When to plant morning glory in Sioux Falls, South Dakota
May 1 – May 15
Direct-sow outdoors · typical Sioux Falls yearClimate basis: NOAA station Sioux Falls, SD (USW00014944), 2 mi (3 km) from downtown Sioux Falls (ZCTA 57104 centroid), elevation 1430 ft, on the 1991–2020 climate normals. Direct-sow morning glory from approximately the dates above, anchored to the median last spring 32°F freeze (May 1). One year in ten still freezes after May 14.
The Sioux Falls year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to May 14
Every method, with its sources
Direct-sow outdoors
May 1 – May 15Iowa State University Extension lists morning glory by name among annuals to direct-seed "after the threat of frost is past in the spring", and Colorado State's seed-starting table asterisks morning glory as best suited to direct seeding, placing it two weeks before the frost-free date; the registry's reconciliation policy takes the later, more frost-conservative Iowa State interval for this frost-tender vine. Anchored to the median last spring freeze (May 1). Iowa State University Extension and Outreach · Colorado State University Extension
Start seeds indoors
Not calculatedNo indoor-start window is encoded because Colorado State's asterisk flags morning glory as best suited to direct seeding rather than an indoor start.
Transplant outdoors
Not calculatedThe cited extension guides do not time an outdoor transplanting window for this crop.
Fall planting
Not calculatedNo source-backed fall planting rule exists for this crop in the registry, so no fall window is calculated.
These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.
Crop rule sources (2)
- Iowa State University Extension and Outreach: Direct Seeding Vegetables and Annuals - Preparation and Care | Yard and Garden (accessed 2026-07-25)"Direct-seed most annual flowers after the threat of frost is past in the spring and when the soil warms ups."
- Colorado State University Extension: Growing Annual Plants from Seed (accessed 2026-07-25)"Table 1: Starting times for seeds grown indoors and in cold frames, shown as number of weeks to start seed before average frost-free date."