When to plant basil in Pennsylvania
Pennsylvania’s average last spring frost is May 1, and the first fall frost typically arrives around October 10 — about 162 frost-free days (USDA zones 5a, 5b, 6a, 6b, 7a, 7b). Basil needs 30–60 days to mature, which fits comfortably within Pennsylvania's growing season.
Pennsylvania covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant basil in Pennsylvania: the short answer
For a spring planting, plant out May 8 – May 25, with seeds started indoors Mar 20 – Apr 3. Wait until the soil is at least 65°F and frost is over.
Succession sow again in Pennsylvania: Jun 5 · Jun 26 · Jul 17 · Aug 7
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow basil in Pennsylvania, step by step
- Start seeds indoors (Mar 20 – Apr 3). Sow seeds ⅛ inch deep in seed-starting mix under bright light. They take 5-10 days to sprout, fastest in soil around 80°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. It needs at least six to eight hours of direct sun a day and loose soil at least 10 inches deep, with a pH between 6.0 and 7.0. Dig in compost before planting.
- Plant out (May 8 – May 25). Space plants about 10 inches apart in rows 12 inches apart. It is killed by frost, so nothing goes outside until the danger has passed.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: aphids, Japanese beetle, slugs. Diseases and disorders: basil downy mildew, fusarium wilt, damping off.
- Harvest (from about Jun 14 – Jul 14). Basil takes 30-60 days to reach harvest. Cold soil stalls it - wait for warm nights. Pinch above a leaf pair every couple of weeks and remove flower buds to keep leaves coming. Downy mildew-resistant varieties are worth seeking out.
Figures come from our crop data; dates use Pennsylvania’s average frost dates. More in the full basil growing guide.
Basil planting dates by USDA zone in Pennsylvania
Pennsylvania spans USDA zones 5a, 5b, 6a, 6b, 7a, 7b. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the basil dates shift with them.
When to plant basil in nearby states
| State | Last frost | Plant out |
|---|---|---|
| Pennsylvania (this page) | May 1 | May 8 – May 25 |
| New Jersey | April 20 | Apr 27 – May 14 |
| Delaware | April 14 | Apr 21 – May 8 |
| Maryland | April 14 | Apr 21 – May 8 |
| District of Columbia | April 10 | Apr 17 – May 4 |
| Virginia | April 15 | Apr 22 – May 9 |
| West Virginia | May 5 | May 12 – May 29 |
Questions gardeners in Pennsylvania ask
When is the best time to plant basil in Pennsylvania?
Plant basil transplants outdoors in Pennsylvania between May 8 and May 25. That timing is set by Pennsylvania's average last spring frost of May 1; Pennsylvania spans several climates, so cooler and higher parts of the state run later.
When should I start basil seeds indoors in Pennsylvania?
Start seeds indoors between March 20 and April 3, about 5 weeks before the last frost, so the seedlings are ready to plant out from May 8.
What is the latest I can plant basil in Pennsylvania?
About September 10. Basil needs at least 30 days to mature, and frost around October 10 ends the season, so later plantings risk being cut short.
When will basil planted in Pennsylvania be ready to harvest?
Planted on time, basil is usually ready from about June 14 to July 14, 30-60 days after planting.
When is the last frost in Pennsylvania?
On average around May 1, with the first fall frost around October 10 - about 162 frost-free days. Your town may differ by two weeks or more.