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Pennsylvania spans four USDA hardiness zones — 5a in the northern highlands, 6a/6b across the central counties, and 7a along the southeastern corridor. Those zones don’t just change what you can grow — they shift your entire planting calendar by three to four weeks. A cilantro grower in Philadelphia can direct-sow outdoors a full month before someone in Erie should even be starting seeds indoors.
This guide gives you zone-specific planting dates for the most common culinary herbs — basil, cilantro, parsley, dill, thyme, oregano, sage, rosemary, chives, and mint — plus indoor start timing, fall planting windows, and the one cold-hardiness mistake that kills more herbs than any pest.
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Cool-Season Herbs
Warm-Season Herbs
Perennial Herbs
Zone-by-Zone Planting Calendar
Indoor Start Timing
Fall Planting
📅 Herb Growing Calendar — Pennsylvania (Zones 5a–7a)
Spring Plant
Peak Growth
Harvest
Fall Plant
Dormant
🌱 Herb Quick Reference — Pennsylvania
PA Frost Dates and What They Mean for Herb Timing
Every herb planting decision starts with your last frost date. Get this wrong by even two weeks and you’re either losing plants to frost or waiting too long to harvest before summer heat arrives.
Pennsylvania’s zones create dramatically different growing windows. Zone 7a gardeners in Philadelphia and Chester County have roughly 8 weeks more frost-free growing time than Zone 5a gardeners in Potter or Sullivan counties.
| PA Region | USDA Zone | Avg Last Spring Frost | Avg First Fall Frost | Frost-Free Days |
|---|---|---|---|---|
| Northern PA (Erie plateau, Pocono highlands) | 5a–5b | May 10–15 | Sep 15–25 | 120–135 |
| Central PA (State College, Altoona, Harrisburg area) | 5b–6b | Apr 20–May 5 | Oct 1–15 | 145–175 |
| Western PA (Pittsburgh metro, Allegheny County) | 6a–6b | Apr 15–25 | Oct 10–20 | 175–195 |
| Eastern PA (Philadelphia, Lehigh Valley, Delaware Valley) | 6b–7a | Mar 28–Apr 10 | Oct 20–Nov 5 | 195–225 |
How to use this table: Find your region, then add or subtract weeks from the planting dates throughout this guide. If you’re in Zone 6b Pittsburgh, your “last frost” is around April 20. A crop that says “2 weeks before last frost” goes in around April 6.
Cool-Season Herbs: Cilantro, Parsley, Dill, Chives
Cool-season herbs are your earliest movers. They prefer soil temperatures of 50–65°F and actually bolt (go to seed) faster in summer heat — so getting them in early isn’t just possible, it’s essential.
Cilantro is the most cold-tolerant common culinary herb. Direct-sow outdoors 2–4 weeks before your last frost date — it germinates best between 55–68°F. In Zone 7a (Philadelphia area), that means late February to mid-March. Zone 5a gardeners should wait until late April.
Parsley is slow to germinate — expect 2–3 weeks from seed to sprout — so start it 8–10 weeks indoors before last frost, or direct-sow 4–6 weeks before last frost. It tolerates light frost once established.
Dill dislikes root disturbance, so direct-sow is preferred. Plant 2–4 weeks before last frost. It germinates in 7–14 days in cool soil. Succession-plant every 2–3 weeks through June for a continuous harvest.
Chives are incredibly cold-hardy — perennial in all PA zones — but for first-year starts, direct-sow outdoors 4–6 weeks before last frost or start indoors 8–10 weeks early.
Warm-Season Herbs: Basil
Basil is the one herb that will punish you for impatience. It’s a true tropical and needs both air and soil temperatures above 60°F before transplanting. Cold soil stunts basil permanently — a plant that spent two weeks in 50°F soil never fully recovers.
Start basil indoors 4–6 weeks before your last frost date. Transplant outside only after overnight lows are consistently above 50°F — not just the daytime highs. In Zone 5a (northern PA), that’s often not until early June.
