Pennsylvania planting calendar

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

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

Brussels Sprouts planting timetable for Pennsylvania

Stage	When in Pennsylvania	Anchor
Start seeds indoors	late January (January 31)	12 weeks before the last frost (late April)
Transplant outside	mid-April (April 11)	14 days before the last frost (late April)
First harvest (estimate)	early July (July 10)	~90 days from transplant

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 brussels sprouts dates

Pennsylvania's last spring frost averages late April and first fall frost mid-October, which sets the whole planting clock. Pennsylvania runs from cold northern mountains to a mild southeastern corner. Philadelphia gardens almost two zones warmer than the northern tier. Sow early — brussels sprouts bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Brussels sprouts are a long-season crop — transplant outdoors 2–3 weeks before the last spring frost once seedlings are 10–15 cm tall, or start a fall crop by counting back 90–100 days from the first fall frost and setting transplants then. Flavour sweetens after the first hard frost (below -2 °C), making them one of the few vegetables that actually improves with autumn cold. Zones 9–10 can grow them as a winter crop but the lack of hard frost reduces flavour development.

Frost-risk note

Don't plant before late April — a hard freeze can still set young plants back. In the northern Allegheny plateau (zone 5a) the safe date runs a week or two later.

Regional variation within Pennsylvania

the northern Allegheny plateau (zone 5a) runs roughly 1-2 weeks behind the state average; the southeast around Philadelphia (zone 7b) can plant 1-2 weeks earlier.

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 early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: 7-29 °C (45-85 °F).
Spacing: 18-24 inches (45-60 cm) between plants.
Days to harvest: ~90 days from planting out.

Frequently asked questions

When is the best time to plant brussels sprouts in Pennsylvania?

In Pennsylvania (mostly USDA zone 6b), sow brussels sprouts indoors around late January, transplant outdoors mid-April (before the last frost, late April), and harvest from early July. Brussels Sprouts are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

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 brussels sprouts in Pennsylvania?

Yes. Pennsylvania's dominant zone 6b supports brussels sprouts — the key is timing. Brussels Sprouts are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

Does the planting date change across Pennsylvania?

the northern Allegheny plateau (zone 5a) runs roughly 1-2 weeks behind the state average; the southeast around Philadelphia (zone 7b) can plant 1-2 weeks earlier.

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

The same early window suits peas, lettuce, spinach, and onion sets.

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.