When to Plant Broccoli in Pennsylvania
Published: April 21, 2026
Pennsylvania gardeners in Zone 6a have a 31-week growing season for broccoli (March 30 to November 1). Pennsylvania's spring and fall windows both work well for broccoli — some gardeners plant both successions for a long harvest. This guide gives exact dates for Pennsylvania based on your local frost calendar.
Broccoli Planting Dates for Pennsylvania
| Start seeds indoors | February 16–23 |
| Last frost (average) | March 30 |
| Transplant outdoors | March 2–12 |
| Direct sow outdoors | March 2–12 |
| Expect first harvest | May 1 – May 21 |
| Fall crop start | August 23–September 2 |
| Fall harvest | October 22 |
| First fall frost (average) | November 1 |
Dates above assume Zone 6a, the most common zone in Pennsylvania. Gardeners in cooler Scranton (Zone 5b) plant 1–2 weeks later; warmer Philadelphia (Zone 6a) can plant 1–2 weeks earlier.
Growing Broccoli in Pennsylvania's Climate
Pennsylvania's moderate Zone 6a climate is well-suited to broccoli with minimal special accommodation. The standard transplant calendar works as written, and harvest windows line up with what seed packets recommend without adjustment.
Succession planting extends your broccoli harvest significantly in Pennsylvania. A second planting 3 to 4 weeks after the first gives you a backup in case of pest pressure and extends the total harvest window into early fall.
Common broccoli pests to watch for in Pennsylvania include Cabbage Worm and Cabbage Looper. The first line of defense is companion planting: Onion and Garlic planted nearby discourage several of these pests by confusing host-plant identification or repelling adults before they can lay eggs. Weekly garden walks in the early morning catch problems when they're still manageable.
Broccoli Garden Calendar for Pennsylvania
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | Start seeds indoors | Use grow lights; warm soil to 70–75°F for best germination |
| March | Transplant outdoors | Soil temp must be 40°F+; nighttime lows above 50°F |
| April | — | Dormant season |
| May ← | Watch for bolting | Harvest promptly; spring heat arrives quickly |
| June | — | Dormant season |
| July | — | Dormant season |
| August | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| September | — | Dormant season |
| October | — | Dormant season |
| November | First frost approaches | Harvest remaining broccoli; cover plants on frost nights |
| December | — | Dormant season |
Broccoli Growing Tips for Pennsylvania Gardeners
- •For spring: start indoors 6 weeks before last frost and transplant outdoors 4 weeks before last frost.
- •For fall: start indoors in summer — count 10 weeks back from your first fall frost date.
- •Pennsylvania's moderate climate supports succession planting — sow new transplants or seeds every 3 weeks during spring to extend the harvest window into fall.
- •Harvest heads before any yellow flowers open — once flowers show, flavor declines quickly.
Companion Planting for Broccoli in Pennsylvania
In Pennsylvania's moderate climate, planting broccoli with Onion and Garlic helps deter pests and improve soil. Avoid planting near Tomato and Pepper, which inhibit broccoli growth through root chemistry or shared pest pressure. See the full broccoli companion planting guide for the complete list.
Broccoli Planting Dates by City in Pennsylvania
Top cities in Pennsylvania — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant broccoli in Pennsylvania?
In Pennsylvania (Zone 6a), start broccoli seeds indoors around February 16–23 and transplant outdoors around March 2–12 — 4 weeks before the state's average last frost of March 30.
What is the last frost date in Pennsylvania?
Pennsylvania's average last frost date is March 30 in the state's most common Zone 6a. Frost dates vary by city — higher elevations and northern counties run 1 to 3 weeks later than the state average. See the city list below for city-level frost dates.
Can I grow broccoli year-round in Pennsylvania?
broccoli is a cool-season crop in Pennsylvania, with spring and fall windows. Summer heat bolts the plants before they can produce a harvestable crop. Succession planting every 2–3 weeks stretches the harvest window.
What broccoli varieties grow best in Pennsylvania?
For Pennsylvania's Zone 6a, Waltham 29, Calabrese, and Green Magic perform well across conditions.
When do I start broccoli seeds indoors in Pennsylvania?
Start broccoli seeds indoors in Pennsylvania around February 16–23, which is 6 weeks before the state's average last frost of March 30. Use grow lights and keep soil temperatures at 70–75°F for fastest germination.