When To Plant Tomatoes In Oregon? (Best Time and Expert Tips)

When To Plant Tomatoes In Oregon? (Best Time and Expert Tips)

Oregon’s moderate climate makes it an excellent place to grow juicy, flavorful tomatoes. But proper timing is key to getting a successful harvest. This article provides tips on when to plant tomatoes in Oregon, varieties that thrive there, and how to help your plants flourish.

Choosing the Best Time to Plant Tomatoes in Oregon

Tomatoes need warm soil and air to grow well. In Oregon, gardeners typically plant tomatoes in late spring after the last frost date has passed. Here are some guidelines on timing by region:

  • Western Oregon – Plant from mid-May to early June, after soil reaches 60°F.
  • Willamette Valley – Plant late May to mid-June, once the danger of frost has passed.
  • Central Oregon – Plant in early June when nighttime temps stay reliably above 45°F.
  • Eastern Oregon – Plant early to mid-June once the soil has warmed to 60°F.

Pay close attention to weather forecasts, as a late cold snap can damage tender tomato transplants. Use season-extending devices like walls of water, row covers, or cloches if planting earlier.

Smart Tips for Planting Tomatoes in Oregon

Here are some tips to get your tomato plants off to a strong start:

  • Choose a sunny, well-draining spot. Tomatoes need at least 6-8 hours of direct sun daily.
  • Prepare the soil by mixing in several inches of compost or aged manure. Tomatoes thrive in loose, fertile, slightly acidic soil.
  • Start seeds indoors 6-8 weeks before last spring frost. Use individual pots or cell packs and keep seedlings warm (70°F).
  • Gradually acclimate plants to outdoor conditions over 7-10 days (hardening off).
  • Transplant seedlings 18-36 inches apart, burying stems up to the lowest leaves.
  • Install stakes, cages, or trellises at planting for support.
  • Mulch around plants to retain moisture and reduce weeds. Straw and leaves work great.
  • Water plants 1-2 inches per week. Provide extra water during hot, dry stretches.

Tomato Varieties Suited for Oregon Gardens

With thousands of tomato varieties to choose from, here are some recommended top performers for Oregon:

Early Season Tomatoes

  • Siletz – Early maturing in just 55 days. Medium-sized fruits with outstanding flavor.
  • Legend – An extremely early tomato that thrives in cool climates. Produces meaty 4-6 oz. Slicer fruits.
  • Oregon Spring – Ultra early, resistant to late blight. Bears are sweet, cherry-sized fruits.

Mid-Season Tomatoes

  • Early Girl – Very popular, bears juicy 4-6 oz. Slicer fruits with great disease resistance.
  • Celebrity – All-purpose tomato with great flavor. Medium-large fruits are very disease-resistant.
  • Sweet 100 – Prolific cherry tomato produces very sweet, early-maturing fruits.

Late Season Tomatoes

  • Brandywine – Cherished heirloom variety, with large 1-2 lb. pink beefsteak fruits and incredible flavor.
  • San Marzano – Italian paste tomato prized for making sauces and canning.
  • Black Krim – Striking deep reddish-black color with a rich, sweet flavor.

Caring for Tomato Plants in Oregon

Giving tomato plants proper care throughout the season ensures healthy, bountiful harvests:

  • Use sturdy cages, stakes, or trellises for support. Prune any suckers and excess foliage.
  • Apply 2-3 inches of mulch around plants to retain moisture and prevent weeds. Replenish as needed.
  • Water plants 1-2 inches per week with drip irrigation or soaker hoses. Provide extra water during hot, dry periods.
  • Feed plants monthly with a balanced organic fertilizer. The fish emulsion also works excellently.
  • Scout for common pests like hornwormsaphidswhiteflies. Remove by hand or apply organic sprays.
  • Prevent diseases through drip irrigation, proper spacing, and crop rotation. Remove any diseased foliage promptly.
  • Gently tap blossoms daily when temps exceed 70°F at night to improve pollination and fruit set.
  • Harvest tomatoes when fully colored but still firm. Store at room temperature out of the direct sun.

Dealing with Tomato Growing Challenges in Oregon

Oregon’s climate presents some unique challenges for tomato growers:

Cool Nights

  • Protect plants with cloches or fabric row covers when temps fall below 45°F.
  • Heavily mulch around plants with straw or black plastic to retain warmth.
  • Select early-season varieties bred to set fruit in cooler conditions.
  • Use dark containers around plants to absorb and radiate heat.

