When to plant nasturtiums by city
Sow nasturtiums outdoors 1–3 weeks after your last frost, once the soil is at least 55°F. Here is what that means for 2027 in cities across the US, using each city’s average frost dates and the date its normal daily temperature reaches 55°F, so cool-spring places like Seattle wait for real warmth (NOAA 1991–2020). Pick the city with the climate most like yours, or enter your ZIP code above.
| City | Last frost | Sow outdoors |
|---|---|---|
| Seattle, WA (9a) | Mar 13 | May 1–15 |
| Portland, OR (8b) | Feb 25 | Apr 27 – May 11 |
| Sacramento, CA (9b) | Jan 12 | Mar 1–15 |
| Phoenix, AZ (10a) | Jan 5 | Jan 12–26 |
| Salt Lake City, UT (7b) | Mar 31 | Apr 22 – May 6 |
| Denver, CO (6a) | Apr 30 | May 7–21 |
| Dallas, TX (8b) | Mar 2 | Mar 9–23 |
| Minneapolis, MN (5a) | Apr 23 | May 6–20 |
| Kansas City, MO (6b) | Apr 4 | Apr 11–25 |
| Chicago, IL (6b) | Apr 10 | May 6–20 |
| Columbus, OH (6b) | Apr 20 | Apr 27 – May 11 |
| Nashville, TN (7b) | Apr 1 | Apr 8–22 |
| Atlanta, GA (8a) | Mar 24 | Mar 31 – Apr 14 |
| Raleigh, NC (8a) | Mar 28 | Apr 4–18 |
| Philadelphia, PA (7b) | Mar 30 | Apr 12–26 |
| Boston, MA (7a) | Apr 4 | May 5–19 |
In frost-free parts of Florida, southern California and the Gulf Coast, timing is about heat instead: plant nasturtiums in late winter or early spring and again in late summer.
Don’t go by the calendar alone. Nasturtiums planted into cold soil sit still for weeks; wait until the soil 4 inches down is at least 55°F and nights stay above 50°F.
Nasturtium spacing
In a square-foot bed, plant 1 per square foot. In traditional rows, space plants about 12 inches apart with 18 inches between rows.
Edible leaves and flowers. Aphids flock to it, sometimes sparing nearby crops.
How to grow nasturtiums
Nasturtiums are easy, fast annuals with round leaves and bright flowers, and every part above ground is edible with a peppery, watercress-like bite. Bush types make neat mounds for edges and containers, while trailing types climb fences or spill over walls. They bloom best with a little neglect.
Sun and soil
Full sun, with some afternoon shade in hot-summer areas. Poor to average, well-drained soil; rich soil and fertilizer produce lush leaves and few flowers.
Planting
- Soak seeds for a few hours or overnight to speed germination.
- Direct-sow ½ inch deep, 1–3 weeks after the last frost, once soil is about 55°F. Seeds need darkness to sprout and come up in 7–10 days.
- Space plants 12 inches apart in rows 18 inches apart.
- They dislike transplanting; if you start them indoors, use peat or paper pots 4–6 weeks before the last frost.
Care
- Skip fertilizer unless the soil is extremely poor.
- Water during long dry spells to keep plants blooming.
- Pick flowers or deadhead to prolong bloom until frost.
- Expect them to self-sow; pull unwanted seedlings in spring.
Harvest
Pick young leaves, which are milder than old ones, and flowers when fully open. Green seed pods can be pickled like capers. Harvest in the morning and use quickly; leaves and flowers wilt fast.
Common problems
- Aphids: Black aphids cluster on stems and leaf undersides. Hose them off, remove heavily infested stems, or use insecticidal soap.
- Imported cabbageworm: Green caterpillars chewing leaves. Hand-pick, or use Bt if plants are being stripped.
- Leafminers: Winding pale trails in leaves. Damage is cosmetic; remove affected leaves.
- Lots of leaves, few flowers: Too much fertilizer or too much shade. Stop feeding and move future plantings into more sun.
Varieties to try
- 'Empress of India' — compact, dark leaves, crimson flowers
- 'Alaska' — variegated leaves, mixed colors
- 'Jewel' mix — dwarf, flowers held above the leaves
- 'Jewel of Africa' — trailing, variegated, climbs to several feet
Crop rotation
Nasturtiums belong to the other families ().
Frequently asked questions
When should I plant nasturtiums?
What grows well with nasturtiums?
How far apart should I plant nasturtiums?
How long do nasturtiums take to grow?
Can nasturtiums handle frost?
Sources
- Frost dates: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020.
- Hardiness zones: 2023 USDA Plant Hardiness Zone Map, USDA-ARS and PRISM Climate Group, Oregon State University.
- Planting windows and spacing: Vegetable Planting Guide (GardenNotes #720), Colorado State University Extension, and other land-grant extension guides.
- Trap cropping: a review of the state of the art, Sarkar et al., 2018 (open-access review)
- Nasturtium, Tropaeolum species — University of Wisconsin–Madison Extension
- Tropaeolum majus (nasturtium) — NC State Extension Plant Toolbox