How to Grow Potomac Tomato
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Potomac Tomato
Solanum lycopersicum 'Potomac'
vegetablePotomac is a determinate, medium-sized tomato variety bred for disease resistance and reliable production in humid climates. It produces medium-sized red fruits (4-6 oz) with good flavor and is particularly known for its resistance to early and late blight, making it an excellent choice for gardeners in high-humidity regions.
When should you plant Potomac Tomato in your zone?
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Example Potomac Tomato timeline · Pittsburgh, PA (Zone 6b)
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Plant Potomac Tomato
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Potomac Tomato
Around Jun 24≈ 68 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Potomac Tomato dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9; particularly suited to zones 5-8 where humidity and fungal diseases are concerns
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Get my Potomac Tomato timeline →Growth Stages
Seedling
4-6 weeksSmall plants with first true leaves emerging; delicate growth requiring consistent moisture and bright light
Start seeds indoors 6-8 weeks before last frost; provide 12-16 hours of grow light; maintain 70-75°F soil temperature
Transplant/Establishment
2-3 weeksYoung plants with 4-6 true leaves, ready for hardening off and transplanting into garden after last frost
Harden off gradually by exposing to outdoor conditions over 7-10 days; plant out after all frost danger passes
Vegetative
3-4 weeksRapid growth of stems and foliage; first flower clusters beginning to form; determinate growth habit becoming evident
Install sturdy cages or stakes early; maintain consistent watering; apply mulch around base; prune lower suckers if desired for air circulation
Flowering & Fruit Set
3-4 weeksAbundant yellow flowers appearing in clusters; small fruit developing after pollination; plant reaching mature height (3-4 feet)
Ensure adequate pollination (bees or gentle shaking); maintain steady watering; provide consistent fertilizer; watch for early blight on lower leaves
Fruiting & Harvest
4-8 weeksMature fruits ripening from green to red; determinate growth pattern concentrating fruit set; most fruit ripening within 2-3 week window
Harvest ripe fruits regularly to encourage continued production; remove heavily diseased foliage (disease resistance still requires good air flow); continue consistent watering
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Hand-pick; use Bacillus thuringiensis (Bt); encourage parasitic wasps
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Yellow sticky traps; neem oil spray; strong water spray; reflective mulch
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Spray with water; neem oil; insecticidal soap; increase humidity
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Remove lower foliage; improve air circulation; mulch to prevent soil splash; fungicide if severe (copper, chlorothalonil)
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Resistant variety (Potomac provides resistance); remove infected tissue; fungicide; avoid overhead watering
Uses
Fresh salads and cooking
CulinaryMedium-sized, flavorful fruits excellent for slicing in salads, sandwiches, and fresh salsas. Good all-purpose tomato for cooking down into sauces and soups. [source]
Canning and preserving
CulinaryDeterminate ripening allows bulk harvest perfect for canning whole or as sauce. Meaty interior and good acidity ideal for safe water-bath canning. [source]
Antioxidant-rich nutrition
MedicinalRich in lycopene and vitamin C, components associated with reduced cardiovascular disease risk and cancer prevention. [source]
Disease management in gardens
HouseholdPotomac's resistance to early and late blight reduces the need for fungicide applications, supporting organic and sustainable gardening practices. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Pick fruits at 'breaker stage' (first blush of red) to ripen indoors for better disease management and to encourage continued flowering; fully ripe fruits can be picked directly; determinate types fruit heavily all at once, so process or preserve surplus; harvest before first frost
Fun Facts
- 🌱 Potomac was developed by the USDA specifically to address the fungal blight problems common in humid eastern U.S. climates, particularly the Potomac Valley region.
- 🌱 As a determinate variety, Potomac produces its entire crop within a concentrated window (2-3 weeks), making it ideal for gardeners who want to preserve or can large quantities at once.
- 🌱 Tomatoes planted deep will develop roots along the buried stem, creating a stronger root system—a trick especially useful if seedlings become leggy indoors.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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