Pennsylvania planting calendar

When to plant garlic in Pennsylvania — sow, transplant & harvest dates

Pennsylvania is mostly USDA zone 6b (range 5a-7b). Dates below are derived from garlic's frost tolerance and Pennsylvania's frost window — not generic national averages.

Garlic planting timetable for Pennsylvania

Stage	When in Pennsylvania	Anchor
Plant cloves outdoors	late August — mid-September (September 10)	~35 days before Pennsylvania's first fall frost (mid-October)
First harvest	early May the following year	~240 days from autumn planting

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Pennsylvania's climate shifts the garlic dates

Pennsylvania's first fall frost averages mid-October, which sets the autumn planting clock — cloves need 4-6 weeks of root growth before the ground freezes. Pennsylvania runs from cold northern mountains to a mild southeastern corner. Philadelphia gardens almost two zones warmer than the northern tier.

Garlic is the unusual one — plant cloves in autumn (4-6 weeks before the first hard fall frost) so they put down roots before winter, then break dormancy in spring and bulb up over the long days of early summer. Cold-winter zones grow hardneck varieties; mild-winter zones do better with softneck.

Frost-risk note

Get cloves in before the ground freezes solid; in the northern Allegheny plateau (zone 5a) mulch heavily with 10-15 cm of straw to stop freeze-thaw heaving.

Regional variation within Pennsylvania

the northern Allegheny plateau (zone 5a) should plant at the earlier end of the window and grow hardneck types; the southeast around Philadelphia (zone 7b) can plant later and lean on softneck varieties.

Philadelphia — USDA zone 7b
Pittsburgh — USDA zone 6b
Harrisburg — USDA zone 7a
Allentown — USDA zone 6b
Erie — USDA zone 6b

What else to plant in Pennsylvania around then

The same autumn slot suits overwintering onions, shallots, and a final sowing of spinach or mache.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: Soil 10-15 °C (50-60 °F) at planting.
Spacing: 4-6 inches (10-15 cm) between plants.
Days to harvest: ~240 days from autumn planting.

Frequently asked questions

When is the best time to plant garlic in Pennsylvania?

In Pennsylvania (mostly USDA zone 6b), plant garlic cloves outdoors around late August — mid-September — roughly 35 days before the first fall frost (mid-October). Cloves root through autumn, overwinter, then bulb up by early May next year. Garlic is fall-planted — cloves need winter chilling, so they go in the ground in autumn, root before the freeze, and bulb up the following summer.

What USDA zone is Pennsylvania?

Most of Pennsylvania sits in USDA hardiness zone 6b, with the state spanning roughly 5a-7b from the northern Allegheny plateau (zone 5a) to the southeast around Philadelphia (zone 7b). The last spring frost averages late April and the first fall frost mid-October.

Can you grow garlic in Pennsylvania?

Yes. Pennsylvania's dominant zone 6b supports garlic — the key is timing. Garlic is fall-planted — cloves need winter chilling, so they go in the ground in autumn, root before the freeze, and bulb up the following summer.

Does the planting date change across Pennsylvania?

What else can I plant in Pennsylvania around the same time?

The same autumn slot suits overwintering onions, shallots, and a final sowing of spinach or mache.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.