Excessive Rain and Humidity

  • Stake and trellis plants to improve airflow and reduce foliar diseases.
  • Prune leaves and suckers regularly for better circulation.
  • Use drip irrigation instead of sprinklers to keep foliage dry.
  • Apply organic anti-fungal sprays weekly, like diluted baking soda.

Late Blight Prevention

  • Choose late blight-resistant varieties like Legend, Oregon Spring, or Defiant.
  • Avoid overhead watering; use drip irrigation instead. Water early so plants can dry out.
  • Stake and prune plants to encourage good airflow.
  • Remove and destroy any infected plants ASAP. Sterilize tools after use.
  • Apply organic copper fungicide sprays preventively every 7-10 days.

Getting a Head Start with Indoor Seed Starting

Starting tomato seeds indoors gives plants an early boost and maximizes Oregon’s relatively short growing season:

When to Start Seeds

  • Count backward from transplant date – tomatoes need 6-8 weeks of growth before hardening off.
  • Start seeds in mid to late March for transplanting in late May or early June.
  • Refer to a seed starting calendar for guidance based on various maturity dates.

Choosing Seeds

  • Pick compact varieties suitable for containers – determinate, dwarf, patio, potatoes, etc.
  • Quick maturing varieties – Early Girl, Oregon Spring, cherry tomatoes.
  • Source seeds from reputable suppliers – seed catalogs and local garden centers.
  • Both heirloom and hybrid seeds will work well. Hybrids offer more disease resistance.

Growing Medium

  • Use a sterile seed starting mix, or make your own with peat, vermiculite, or compost.
  • Ensure excellent drainage and airflow by not packing down too firmly.
  • Bake mix at 180°F for 30 minutes to kill any soil-borne diseases.


  • Choose cell packs, flats, peat pots, or other small containers with drainage holes.
  • Recycle yogurt cups, egg cartons, etc. Be sure to sterilize them first.

Seeding and Care

  • Moisten soil mix and allow to drain before planting seeds.
  • Plant seeds 1⁄4 inch deep per packet instructions. Gently cover with mix or vermiculite.
  • Use a spray bottle to water the seeds to prevent washing away gently.
  • The ideal temperature is 70-80°F for germination. Use heat mats as needed.
  • Place seeds in sunny areas or under grow lights on a 14-16 hour daily cycle.
  • Thin seedlings to the strongest one per cell after the first true leaves appear.

Hardening Off and Transplanting

  • Gradually acclimate seedlings to outdoor conditions over 7-10 days.
  • Start by placing plants outdoors in the shade for a few hours, slowly increasing the time.
  • Bring seedlings back indoors each night until it’s time to transplant into the garden.
  • Transplant on a cloudy day or in the evening to avoid transplant shock.

Growing Tomatoes Successfully in Containers

Don’t have space for a garden? You can easily grow tomatoes on a balcony, patio, or doorstep with these container-growing tips:

Choosing Tomato Varieties

  • Look for compact, determinate varieties suited for pots.
  • Go for bush types like Tumbler, Mountain Spring, and Patio.
  • Cherry tomatoes produce well with limited root space.
  • Quick maturing varieties – long season types will suffer.

Pot Size

  • Use at least a 5-gallon container; bigger is better.
  • Larger pots allow for larger plants and higher yields.
  • Make sure the container has drainage holes to prevent waterlogging.

Soil Mix

  • Use a quality potting mix, not dense garden soil.
  • Mix in compost or worm castings to enrich with nutrients.
  • Maintain a slightly acidic pH between 6.0 and 6.5.

Watering and Fertilizing

  • Check soil moisture daily; don’t let plants dry out.
  • Apply water-soluble fertilizer every 2-3 weeks.
  • Place trays under pots to catch excess water drainage.

Sun and Support

  • Position container plants in a spot with at least 6 hours of direct sun.
  • Use stakes, cages, or trellises to support plants and improve yields.
  • Prune leaves and stems regularly to encourage good airflow.

Dealing with Common Tomato Pests and Diseases

Proactive gardeners can prevent or minimize pest and disease issues through smart practices:

Frequent Tomato Pests

  • Aphids – Knock off with water spray or apply insecticidal soap.
  • Tomato Hornworms – Hand-pick large green worms to prevent major defoliation.
  • Whiteflies – Use yellow sticky traps to monitor. Spray neem oil or insecticidal soap.
  • Cutworms – Prevent with seedling collars. Pick worms off plants at night.
  • Flea Beetles – Small holes in leaves. Apply organic insecticides at first signs of damage.
  • Slugs/Snails – Hand-pick at night. Trap in shallow beer containers. Use iron phosphate bait.