The hardening-off trap: Even after hardening off basil, a single night below 50°F can blacken leaves and stunt growth. Check your 10-day forecast before transplanting — Pennsylvania spring weather is notoriously unpredictable through mid-May.
Perennial Herbs: Thyme, Oregano, Sage, Rosemary, Mint
Perennial herbs are planted once and return each year — with some important zone caveats. Rosemary is the wildcard: it’s technically a perennial but isn’t reliably cold-hardy in Zones 5a or 6a without protection.
Thyme and oregano are cold-hardy to Zone 4 — plant any time from 2 weeks before last frost through early fall. They establish best in cool weather and don’t need coddling once rooted.
Sage is hardy to Zone 4 as well. Best planted in spring, 2–4 weeks before last frost, or in early September for fall establishment before winter.
Rosemary is hardy only to Zone 7 without protection. Zone 7a gardeners in southeastern PA can grow it as a true perennial with some mulching. Zone 6 and below: treat it as an annual or overwinter it indoors.
Mint spreads aggressively and establishes in any zone. Plant transplants after last frost, or direct-sow in spring. Use containers to control spread — mint planted directly in garden beds will take over.
Zone-by-Zone Herb Planting Calendar
Use the region buttons to highlight your row. Dates are approximate — always cross-check with your 10-day forecast in spring.
| PA Region | Last Frost (Avg) | Cilantro / Dill / Chives | Parsley | Basil | Perennials |
|---|---|---|---|---|---|
| Eastern PA (Phila., Zone 7a) | Apr 1–5 | Feb 25–Mar 10 | Feb 20–Mar 1 | May 1–10 | Mar 15–Apr 15 |
| Western PA (Pittsburgh, Zone 6b) | Apr 15–25 | Mar 25–Apr 5 | Feb 25–Mar 10 | May 10–20 | Apr 1–20 |
| Central PA (State College, Zone 6a) | Apr 25–May 5 | Apr 1–15 | Mar 1–15 | May 15–25 | Apr 10–May 1 |
| Northern PA (Erie/Pocono, Zone 5a–5b) | May 10–15 | Apr 15–May 1 | Mar 15–Apr 1 | Jun 1–10 | Apr 20–May 15 |
Staggered sowing for cilantro and dill: Both bolt quickly in summer heat. Sow a fresh batch every 2–3 weeks from your first outdoor date through early June for a continuous harvest window.
Indoor Start Timing
Not every herb benefits from indoor starts. Some actively dislike being transplanted. Here’s a rule of thumb: if it has a long taproot (cilantro, dill, fennel), direct-sow. If it’s a slow germinator (parsley, basil, thyme), starting indoors gives you a head start.
| Herb | Zone 7a (Eastern PA) | Zone 6a–6b (Central/Western PA) | Zone 5a–5b (Northern PA) | Start Method |
|---|---|---|---|---|
| Basil | Feb 15–Mar 1 | Mar 1–15 | Mar 25–Apr 10 | Indoors only |
| Parsley | Jan 15–Feb 1 | Feb 1–15 | Feb 15–Mar 5 | Indoors or direct |
| Thyme | Feb 1–15 | Feb 15–Mar 1 | Mar 1–15 | Indoors or transplant |
| Oregano | Feb 1–15 | Feb 15–Mar 1 | Mar 1–15 | Indoors or transplant |
| Sage | Feb 1–15 | Feb 15–Mar 1 | Mar 1–15 | Indoors or transplant |
| Cilantro (direct sow) | Feb 25–Mar 10 | Mar 25–Apr 5 | Apr 15–May 1 | Direct sow preferred |
| Dill (direct sow) | Mar 1–15 | Apr 1–15 | Apr 20–May 5 | Direct sow preferred |
| Chives | Feb 1–15 | Feb 15–Mar 1 | Mar 1–20 | Indoors or direct |
Fall Planting: A Second Window Most Gardeners Miss
Pennsylvania’s fall is one of the most underused herb-growing windows. Cool-season herbs planted in late summer produce all the way to hard frost — and sometimes beyond with light row cover.
