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When to Plant Nasturtium in South Dakota

Nasturtium (Tropaeolum majus) is a fast-growing annual with distinctive round, lily-pad leaves and bold trumpet-shaped blooms in warm oranges, reds, and yellows. Both the flowers and leaves are edible with a peppery watercress flavor. Planted near vegetables, nasturtiums act as a sacrifice trap-crop, luring aphids away from more valuable plants. They thrive in poor, dry soil — rich conditions produce lush foliage but few flowers.

South Dakota spans USDA hardiness zones 4a, 4b, 5a (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

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Find Your County

Click your county for exact Nasturtium planting dates based on your local frost dates.

Nasturtium Planting Calendar for South Dakota

Zone 4a ~145 day growing season · Full guide →

Last frost: May 6 · First frost: September 28 · 145 day season

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 20 May 20 – Jun 10
Bloom July 15 Jul 15 – Sep 30
Zone 4b ~155 day growing season · Full guide →

Last frost: May 1 · First frost: October 3 · 155 day season

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 8 May 8 – May 29
Bloom July 3 Jul 3 – Sep 25
Zone 5a ~166 day growing season · Full guide →

Last frost: April 25 · First frost: October 8 · 166 day season

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 2 May 2 – May 16
Direct Sow May 2 May 2 – May 23
Bloom June 27 Jun 27 – Oct 3

Growing Tips for South Dakota

Direct-sow large seeds 1/2 inch deep after last frost; soak seeds overnight to speed germination (7-10 days). Nasturtiums dislike root disturbance so direct sowing is strongly preferred. Avoid fertilizing — poor soil brings the best bloom. Trailing types can cover banks and climb trellises; dwarf types suit containers. In hot climates (zones 9+) plant in fall for winter/spring bloom as plants struggle in peak summer heat.

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Frequently Asked Questions

When should I plant Nasturtium in South Dakota?

Planting dates for Nasturtium in South Dakota depend on your USDA zone. South Dakota spans zones 4a, 4b, 5a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is South Dakota for planting?

South Dakota contains USDA hardiness zones 4a, 4b, 5a. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Last updated: June 2026.