Shopping for tomato varieties can be overwhelming. Which variety is best for your Pacific Northwest garden and growing conditions?

In this article, I provide an easy way to narrow down the seemingly infinite options when it comes to tomato varieties:

• Go with open-pollinated varieties so that you can save your own seeds
• Select disease-resistant varieties for a better chance of success

As a regenerative gardener in the PNW, I find that open-pollinated, disease-resistant varieties help me achieve two main goals: a bountiful tomato harvest and sustainable land stewardship

This guide will help you select the best disease-resistant heirloom tomatoes for your PNW garden, so you’re one step closer to a pantry shelf full of homemade sauce for the winter.

Our climate can be particularly challenging for tomato cultivation due to wet, cool springs and early onset of blight, selecting the right tomato variety is crucial for success

→ Did you know that there are genes within different tomato species that helps them to be more disease-resilient? For example, the Ph-2 and Ph-3 genes help tomatoes resist late blight, and the I and I-2 genes help prevent Fusarium Wilt. These genetic markers can be continued through seed saving techniques by gardeners, so that heirloom varieties can fight off different pathogens in your home garden.

Why Choose Disease-Resistant Heirloom Tomatoes?

Obviously, you want more yields and a shelf full of homemade sauce. But why else should you choose disease-resistant tomatoes?

Have you considered that disease-resistant tomatoes also are important for regenerative gardening practices?

Regenerative gardening follows principles that prioritize sustainability, biodiversity, and soil health. When selecting tomato varieties for your garden, disease-resistant heirloom or landrace tomatoes align perfectly with these principles. Here's why:

Disease Resistance for Healthier Ecosystems

1. Reduced Need for Chemical Treatments: In the Pacific Northwest, high rainfall can lead to fertilizer and pesticide runoff issues.  This makes disease-resistant tomatoes even more important so we can minimize the need for chemical fungicides and pesticides. In turn, we can create a healthy garden ecosystem.
2. Enhanced Plant Health and Productivity: Healthier plants are more robust and productive, which provide a steady supply of tomatoes throughout the season. They contribute organic matter to the soil, improving its structure and fertility over time

Open-Pollinated Heirloom and Landrace Varieties for Resilience

1. Preserving Genetic Diversity: Heirloom and landrace tomatoes are open-pollinated, which maintains genetic diversity essential for adaptability and resilience to pests, diseases, and environmental changes.
2. Seed Saving and Sovereignty: Open-pollinated varieties allow you to save seeds, promoting local adaptation to our region and reducing dependence on commercial seed companies.
3. Cultural and Historical Significance:
   • Heirloom and landrace varieties often carry rich histories and cultural significance. Select these tomatoes to help preserve and uplift agricultural heritage. Heirlooms help you to pass down valuable knowledge and traditions to future generations.
   • These varieties often have unique flavors, colors, and textures that add diversity and interest to your meals for a richer the culinary experience.

Soil Health and Regenerative Practices

1. Promoting Soil Fertility: Disease-resistant and open-pollinated tomatoes thrive with regenerative practices like composting, cover cropping, and crop rotation, which enhance soil health and support beneficial microbial communities.
2. Encouraging Sustainable Water Use: Robust, disease-resistant plants require less water, aligning with regenerative principles of water conservation. While most of the year is rainy here, July and August - essential plant development time for tomatoes - can be nearly rain-free. Mulching helps retain soil moisture and reduces irrigation needs.

Key Diseases to Watch For

Tomato plants are susceptible to several diseases that can severely impact their health and productivity. Understanding these common diseases and the importance of choosing disease-resistant varieties is crucial to maintain a thriving garden.

In the PNW, we must be especially vigilant against diseases like early blight and late blight, which thrive in our region’s wet spring and fall conditions.

Blight

Types: Early Blight and Late Blight

• Early Blight (Alternaria solani): This fungal disease causes dark, rings on older leaves, which can lead to defoliation, reduced fruit yield, and sunscald on the fruit.
• Late Blight (Phytophthora infestans): A severe disease that kills off your tomato plants before they’ve produced their full harvest. Dark, water-soaked lesions on leaves, stems, and fruit lead to plant collapse. Late blight is particularly devastating in wet conditions.

Why Resistance is Crucial: The Pacific Northwest’s cool, damp climate creates a perfect environment for blight. Select tomato varieties that have proven resistance to this pervasive disease to ensure a healthy garden

Fusarium Wilt

• Fusarium oxysporum: This soil-borne fungal disease causes yellowing and wilting of leaves. Eventually, it clogs the plant’s vascular system so it can’t access water and nutrient transport.

