The Black Prince tomato plant is a prized heirloom variety known for its deep, rich color, complex flavor, and resilience in cooler climates.
Originating in Siberia, this tomato variety has captured the hearts of gardeners and chefs alike with its smoky-sweet taste and stunning dark-red to mahogany hue.
Whether you’re an experienced grower or a first-time gardener, cultivating Black Prince tomatoes is a rewarding journey that combines old-world charm with delicious results.
In this comprehensive guide, I’ll share with you everything you need to know—from starting seeds indoors to knowing exactly when to pluck those perfectly ripe fruits from the vine.
Let’s dig into what makes the Black Prince tomato plant so special and how you can enjoy a bountiful harvest.
Related: How to Grow and Care for the Chocolate Cherry Tomato Plant
Understanding the Black Prince Tomato Plant
The Black Prince tomato plant is a medium-sized indeterminate variety, meaning it continues to grow and produce fruit throughout the growing season until frost.
It typically reaches 4 to 6 feet tall and produces round to slightly oval fruits weighing between 5 to 7 ounces.
The skin of the fruit is thin and beautifully colored, ranging from dusky red to deep brown or purplish-black, especially when ripened in full sun.
What sets this tomato apart is not just its looks but also its rich, balanced flavor—earthy, slightly sweet, and less acidic than many other varieties. It’s ideal for fresh eating, slicing, salads, and even sauces where a deeper flavor profile is desired.
Key Features:
- Growth Habit: Indeterminate
- Maturity Time: 70–75 days from transplant
- Fruit Size: Medium (5–7 oz)
- Color: Deep red to mahogany
- Flavor: Rich, sweet, slightly smoky
- Climate Suitability: Performs well in cooler climates
This variety is perfect for home gardeners seeking both beauty and taste.
Starting Black Prince Tomato Seeds Indoors
Getting your Black Prince tomato plant off to a strong start begins with proper indoor seed starting.
Because this variety has a long growing season (typically 70–75 days from transplant), starting seeds indoors 6–8 weeks before your last expected frost date is essential—especially if you’re gardening in cooler regions.
Supplies You’ll Need:
- Black Prince tomato seeds
- Seed starting trays or small pots
- Seed starting mix (light and well-draining)
- Humidity dome or plastic wrap
- Spray bottle or watering can
- Grow lights or a sunny windowsill
Step-by-Step Instructions:
1. Prepare Your Containers and Soil
Fill your seed trays or pots with a sterile seed-starting mix. Avoid using regular garden soil, as it’s often too dense and may harbor diseases.
2. Sow the Seeds
Plant your Black Prince tomato seeds about ¼ inch deep. You can place 2–3 seeds per cell or pot, then thin them later to the strongest seedling.
3. Moisten the Soil
Use a spray bottle to mist the soil gently. It should be damp but not soggy. Cover the trays with a humidity dome or plastic wrap to retain moisture.
4. Provide Warmth and Light
Tomato seeds germinate best at temperatures between 70–80°F (21–27°C). Place your trays on a heat mat if needed.
Once seedlings emerge (usually within 5–10 days), remove the cover and provide 12–16 hours of bright light daily using grow lights or a sunny window.
5. Thin the Seedlings
When seedlings develop their first set of true leaves, thin them to one per cell or pot. Choose the healthiest, most vigorous one
6. Transplant to Larger Pots (Optional)
If your plants outgrow their seed trays before it’s time to plant outdoors, transplant them into 4-inch pots to continue growing strong roots
Pro Tip:
To encourage stocky, strong plants, run a small fan near your seedlings or gently brush the tops with your hand daily to mimic outdoor breezes. This strengthens the stems and reduces the risk of legginess.
Transplanting Black Prince Tomato Seedlings Outdoors
Once your Black Prince tomato plant seedlings are about 6–8 inches tall, have a few sets of true leaves, and nighttime temperatures consistently stay above 50°F (10°C), they’re ready to be transplanted into the garden. This is usually 2–3 weeks after your last expected frost date.
Step 1: Harden Off the Seedlings
Before transplanting, it’s crucial to harden off your seedlings to prevent transplant shock. This involves gradually introducing them to outdoor conditions over 7–10 days:
- Day 1–3: Place seedlings outside in a shaded, wind-protected area for 1–2 hours.
