When to plant morning glory in Pittsburgh, Pennsylvania
April 24 – May 8
Direct-sow outdoors · typical Pittsburgh yearClimate basis: NOAA station Emsworth L/d Ohio Rvr, PA (USC00362574), 6 mi (10 km) from downtown Pittsburgh (ZCTA 15222 centroid), elevation 717 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 (April 24). One year in ten still freezes after May 11.
The Pittsburgh year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to May 11
Every method, with its sources
Direct-sow outdoors
Apr 24 – May 8Iowa 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 (Apr 24). 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."