When to Plant in Pennsylvania

Pennsylvania's frost dates range from mid-April in the southeast around Philadelphia to late May in the mountainous central regions. Southeastern PA gets a noticeably longer growing season than the Poconos or State College.

Spring weather in Pennsylvania can be unpredictable. A warm spell in March doesn't mean frost season is over — experienced gardeners wait for consistent warm soil temperatures before planting tender crops.

Common Mistakes

Planting too early after a warm March — Pennsylvania springs are unpredictable with late cold snaps.
Not hardening off seedlings — the transition from indoor starts to outdoor beds needs to be gradual.
Overlooking the difference between eastern and western PA frost dates — they can differ by 2-3 weeks.
Skipping succession planting — stagger lettuce and bean plantings every 2 weeks for continuous harvest.

FAQ

What is the last frost date?

The last frost date is the typical date in spring when your area has its final frost. After this date, it's generally safe to plant warm-season crops outdoors.

When should I start tomatoes indoors in Pennsylvania?

Start tomato seeds indoors about 6–8 weeks before your last frost date. For most of PA, that means late February to mid-March.

Can I plant before the last frost?

Yes — cool-season crops like lettuce, peas, spinach, and broccoli can handle light frost and should be planted 4–6 weeks before your last frost date.

Why does timing vary so much within Pennsylvania?

The southeastern part of PA near Philadelphia is warmer and lower in elevation, while the central mountains and northern tier stay colder longer. Frost dates can differ by several weeks.

What if I live in a frost-free area?

Pennsylvania doesn't have frost-free areas, but the Philadelphia region has a longer growing season. Enter your zip code in the app for your exact dates.

How does Plan My Garden create my schedule?

You enter your zip code, and we look up your local frost dates. Then based on the crops you pick, we calculate when to start seeds, transplant, and harvest — personalized to your location.