- Day 4–6: Increase exposure to sunlight and time outdoors to 3–4 hours.
- Day 7–10: Let them spend most of the day outside, including some direct sunlight. Bring them in at night until conditions are consistently warm.
Step 2: Choose the Right Location
The Black Prince tomato plant thrives in full sun (at least 6–8 hours per day) and in well-drained, fertile soil rich in organic matter.
Ideal soil conditions:
- pH between 6.2 and 6.8
- Loamy and well-aerated
- Amended with compost or aged manure
Step 3: Prepare the Planting Site
Space your plants 18–24 inches apart in rows about 30–36 inches apart. If using raised beds or containers, ensure they are deep enough—at least 12–18 inches—to support deep root growth.
Step 4: Plant Deep for Strong Roots
Remove the lower leaves and bury the seedling deeper than it was in the pot—up to the first set of leaves. Tomatoes develop roots along buried stems, which results in a sturdier, more drought-tolerant plant.
Step 5: Water and Mulch
- Water thoroughly after transplanting.
- Apply a 2–3-inch layer of mulch (straw, compost, or shredded leaves) around the base to retain moisture and suppress weeds.
Step 6: Add Support Early (Optional)
Install tomato cages, stakes, or trellises at the time of transplanting to avoid disturbing the roots later.
The Black Prince tomato plant, being indeterminate, benefits from early support to keep vines upright and fruit clean.
Compare: Ultimate Guide on Planting Tomatoes in Raised Beds
Caring for Black Prince Tomato Plants During the Growing Season
Once your Black Prince tomato plant is in the ground, consistent care is key to encouraging strong growth, high fruit production, and disease resistance.
These indeterminate plants will reward you with continuous harvests all season long if you meet their basic needs.
1. Watering
Tomatoes prefer deep, consistent watering. The goal is to maintain even soil moisture—never soggy, never bone dry.
- Water 1–2 inches per week, depending on rainfall and heat.
- Water at the base of the plant to avoid wetting the leaves (which can lead to disease).
- In hot weather, consider morning watering to keep plants hydrated throughout the day.
Tip: A soaker hose or drip irrigation system works best for tomato plants to minimize splashing and reduce disease pressure.
2. Fertilizing
Start fertilizing about 2–3 weeks after transplanting, once the plant has established.
- Use a balanced fertilizer (like 10-10-10) or one slightly higher in phosphorus (the middle number) to encourage blooming.
- Avoid overdoing nitrogen, which can cause lush foliage but few fruits.
- Once flowering begins, switch to a tomato-specific fertilizer rich in potassium for improved fruiting.
3. Pruning and Staking
Because Black Prince tomato plants are indeterminate, they will grow tall and sprawling without pruning.
- Remove suckers (the shoots that grow between the main stem and leaf branches) to direct energy into fruit production.
- Prune lower leaves that touch the ground to reduce the risk of soil-borne diseases.
- Use sturdy stakes, cages, or trellises to support the growing vines and improve air circulation.
4. Pest and Disease Management
Watch for common tomato pests and diseases like:
- Aphids, whiteflies, tomato hornworms
- Early blight, late blight, and leaf spot
Combat pests with:
- Insecticidal soap or neem oil
- Companion planting with basil, marigold, or nasturtiums to deter pests
Prevent disease by:
- Rotating crops yearly
- Mulching to reduce soil splash
- Watering at the base
- Removing infected leaves promptly
How to Tell When Black Prince Tomatoes Are Ripe
Recognizing when your Black Prince tomato plant is ready for harvest can be incredibly satisfying—and essential for enjoying the fruit at its peak flavor.
Unlike traditional red tomatoes, the Black Prince doesn’t turn a bright red hue, so judging ripeness takes a bit more observation and touch.
As the fruits mature, you’ll notice a rich transformation in color. They start off a dull green and gradually deepen into a dark, dusky red or mahogany with hints of brown or even purplish-black, especially when grown in full sun.
This unique coloration is one of the hallmarks of the variety, but it can make it trickier to determine exact ripeness by color alone.
One of the most reliable indicators is the feel of the fruit. A ripe Black Prince tomato will give slightly under gentle pressure—firm, but not hard, with a slight softness that signals juicy flesh inside.
If it still feels rigid or overly dense, it likely needs a few more days to develop its full flavor.
