Nasturtiums belong to a group of more than 80 perennial and annual species in the Tropaeolum genus, native to South and Central America and known for saturated, jewel-toned flowers. In most North American climates they are grown as annuals, planted after the last frost and blooming through the cool ends of the season. For many homeowners, the spring ritual that turns the yard back on runs through the same checklist, from grill maintenance and care to turning over the planting beds.
This article covers the types to choose, sun and soil requirements, direct-sowing steps, watering and feeding rules, container growing, and the pest and pruning routines that keep blooms coming. Nasturtiums are forgiving plants, which makes them a good first project and a reliable filler in established beds.
Nasturtium Types and How to Choose
There is a nasturtium variety for almost every purpose. Bushy, ground-hugging types fill bloom gaps in sunny perennial borders; trailing types spill over walls, edges, and containers; climbers add height against fences and trellises. The rounded leaves look like miniature lotus leaves, and both leaves and flowers are edible, with a peppery tang.
Bush Types for Borders and Beds
Bush nasturtiums stay compact, usually 12 to 18 inches tall, and work well as edging along paths and in the front of mixed beds. They bloom steadily through cool weather and slow down only when summer heat peaks.
Trailing and Climbing Types
Trailing varieties stretch several feet and are the classic choice for window boxes and the edges of raised planters. Climbers reach 6 to 10 feet when given a trellis or netting to climb.
Mature size spans a wide range, from 1 to 10 feet tall and 1 to 3 feet wide, depending on the variety. Bloom time runs from spring through summer, and in mild fall weather the plants flower again until frost.
Cool-Season Timing
Nasturtiums are cool-season annuals: they germinate quickly in cool soil, bloom through spring and fall, and slow down in high heat. In cold climates, the season extends on the other end with winter flowers for cold climates that carry color past the first frost.
- Border filler between perennials
- Edible garnish: leaves and flowers with a peppery bite
- Vegetable garden companion: attracts pollinators, deters aphids
- Quick cover for bare spots in new beds
| Type | Habit | Best use | Size |
|---|---|---|---|
| Bush | Compact mound | Borders, edging, beds | 12–18 in tall |
| Trailing | Sprawling stems | Containers, window boxes, walls | 2–4 ft spread |
| Climbing | Twining climber | Trellises, fences, netting | 6–10 ft tall |
Sun, Soil, and Planting Schedule
Nasturtiums want full sun in cool climates and tolerate light afternoon shade where summers run hot. They grow in almost any soil that drains, and they prefer a moist but well-drained bed with a pH anywhere from acidic to alkaline.
A simple soil test takes the guesswork out of amendments. Nasturtiums tolerate a wide pH range, so most garden soils need no adjustment; if the bed stays wet after rain, work in compost or coarse sand rather than lime or sulfur.
Soil That Drains
The most common failure is rich, wet soil. Fertile ground produces leaves at the expense of flowers, and soggy ground rots the roots. Average garden soil, improved with compost for drainage rather than fertility, gives the best bloom.
Planting After the Last Frost
Sow seeds directly in the garden after the threat of frost has passed. Seeds germinate in about 7 to 12 days once the soil warms to 55 to 65 degrees Fahrenheit, and the plants flower within 6 to 8 weeks. Fast and easy to grow from seed, nasturtiums are a dependable first crop for new gardeners.
Cool-Season Companions
Nasturtiums share the cool-weather window with cool-season grasses, which do their active growing in the same spring and fall temperatures. Planting them together keeps a border active at the ends of the season, when warm-season plants are still dormant or already fading.
- Choose a sunny spot with soil that drains.
- Sow seeds 1/2 to 1 inch deep, 10 to 12 inches apart.
- Water gently and keep the soil moist until seedlings appear.
- Thin seedlings so each plant has room to spread.
- Mulch lightly to hold moisture and keep roots cool.