Why Resistance is Crucial: Fusarium wilt persists in soil for many years, even beyond standard crop rotation plans. Resistant varieties are the most effective way to manage this disease.

Mosaic Virus

• Tomato Mosaic Virus (ToMV): This virus causes mottled, mosaic-like patterns on leaves, stunted growth, and reduced fruit quality. It spreads through infected tools, hands, and plants.

Why Resistance is Crucial: Once present, mosaic viruses can be difficult to eradicate and control. Resistant varieties help prevent the spread of the virus.

Septoria Leaf Spot

• Septoria lycopersici: This fungal disease creates small, circular spots with dark borders and gray centers on leaves. Severe infections lead to significant leaf drop, which leads to sunscald on fruit

Why Resistance is Crucial: Septoria leaf spot can rapidly defoliate plants, so photosynthesis decreases. This in turn leads to less fruit yield. Resistant varieties minimize the impact of this disease.

With disease-resistant tomato varieties, you can significantly reduce the risk of these common diseases in your PNW garden. The end result? Healthier plants, higher yields, and a more sustainable gardening practice. Everyone wins!

Interactive Chart of Disease-Resistant Heirloom Tomatoes

To help you make the best choice for your garden, we've created an interactive chart of popular disease-resistant heirloom tomato varieties. Below, we’ll outline which ones are best suited to the different climates of the Pacific Northwest. This chart allows you to filter and compare varieties based on resistance to specific diseases, growth habits, fruit characteristics, and more.

The chart highlights varieties with strong resistance to common regional diseases such as early and late blight.

Things to Keep in Mind About Disease-Resistant Heirloom Tomatoes:

Resistance is Different from Total Immunity

Dr. Margaret Tuttle McGrath, an Associate Professor ofPlant Pathology and Plant-Microbe Biology at Cornell University, shares a key distinction about disease resistant tomatoes. She says, “No resistant plant variety is immune, thus some symptoms will develop even on the most resistant variety under high disease pressure.”

There are Different Strains of Diseases

As UMass Amherst notes, there are different strains of common tomato diseases such as early blight.

This means that while a tomato variety may be “late blight resistant,” it might not be able to fight against the strain of blight that you have in your area.

Since these strains spread locally, you can slightly increase your garden’s protection if you buy seeds from a local source who selects seed for disease resilience.

Open-pollinated vs. Hybrid

Hybrid tomatoes are grown for their higher level of disease resistance - they have modern-day technology as an advantage. Unfortunately, hybrids come with the downside of seed dependency and regulations.

Open-pollinated varieties, like heirlooms, let you save your own seeds. These seeds can adapt to local conditions and gardening methods over time.

A way to get the best of both worlds is to purchase seeds from one of Joseph Lofthouse’s landrace or breeding collections, which will often have hybrids and heirlooms mixed in together.

Landraces are populations of cultivated plants that have become adapted to local environmental conditions through natural and farmer-led selection over many generations.

It’s important to note that not all landraces will have hybrids mixed in. This is a technique that some seed breeders like Lofthouse utilize, however. In this way, some of the hybrid-level resistance comes in to the gene pool while you still get to save your seeds from the healthiest plants each year.

While improving disease resistance through selective breeding in your home garden might not give you the same level of immunity as modern hybrids, it’s a good way to support your own seed sovereignty and self-sufficiency.

Maintain Best Practices

Don’t set yourself up for failure and grow your tomatoes with poor conditions. You want to give your tomatoes their best shot at giving you an abundant harvest. You’ll still want to avoid practices that can lead to diseased plants, such as:

• overhead watering
• inadequate pruning
• poor airflow
• crowded plants
• leaf contact with soil

How to Choose the Right Variety for Your Garden

The right tomato variety for you depends on several factors, from your local climate to the space available in your garden.

Coastal PNW (Western Washington and Oregon, Coastal British Columbia)

Climate Considerations:

• Marine Influence: Mild temperatures with frequent fog and high humidity. Select tomatoes that are resistant to the diseases that accompany humidity, such as early blight.
• Summer Dryness: While springs are wet, summers can be dry, requiring diligent watering practices. Implement drip irrigation to conserve water and prevent foliar diseases.
• Wind Exposure: Coastal winds can affect plant growth and microclimates.