The fall window works because temperatures are cooling toward cool-season herbs’ sweet spot (50–65°F), rather than away from it. Cilantro sown in late August often outperforms spring cilantro because it never bolts before you want it to.
| Herb | Eastern PA (Zone 7a) | Central/Western PA (Zone 6) | Northern PA (Zone 5) |
|---|---|---|---|
| Cilantro | Aug 15–Sep 15 | Aug 1–Sep 1 | Jul 20–Aug 15 |
| Dill | Aug 15–Sep 1 | Aug 1–Aug 20 | Jul 20–Aug 10 |
| Parsley | Aug 1–Sep 1 | Jul 20–Aug 20 | Jul 10–Aug 1 |
| Chives | Aug 15–Sep 15 | Aug 1–Sep 1 | Jul 20–Aug 15 |
Perennial fall planting: Thyme, oregano, and sage can also be planted in early September — they’ll establish roots before frost and return stronger the following spring. Aim for 6–8 weeks before your first fall frost.
Season planning: Check our month-by-month Pennsylvania planting guide to keep your garden producing all year. Browse all Pennsylvania vegetable guides for companion planting ideas.
Frequently Asked Questions About Planting Herbs in Pennsylvania
1. When is it safe to plant basil outside in Pennsylvania?
Basil needs both air and soil temperatures consistently above 60°F before transplanting outdoors. In Zone 7a (Philadelphia area), that’s typically May 1–10. In Zone 6a/6b (Pittsburgh, Central PA), expect May 10–20. In Zone 5a (northern PA), wait until June 1–10 to be safe. Cold soil stunts basil permanently — it’s never fully recovered from an early chill.
2. Can I plant herbs before the last frost in Pennsylvania?
Yes — but only the cold-tolerant ones. Cilantro, parsley, dill, chives, thyme, oregano, and sage can all go out 2–4 weeks before your last frost date. Basil is the exception: it will not tolerate frost or cold soil. Keep basil indoors until overnight lows are reliably above 50°F.
3. Will rosemary survive winter in Pennsylvania?
Rosemary is cold-hardy to about Zone 7. In southeastern PA (Zone 7a), it can survive winter outdoors with mulching and a protected spot. In Zone 6 and below — Pittsburgh, Central PA, northern PA — it will die back without protection. Most Zone 6 gardeners either treat rosemary as an annual or bring it indoors in a pot before the first frost.
4. Why does my cilantro bolt so fast in Pennsylvania summers?
Cilantro bolts (goes to seed) when temperatures consistently exceed 75°F, which happens across all PA zones by June or July. The fix is timing, not technique: plant your first batch as early as possible in spring, then succession-sow every 2–3 weeks through early June. A second round in late summer (August) often outlasts the spring crop.
5. Should I start herb seeds indoors or buy transplants?
For basil, parsley, thyme, oregano, and sage — starting indoors (or buying transplants) makes sense because they’re slow to establish from seed. For cilantro, dill, and fennel — direct-sow only. These herbs have taproots that don’t tolerate transplanting well; they’ll bolt quickly if their roots are disturbed.
6. What’s the difference between herb planting dates in Zone 5a vs Zone 7a Pennsylvania?
Zone 5a (northern PA highlands) has a last frost around May 10–15; Zone 7a (southeastern PA) averages a last frost of March 28–April 10. That’s a 5–6 week difference. For basil specifically, Zone 7a growers can transplant around May 1, while Zone 5a growers should wait until June 1 or later. For cool-season herbs like cilantro, Zone 7a can direct-sow outdoors in late February — a full 6–8 weeks before northern PA.
Continue Reading: Pennsylvania Herb Gardening
- How to Grow Herbs in Pennsylvania — soil, spacing, watering, and harvesting for PA gardens
- Best Herbs to Grow in Pennsylvania — top picks by zone with grow difficulty ratings
- Growing Herbs in Pennsylvania — complete hub with all herb guides
- Best Vegetables to Grow in Pennsylvania — full vegetable growing guide for PA gardeners
