When to plant celosia in Pittsburgh, Pennsylvania

April 24 – May 8

Transplant outdoors · typical Pittsburgh year

Climate 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. Transplant celosia outdoors 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.

Last spring freezeApril 241-in-10 after May 11
First fall freezeOctober 271-in-10 before Oct 13
Frost-free season≈ 186 daysmedian at 32°F
Hard freeze, 28°Apr 12 – Nov 5kills even hardy greens
USDA zone7a0 to 5°F winter low — not frost timing

The Pittsburgh year

Start seeds indoorsMar 27 – Apr 10
Transplant outdoorsApr 24 – May 8
Direct-sow outdoorsApr 24 – May 8
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 11
Celosia in Pittsburgh · freeze context from Emsworth L/d Ohio Rvr, PA, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Mar 27 – Apr 10

University of Maryland's celosia production guide states seed is sown 4 weeks before the last frost date, which is the only frost-anchored figure found (Minnesota's 10-weeks guidance is anchored to the outdoor planting date, not to frost, so it cannot be used), giving a two-week sowing span opening 4 weeks before the median last freeze. Anchored to the median last spring freeze (Apr 24). University of Maryland Extension · University of Minnesota Extension · University of Illinois Extension

Transplant outdoors

Apr 24 – May 8

University of Maryland says to sow or transplant celosia in the field after the danger of frost has passed, so the window opens at the median last freeze; note Maryland's stricter companion rule of night temperatures consistently above 65 to 70 degrees F is not frost-anchored and cannot be expressed here, so the window's opening day is optimistic in cool-summer areas. Anchored to the median last spring freeze (Apr 24). University of Maryland Extension · University of Minnesota Extension · University of Illinois Extension

Direct-sow outdoors

Apr 24 – May 8

The same University of Maryland sentence covers direct sowing — sow or transplant celosia in the field after the danger of frost has passed — so direct sowing opens at the median last freeze, with Illinois independently classing celosia a tender annual. Anchored to the median last spring freeze (Apr 24). University of Maryland Extension · University of Minnesota Extension · University of Illinois Extension

Variety assumption: Assumes Celosia argentea in its crested (cockscomb) and plumed forms; Maryland warns that exposure below 60 degrees F stunts plants and triggers premature flowering, so the frost-anchored window opens earlier than the temperature at which celosia actually thrives.

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.

This week, not a typical year:
Crop rule sources (3)

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