Pennsylvania · zones 5b–7b
When to plant tomatoes in Pennsylvania.
Sow or transplant between May 2 to Jul 2 in a typical year, keyed to Pennsylvania's median last frost around Apr 25. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Tomatoes dates for a typical Pennsylvania season.
1 · Start indoors
Mar 21 to May 21
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
May 2 to Jul 2
Keyed to the ~Apr 25 last frost. Sow 0.25" deep, 24" apart.
Harvest
~73 days later
~12 lb per plant over ~8 weeks.
Pennsylvania spans more than one climate: Zone 6 is the most common zone, but the state runs 5b to 7b. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
Pennsylvania growing notes
The valley fog that ripens Pennsylvania tomatoes also feeds their blight.
A pink beefsteak seed catalogs keep tracing back to this state
Brandywine, the big pink beefsteak most seed catalogs describe as an heirloom out of Pennsylvania Dutch country, is still grown across the state for exactly that reason, and it rewards the long, warm stretch a Pennsylvania summer can deliver in the southeastern counties. It is a full-season slicer, and gardeners on the colder Allegheny plateau do better starting it earlier indoors rather than expecting it to catch up once set outside, since a short season leaves a Brandywine plant with unripe fruit still on the vine at frost.
Fruit set itself has a heat ceiling worth knowing regardless of variety: pollen becomes unreliable once days consistently top 85 degrees with nights staying above 70, a combination Pennsylvania hits during the hottest stretches of summer even this far north. Blossoms that drop during that kind of heat wave are not a disease or a watering problem; they are the plant protecting itself, and fruit set resumes once temperatures ease back down.
Ridge-and-valley fog is a blight incubator
Cool, damp air settles into Pennsylvania's low ground overnight the way it does in any hill country, and a tomato bed sitting down in one of those valley bottoms wakes up to a heavier dew and a longer stretch of wet leaves than a bed on higher ground close by, exactly the setup early and late blight need to take hold. The lowest, oldest leaves show it first: dark spots ringed like a target work their way up the plant from there, a pattern that separates blight from the ordinary yellowing that comes with the end of any tomato season.
Keep every plant off the ground on a stake or cage so air can move freely through the leaves and the canopy dries out fast once the sun clears the morning fog. Once fruit starts sizing up, strip away the lowest foot or so of foliage, since those bottom leaves sit closest to the soil where blight spores splash up during a hard rain and contribute little to feeding the plant at that point anyway.
Hornworm hides in plain sight
Tomato hornworm is a genuinely large caterpillar, several inches long and colored to match the foliage almost exactly, which is why most gardeners find the damage, stripped stems and dark droppings on the leaves below, before they ever spot the insect itself. Run a hand along the stem where leaves have vanished and check the underside of nearby foliage; the caterpillar is usually sitting in plain sight once you know to look at the right height.
A white cottony cluster stuck to a hornworm's back is not a second pest, it is a parasitic wasp's eggs, and that caterpillar should be left exactly where it is. The wasp larvae are already killing the hornworm from the inside and will emerge to attack the next generation, which is a better long-term outcome for the bed than removing that one caterpillar by hand.
In Pennsylvania: watch for
The pests that find tomatoes here.
A middle-length season, about 172 frost-free days, means tomato, slicing overlaps tomato hornworm for a stretch each summer. Check plants every week or two and treat early.
Big green caterpillars strip leaves and leave black droppings.
Organic fix: Handpick at dusk; spray Bt on the young ones.
Clusters on new growth, sticky leaves, curling tips.
Organic fix: Blast with water, then insecticidal soap or neem.
Dark spots with concentric rings, starting on the lowest, oldest leaves.
Organic fix: Remove affected leaves, mulch to stop soil splash, space for airflow.
Greasy, water-soaked blotches in cool, wet spells. No rings, and not bottom-up.
Organic fix: Pull infected plants fast, keep leaves dry, use neem as a preventive.
Septoria leaf spot
Many small tan spots with dark brown edges, low leaves first, no rings inside.
Organic fix: Strip the lowest leaves, mulch against soil splash, stake for airflow.
Your season math: Pennsylvania gives tomatoes about 172 frost-free days, and it needs roughly 73 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting tomatoes in Pennsylvania: questions
When should I plant tomatoes in Pennsylvania?+
In a typical Pennsylvania year, sow tomatoes or set out transplants between May 2 to Jul 2, keyed to the state's median last frost around Apr 25. Your exact dates shift with your ZIP code and microclimate.
When do I start tomatoes seeds indoors in Pennsylvania?+
Start seeds inside about 6 weeks before set-out: roughly Mar 21 to May 21 for a typical Pennsylvania season.
What USDA zone is Pennsylvania?+
Pennsylvania spans zones 5b–7b, mostly zone 6. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many tomatoes plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.