Common Tomato Diseases

  • Early Blight – Brown spots on older leaves. Improve airflow. Use resistant varieties.
  • Late Blight – Spreads rapidly in wet conditions. See late blight prevention tips.
  • Blossom End Rot – Dark spots on the bottoms of fruit. Result of irregular watering. Mulch and use drip irrigation.
  • Fusarium/Verticillium Wilt – Leaves wilt and die. Rotate crops and improve soil texture.
  • Powdery Mildew – White fungal growth on leaves. Space plants for good airflow.
  • Tomato Mosaic Virus – Yellow mottled leaves, stunted growth. Control aphids that spread it. Remove and destroy infected plants quickly.

Tips for Getting the Biggest, Most Abundant Tomato Harvest

Here are some best practices for maximizing your tomato yields:

Choose the most productive varieties

  • Look for indeterminate types that bear fruit all season long.
  • Select disease-resistant varieties adapted to your growing region.
  • Prioritize varieties known for higher yields.

Start plants strong

  • Sow seeds at proper depth and spacing in seed trays.
  • Use fresh, sterile seed starting mix.
  • Moderate fertilizing – avoid overfeeding seedlings.
  • Give adequate warmth, sunlight, and gentle handling.

Site selection

  • Ensure full sun exposure – minimum 6 hours of direct sun.
  • Prepare organic, nutrient-rich soil with excellent drainage.
  • Allow for good airflow circulation.
  • Easy access to water for irrigation.

Support plants properly

  • Install sturdy stakes, cages, or trellises.
  • Prune plants for optimal structure and airflow.
  • Heavily mulch around plants to conserve moisture.

Consistent care

  • Maintain even, adequate watering – 1-2 inches weekly.
  • Feed plants monthly with a balanced organic fertilizer.
  • Monitor closely for pests and diseases.
  • Test soil pH and maintain it in the ideal range.

Optimize conditions

  • Use season-extending methods like cloches and row covers.
  • Time plantings for your local growing season.
  • Trap heat around plants using containers.
  • Radiate warmth into the soil using dark landscape fabric.

Promote pollination

  • Attract pollinators like bees to your garden.
  • Gently tap blossoms daily to release pollen.
  • Consider hand-pollinating flowers for the best fruit set.

Stagger plantings

  • Grow early, mid and late-season varieties.
  • Succession plant every 2-3 weeks.
  • Fill gaps from any frost damage.

Diligent harvesting

  • Pick ripe tomatoes every day or two.
  • Never leave overripe fruit on vines to rot.
  • Pull up spent plants before heavy fall frost.

Enjoying the Fruits of Your Labor – Preserving the Harvest

Make the most of your carefully tended tomato crop! Here are some tips for enjoying or preserving your harvest:

Storing Fresh Tomatoes

  • Keep ripe tomatoes at room temperature out of direct sun. Never refrigerate!
  • Place singly on the counter, not touching, to avoid speeding ripening.
  • Allow tomatoes to ripen on the vine for the absolute best flavor.

Canning Tomatoes

  • Select firm, defect-free tomatoes. Don’t overripe or damaged fruit.
  • Closely follow trusted canning recipes and proper processing methods.
  • Add bottled lemon juice to acidify and achieve a safe pH for water bath canning.
  • Process pint or quart jars for 85 minutes in a hot water bath.

Freezing Tomatoes

  • Scald and peel tomatoes. Core and slice or dice into pieces.
  • Arrange in a single layer on a cookie sheet. Freeze, then promptly transfer to bags.
  • Alternatively, spread pieces on a tray and freeze before bagging – great for sauces!

Drying Tomatoes

  • Slice tomatoes about 1/2 inch thick and remove seeds. No need to peel.
  • Use a food dehydrator at 135°F for 6-8 hours until leathery.
  • For sun drying, place slices on racks and bring indoors at night. Takes several days.
  • Store dried tomatoes in oil or freeze them for longer-term storage. Use within 1 year.

Root Cellar Storage

  • Pick unripe green tomatoes before heavy fall frost and wrap them in newspaper.
  • Check frequently and remove any rotten tomatoes. The ideal storage temperature is 55°F with high humidity.
  • Tomatoes stored below 50°F may fail to ripen properly. Use within 2 months for best quality.


Oregon gardeners can grow incredible tomatoes bursting with flavor with proper timing and care. Pay attention to planting dates, choose suitable varieties, support plants well, and control pests. Time seed starting and succession planting to maximize the shorter growing season. Whether enjoyed fresh off the vine or preserved, homegrown Oregon tomatoes are a real taste of summer!

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