Best Tomato Picks:

• Wisconsin 55 Slicing Tomato: Bred for short and humid seasons, this variety will help your tomatoes to resist disease and cracks.
• Cuor di blu Albegna: Well-adapted to maritime PNW weather, don’t need as much heat to mature
• Florida Everglades: Does well in cool, humid, and moist conditions
• Marmande: Grows well outdoors during cooler summers
• Mountaineer: Great for humid conditions

Inland Valleys (Willamette Valley, Puget Sound Basin)

Climate Considerations:

• Warmer Summers: Greater heat accumulation during the summer compared to coastal areas. This makes tomatoes especially vulnerable to sun scald.
• Seasonal Dry Spells: Prolonged dry periods in summer necessitate regular irrigation. Mulching and drip irrigation are a huge help with this, as are drought-resistant varieties.
• Frost Risk: Early and late frosts can be a concern in shoulder seasons. Look for fast-maturing tomato varieties.

Adaptation Tips:

• Heat-Tolerant Varieties: Select tomatoes that thrive in warmer conditions, such as 'Sungold' or 'Early Girl.'
• Frost Protection: Be prepared with frost cloths or cold frames to protect young plants in early spring and late fall.

Best Tomato Picks:

Eva Purple Ball: Doesn’t mind the heat, early to mature

Tropic VFN: Performs well in hot conditions

Mountainous Regions (Cascades, Olympic Mountains)

Climate Considerations:

• Short Growing Season: Cooler temperatures and shorter growing periods. Look for fast-maturing tomato varieties that are also disease resistant.
• High Rainfall: Significant precipitation, especially at higher elevations.
• Variable Microclimates: Large variations in temperature and moisture within short distances.

Adaptation Tips:

• Raised Beds for Warmth: Use raised beds to improve soil drainage and warmth.
• Season Extension: Utilize greenhouses, hoop houses, or row covers to extend the growing season.

Best Tomato Picks:

• Baylor Paste: Performs well outside, mold resistance
• Crimson Sprinter: Quick to mature, does well in cool temperatures
• Florida Everglades: Does well in cool and moist conditions
• Manitoba: Fast growing, disease resistance for cool climates

High Desert Plateaus (Eastern Washington, Eastern Oregon)

Climate Considerations:

• Hot Summers and Cold Winters: Extreme temperature fluctuations between seasons.
• Low Humidity: Dry conditions with minimal rainfall.
• High Sun Exposure: Intense sunlight and UV radiation.

Adaptation Tips:

• Drought-Resistant Varieties: Choose tomatoes like 'Cherokee Purple' or 'Roma' that can withstand dry conditions.
• Shade Cloths: Use shade cloths during the peak heat of summer to protect plants from sunburn.
• Efficient Irrigation: Implement drip irrigation systems to maximize water use efficiency and minimize evaporation.

Best Tomato Picks:

• Arkansas Traveler: Great for sandy soils and hot conditions
• Mountain Spirit: Well-adapted to high altitude growing and dry soils

Additional PNW-Specific Factors to Consider:

• Soil Types: Coastal areas may have sandy or loamy soils, while inland valleys often have rich, fertile loam. Everywhere else deals with tough clay. Adjust soil amendments and fertilization accordingly.
• Pests and Wildlife: Coastal areas may experience more slug and snail pressure, whereas inland regions might deal with deer and other wildlife.
• Cultural Preferences: Certain heirloom varieties have been locally adapted, such as 'Oregon Spring' developed by Oregon State University.

PNW Picks for All-Around Varieties:

• Homestead 24: Very adaptable to different growing conditions and climates
• Legend: Out of the breeding program at Oregon State University, this fast-maturing blight resistant variety is renown in our area for its performance
• Martino’s Roma: Compact growing habit is great for containers and urban gardens
• Oregon Spring: A classic early variety out of OSU’s breeding program

The right tomato variety can make a significant difference in your gardening success. Disease-resistant heirloom tomatoes not only help you cultivate a healthier garden but also play a crucial role in the preservation of these treasured varieties for the future. Use our interactive chart to find the perfect match for your garden and enjoy a bountiful harvest!

Additional Tomato-Growing Resources:

• Visual Guide to PNW Leaf Diseases
• Growing Tomatoes in a Greenhouse: Mistakes to Avoid
• How to Propagate Tomatoes from Cuttings
• Regenerative Tomato Grow Guide
• Huge Tomato Harvests: Organic Tips