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When to plant crocuses in Philadelphia: 12 October – end of December

In Philadelphia, crocus: plant from 12 October to the end of December.

Bulbs are best planted early in the window: late-planted bulbs may flower later or less well. Late planting works only while the soil can be dug. Mulch after planting.

The average daily temperature here stays above 0 °C all winter, and at least three months average 7 °C or less: our rule of thumb for the winter cold spring bulbs need. Sources: Iowa State University Extension, Wisconsin Horticulture Extension, UNH Extension, RHS.

Crocus in Philadelphia: soil, season and weather

Nights then average below 0 °C in December–February; the coldest, January, averages -2.5 °C.

Planting12 October – end of December
First autumn frost11 November
Coldest nightsJanuary, -2.5 °C
Soil back at 1 °C in springalready in the first week of January
Daylight11:20 on 12 October
Daylight at the winter solstice9:20

The same dates in Philadelphia hold for Garlic, Tulip, Daffodil and Hyacinth.

Crocus in Philadelphia: depth, winter cold, pests and pets

Plant Dutch crocuses (Crocus vernus) about 12 cm deep and 9 cm apart; smaller species go 7–10 cm deep (RHS).

In Philadelphia the average daily temperature stays at 10 °C or lower for about 21 weeks a year (our estimate from ten years of monthly weather). For this bulb Wisconsin Horticulture Extension gives a cold period of 15–17 weeks at about 2–10 °C. The winter here gives that in the ground, so the bulbs need no pre-chilling.

Crocuses multiply on their own (they naturalise); in a lawn, hold off mowing until their leaves die back (RHS).

Birds, squirrels and rodents damage crocuses; planting under metal mesh may reduce losses (RHS). Spring crocus gives dogs and cats vomiting and diarrhoea; do not confuse it with autumn crocus (Colchicum), which is very toxic (Pet Poison Helpline).

Sources: RHS, Wisconsin Horticulture Extension, Pet Poison Helpline.

Crocus in nearby cities

Around Philadelphia, Allentown is 8 days earlier and Dover 15 days later.

CityDistanceDateDifference
Trenton45 km13 October – end of December1 day later
Allentown77 km4 October – 30 December8 days earlier
Atlantic City92 km23 October – end of December11 days later
Dover93 km27 October – end of December15 days later
New York130 km21 October – end of December9 days later
Baltimore144 km23 October – end of December11 days later

Where to buy crocus for planting in Philadelphia

Planting stock goes into the ground from 12 October to the end of December; buy it before that. Within 15 km of Philadelphia OpenStreetMap lists 9 garden centres, 84 markets and 20 farm shops (collected 7 October 2026).

Places: © OpenStreetMap contributors, ODbL.

Questions

When to plant crocuses in Philadelphia?

In Philadelphia, crocus: plant from 12 October to the end of December. Bulbs are best planted early in the window: late-planted bulbs may flower later or less well. Late planting works only while the soil can be dug. Mulch after planting.

When is the last spring frost in Philadelphia?

Last spring frost around 3 April, first autumn frost around 11 November.

Other crops in Philadelphia, with their dates