then harvested and dried completely in a warm, dry place for 2-3 weeks. Store dried seeds in a cool, dry location in an airtight container or paper envelope. Seeds remain viable for 3-4 years. Nasturtium leaves and flowers can be frozen in ice cubes with water for later use in cocktails or decoration, though this softens the texture significantly. For preservation, pickle immature seed pods using standard pickling brine—they keep for several months in the refrigerator or up to 1 year shelf-stable if processed using canning methods.

common mistakes to avoid

• ✗Over-fertilizing or planting in overly rich soil: This causes excessive leafy growth with few flowers. Use only moderately fertile soil and hold back on feeding. Correction: If this happens mid-season, stop fertilizing and water deeply to dilute excess nutrients.
• ✗Overcrowding plants: Spacing too close (less than 10-12 inches) causes poor air circulation, disease, and competition for water. Thin ruthlessly and maintain proper spacing from the start.
• ✗Planting in cold soil: Seeds will rot in soil below 60°F, and seedlings sulk if transplanted before warm weather. Wait for genuinely warm soil—patience prevents replanting.
• ✗Ignoring water consistency: Allowing the soil to dry out completely, then watering heavily creates stress and reduces flowering. Keep soil consistently moist but never soggy.
• ✗Planting in shade: Nasturtium needs full sun for maximum blooming. Partial shade (under 4-5 hours of direct sun) results in leggy growth and sparse flowers.
• ✗Forgetting the pinch: Skipping the early pinching step results in a single tall stem with flowers only at the top. Pinch seedlings at 6 inches to create a bushier, more floriferous plant.