Oregon · zones 6a–9a
When to plant tomatoes in Oregon.
Sow or transplant between Apr 22 to Jun 22 in a typical year, keyed to Oregon's median last frost around Apr 15. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Tomatoes dates for a typical Oregon season.
1 · Start indoors
Mar 11 to May 11
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Apr 22 to Jun 22
Keyed to the ~Apr 15 last frost. Sow 0.25" deep, 24" apart.
Harvest
~73 days later
~12 lb per plant over ~8 weeks.
Oregon spans more than one climate: Zone 8 is the most common zone, but the state runs 6a to 9a. 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.
Oregon growing notes
Seventy-three days from transplant to a ripe slicer is one of the toughest bets west of the Cascades, and one of the safest east of them.
Zone 8 on paper, two different growing seasons in practice
This state's hardiness zones run from a cold 6a and 6b to a mild 8a, 8b, and 9a, a wider spread than most single states carry, and a slicing tomato needing 73 days from transplant to first ripe fruit feels that gap more than most crops do. On the mild end, marine air off the coast and through the valley keeps summer nights cool, pleasant for people and slow for a fruit that wants to bank heat. On the cold end, east of the mountains, nights swing wider and winters bite harder, but summer days run hotter and steadier, which a slicer prefers once established.
Either way, this is a one-shot planting. With no fall window for slicing tomatoes here, the spring transplant is the only round this crop gets. Started indoors, this crop's seed wants no more than a quarter inch of cover, and once transplants go into the garden, space them 24 inches apart in the row so the sprawling foliage can dry between waterings. Oregon Spring, a slicer developed in-state to set fruit without much banked heat, is worth seeking out if last year's crop ripened late or not at all; it will not outproduce a full-season beefsteak type, but it finishes.
Three diseases that all start as spots, and how to tell them apart
Early blight and septoria leaf spot both take hold low on the older leaves first, and both look like trouble at first glance, but they are not the same fight. Early blight makes a spot with dark rings, like a target, and the yellow tissue around each ring spreads as the spot ages. Septoria leaf spot is smaller and more numerous, dozens of pinprick to pencil-eraser sized circles with a dark border and a pale gray middle, and if you look closely at that gray middle you will often find tiny black dots, the fungus fruiting inside its own lesion. Both climb the plant from the bottom up, so stripping infected lower leaves as soon as you spot either one buys time.
Late blight is the one to move fast on. It does not confine itself to neat spots; it makes irregular, water-soaked, almost greasy-looking blotches that can cover a leaf in a couple of days during a stretch of cool, wet weather, and a fine white fuzz often shows on the underside of those blotches in the early morning before the day warms up. It moves onto stems and green fruit, not just foliage, and a plant that looked fine on Monday can be collapsing by the weekend. The 24-inch row spacing this crop gets earns its keep here: more air movement means leaves dry faster after dew or rain, and all three of these diseases need wet leaf surfaces to get started.
Hornworms, aphids, and the twelve pounds a plant that makes the wait worth it
Tomato hornworms are easy to miss because they match the stem color exactly and feed mostly at dusk and dawn, but they leave evidence: dark droppings the size of a pencil eraser scattered on leaves and soil below wherever they are feeding, and a branch stripped of foliage that was full the day before. If you want to find the worm itself rather than just the evidence, a UV flashlight after dark makes them glow pale green against the plant, worth trying once before writing a plant off. Aphids cluster on new growth and leaf undersides; a strong water spray dislodges most of them without spraying anything stronger.
A healthy plant carried through all of it can produce around 12 pounds of fruit over the season. On a 73-day crop with only one planting window, the difference between a good year and a wasted spring usually comes down to how early the first spot or the first stripped leaf gets caught, not to anything done at planting time.
In Oregon: watch for
The pests that find tomatoes here.
A middle-length season, about 193 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: Oregon gives tomatoes about 193 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 Oregon: questions
When should I plant tomatoes in Oregon?+
In a typical Oregon year, sow tomatoes or set out transplants between Apr 22 to Jun 22, keyed to the state's median last frost around Apr 15. Your exact dates shift with your ZIP code and microclimate.
When do I start tomatoes seeds indoors in Oregon?+
Start seeds inside about 6 weeks before set-out: roughly Mar 11 to May 11 for a typical Oregon season.
What USDA zone is Oregon?+
Oregon spans zones 6a–9a, mostly zone 8. 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.