Longwood Gardens Dupont: The 2024 Season’s Star Vegetable and How to Grow It

This Dupont tomato stands out because its cold-hardy genetics let it thrive in USDA Zones 3-9, making it perfect for early spring or late fall harvests when other varieties struggle. 🌱 The secret lies in its indeterminate growth habit, which means it keeps producing fruit all season if you prune regularly and provide strong support.

Unlike many heirlooms, Dupont also resists common diseases like early blight, thanks to its thick, waxy skin that protects against cracking—ideal for humid climates or uneven watering. For best results, I recommend testing soil pH before planting, as Dupont performs best in slightly acidic conditions (around 6.0-6.8).

What really sets Dupont apart in the kitchen is its slicing and saucing versatility.

The meaty texture holds up beautifully in bruschetta or fresh salads, while its deep, sweet flavor shines in homemade pasta sauces. 🍅 I’ve found that harvesting when the fruit is still slightly firm (not fully ripe) allows for better shipping and storage—just let them ripen indoors at room temperature for peak flavor.

The high yield means you’ll have enough to share, freeze, or can for winter meals.

Dupont tomato traits and growing conditions

The Dupont tomato's cold tolerance comes from its genetic heritage as a French heirloom developed for northern climates. Unlike most tomatoes that struggle below 50°F, Dupont's cell membranes contain higher levels of unsaturated fatty acids, which remain fluid in cooler temperatures—this prevents cold damage to roots and leaves.

The variety also produces lycopene-rich skin that acts as a natural sunscreen, protecting against UV stress while maintaining its signature deep red hue even in cloudy conditions. 🌿

This tomato's indeterminate growth habit sets it apart from determinate varieties like Roma or Celebrity. While determinate plants grow to a fixed size and produce fruit all at once, Dupont continues vine growth throughout the season, requiring 6-8 feet of vertical support (like sturdy cages or trellises).

The key is strategic pruning: remove suckers (side shoots) below the first flower cluster to direct energy upward, while leaving lower leaves intact to shade fruit and prevent sunscald. Proper spacing (18-24 inches apart) also improves air circulation, reducing humidity levels that trigger fungal diseases like early blight.

Soil pH plays a critical role in Dupont's performance, with ideal levels between 6.0-6.8. At this range, the plant can efficiently absorb phosphorus and iron—nutrients essential for root development and chlorophyll production.

Test your soil before planting: if pH runs higher than 7.0, amend with elemental sulfur; if below 5.5, use lime. The variety's thick, waxy skin also helps it tolerate 20-30% soil moisture fluctuations without cracking, making it ideal for areas with inconsistent rainfall patterns. 💧

Temperature management is equally important. Seedlings should never face temperatures below 45°F or above 85°F—both extremes stunt growth. Once established, Dupont thrives in 70-80°F day temperatures, producing fruit most efficiently when night temps stay above 55°F.

The variety's disease resistance stems from its genetic diversity: unlike hybrid tomatoes that rely on single-gene traits, Dupont's heirloom lineage contains multiple resistance genes, making it less susceptible to common pathogens while maintaining robust flavor development.

For maximum yield, focus on consistent moisture—Dupont needs about 1-1.5 inches of water weekly, delivered at soil level to prevent fungal spores from splashing onto leaves. Mulch with 3-4 inches of straw to retain moisture and suppress weeds, while also keeping fruit clean and reducing soil-borne disease risks.

The indeterminate nature means you'll harvest continuously from mid-summer until frost, with each vine capable of producing 20-30 pounds of fruit when properly cared for. 🍅

What most gardeners don't realize is how Dupont's growth habit affects flavor. The continuous fruiting means each tomato develops over 30-40 days, allowing more time for sugar accumulation compared to determinate varieties that rush fruit production.

This results in a 2-3% higher soluble solids content (measured as Brix), giving Dupont its signature sweet-tart balance that excels in both fresh eating and cooked preparations.

Step-by-step Dupont tomato cultivation guide

Start your Dupont tomatoes indoors 6-8 weeks before your last frost date using seed-starting mix in small pots. Keep them under grow lights for 14-16 hours daily at 70-75°F during the day and 60-65°F at night.

Harden off seedlings by placing them outdoors for 2-3 hours daily the week before transplanting, gradually increasing exposure to sunlight and wind. 🌱 This toughens the plants so they don’t go into shock when moved to the garden.

When transplanting outdoors, wait until soil temperatures reach at least 55°F and nighttime temps stay above 50°F. Space plants 18-24 inches apart in rows 3 feet apart to allow for proper air circulation.

Mix 3-4 inches of compost into the top 6 inches of soil before planting, and add a 1-inch layer of straw mulch around each plant to retain moisture and suppress weeds. This organic matter also provides slow-release nutrients that keep plants thriving throughout the season.

Water consistently to maintain 1-1.5 inches of moisture per week, focusing on the soil rather than the leaves to prevent fungal diseases.

Use drip irrigation or soaker hoses to deliver water directly to the roots, especially in the morning to allow foliage to dry quickly. 💧 If you’re hand-watering, aim for the base of the plant and avoid wetting the leaves.

For organic pest control, spray plants with a mix of 1 tablespoon neem oil per quart of water every 2 weeks to deter aphids and whiteflies, and plant companion crops like basil or marigolds nearby to repel pests naturally.

Watch for signs of blossom end rot (black bottoms on fruit) or cracking (radial splits), both of which can occur with inconsistent watering. To prevent these issues, maintain even soil moisture and consider adding 1 tablespoon of calcium-rich material (like crushed eggshells or gypsum) to the planting hole.

Harvest tomatoes when they’re deep red and slightly firm—they’ll ripen further at room temperature. Store unripe tomatoes in a paper bag with a banana to speed up ripening using natural ethylene gas. 🍅

For peak flavor, pick tomatoes in the morning when they’re cool and crisp. If you need to store them, keep whole, unwashed tomatoes in a single layer on a shelf at 55-60°F for up to 2 weeks. Avoid refrigerating until fully ripe, as cold temperatures destroy flavor compounds.

To preserve your harvest, slice tomatoes and freeze them in 1-cup portions with a little olive oil to prevent browning, or make homemade sauce by simmering chopped tomatoes with garlic and herbs for 30-40 minutes before canning.