Watering, Feeding, and Rainy-Season Care
Nasturtiums are drought-tolerant once established, but consistent moisture keeps the bloom going. Water deeply when the top inch of soil dries, and avoid overhead watering late in the day, which invites mildew on the rounded leaves.
Fertilizer: Less Is More
Skip high-nitrogen fertilizers. Rich soil pushes leaf growth and suppresses flowers. If the bed needs help, work a low-nitrogen fertilizer into the soil at planting time and stop there for the season.
Rainy Weather and Drainage
A wet spring is the hardest test. Saturated beds slow growth and rot roots, and the same drainage discipline that governs concreting in the rainy season, where surface water ruins a fresh pour, applies to a garden bed: water must move away from the root zone. Raise the bed, add organic matter, and avoid low spots.
| Symptom | Likely cause | Fix |
|---|---|---|
| Few flowers, many leaves | Rich or over-fertilized soil | Stop feeding, plant in leaner soil |
| Yellowing lower leaves | Overwatering or poor drainage | Let soil dry, improve drainage |
| Wilting in heat | Dry soil or hot afternoon sun | Water deeply, add shade |
| Mildew on leaves | Wet foliage, humid nights | Water at the base in the morning |
Growing Nasturtiums in Containers and Outdoor Rooms
Trailing nasturtiums are among the easiest plants for pots, window boxes, and hanging baskets. A single plant spills over the rim within weeks and keeps blooming until frost.
Container Selection
Choose a pot at least 8 to 10 inches across with drainage holes. Use a general-purpose potting mix and do not over-fertilize. Containers dry out faster than beds, so check moisture daily in warm weather.
Pot Size and Soil Mix
In a window box, space plants 6 to 8 inches apart. In a hanging basket, two or three plants fill a 12-inch basket. Mix perlite or coarse sand into the potting mix to guarantee drainage in pots that sit on solid surfaces.
Window boxes at ground level or above a porch railing both work, but boxes on the sunny side of the house bloom longest. Match the box depth to the variety: shallow boxes suit bush types, while trailing types need only enough depth for their roots, about 6 to 8 inches.
Pots Around Outdoor Living Spaces
A ring of containers turns a porch into a living room, the same way an outdoor fireplace transforms a covered porch into a four-season space. Nasturtiums add color at eye level beside seating areas, and the edible flowers make a handy garnish for outdoor meals.
- Check pots daily in summer heat
- Water until it runs from the drainage holes
- Feed monthly with a half-strength, low-nitrogen mix
- Move pots to shelter before hard frost
Companion Planting, Pests, and Keeping Blooms Coming
Nasturtiums are a popular companion plant in vegetable gardens because the flowers attract pollinating insects and the foliage draws aphids away from crops. The peppery leaves act as a trap crop that keeps pests off beans, cucumbers, and squash.
Common Pests and Simple Controls
Aphids are the main pest, clustering on the undersides of leaves and on new growth. A strong spray of water knocks them back, and insecticidal soap handles heavier infestations. Avoid broad-spectrum sprays, which kill the pollinators the flowers are meant to attract.
Bloom time responds to temperature, not day length. Plants stall when the mercury climbs into the 80s and resume flowering when nights cool again, so do not pull a tired plant in July; cut it back, water it, and wait for the September flush.
Deadheading and Pruning
Nasturtiums do not strictly need deadheading, but removing spent flowers keeps plants tidy and can extend bloom. Midseason, cut leggy stems back by a third to push fresh growth, and use the clippings in the kitchen since they are edible.
Tools That Make the Work Faster
Routine cutting and pinching go faster with sharp tools, and the same smart tool and equipment upgrades that extend a productive building season apply in the garden: good pruners, a reliable watering wand, and a comfortable kneeling pad change how long the chores take.
The whole season comes down to a short kit. The essential tools and equipment for the building season that every builder keeps on hand, pruners, a trowel, a watering can, and gloves, cover nearly every task a nasturtium bed demands. Choose the right types, plant after frost, keep the soil on the lean side, and the plants do the rest.