Additionally, a ripe fruit will often have a slight separation from the stem. You might notice the stem loosening or the fruit gently pulling away with ease when lifted or twisted. If you need to tug hard, it’s probably not ready yet.
A subtle, earthy aroma is another giveaway. When the fruit is ripe, it releases a sweet, tomato-rich fragrance—especially near the stem end.
Lean in close and trust your nose; the scent is nature’s way of telling you it’s harvest time.
Because the Black Prince tomato has a thinner skin than many commercial varieties, it’s best to harvest them just as they reach ripeness.
Leaving them too long on the vine can lead to splitting or bruising, especially after rain or overwatering.
If you’re expecting a heavy rain, go ahead and harvest those that are nearly ripe and let them finish ripening indoors on a windowsill.
Harvesting and Storing Black Prince Tomatoes
Harvesting tomatoes is more than just picking fruit—it’s about capturing the perfect moment when flavor, texture, and color come together in harmony.
With the Black Prince tomato plant, timing and technique make all the difference.
When harvesting, gently cup the tomato in your hand and lift or twist it slightly.
A ripe Black Prince should detach from the vine with minimal effort. If it resists, give it another day or two.
Because the skin of these tomatoes is relatively thin and delicate, it’s best to handle them with care to avoid bruising or tearing the surface.
Use clean garden snips such as this lightweight Modern Sprout Gardening Pruners (pictured ⬆) if needed, especially when harvesting in bulk.
Black Prince tomatoes tend to ripen at different times, especially since they are indeterminate growers and continue to produce throughout the season.
For the best flavor, try to harvest them just as they reach full color and feel slightly soft to the touch. This is when their flavor is richest—sweet, smoky, and a bit tangy, with a meaty interior perfect for slicing.
Once harvested, keep your tomatoes out of the refrigerator. Cold temperatures dull their flavor and alter the texture, making them mealy instead of juicy.
Instead, store them at room temperature, ideally in a single layer, away from direct sunlight. A kitchen counter or shaded shelf works well.
If you’ve picked a few fruits a bit early to avoid splitting from rain or pests, allow them to ripen indoors.
Place them stem-side down on a plate or tray, and check them daily. They’ll continue to mature and develop flavor over several days.
For longer-term storage, consider preserving excess fruit by making sauces, salsas, or sun-dried tomatoes.
Black Prince tomatoes, with their rich flavor and low water content, are excellent for slow-roasting and canning.
Common Problems and How to Fix Them
Even the most attentive gardeners face challenges when growing tomatoes.
The Black Prince tomato plant, while robust and resilient, is not immune to pests, diseases, and environmental stress.
Understanding the warning signs and acting quickly can make the difference between a struggling plant and a bountiful harvest.
😥 Cracking and Splitting
One of the most frequent issues with Black Prince tomatoes is fruit splitting, which often happens after heavy rainfall or inconsistent watering.
The plant absorbs water too quickly, causing the thin-skinned fruit to swell and crack.
To prevent this, water your plants consistently and evenly—especially during dry spells. Mulch around the base of your plants to maintain steady soil moisture levels.
If rain is expected, consider harvesting nearly ripe fruits early and letting them finish ripening indoors.
😥 Blossom End Rot
Blossom end rot appears as dark, sunken spots on the bottom of the fruit. It’s caused by a calcium imbalance, often triggered by irregular watering.
Ensure your watering routine is consistent and avoid letting the soil completely dry out between sessions.
While adding calcium (like crushed eggshells or bone meal) can help, the real key is maintaining soil moisture so the plant can absorb nutrients effectively.
😥 Early Blight and Leaf Spot
These fungal diseases are common in humid climates and appear as yellowing leaves with dark spots. They typically begin at the bottom of the plant and work their way up.
To manage blight:
- Prune lower leaves to increase air circulation.
- Avoid overhead watering.
- Remove and discard infected foliage promptly.
- Rotate crops each year and keep mulch around the base to reduce soil splash.
Copper-based fungicides or organic solutions like neem oil can also help if applied early.
😥 Pest Problems
Tomato hornworms, aphids, and whiteflies are notorious tomato pests. Hornworms can strip a plant of foliage quickly, while aphids and whiteflies weaken plants by sucking out their juices.
Inspect plants regularly, especially under the leaves. Handpick hornworms or use organic sprays like neem oil or insecticidal soap to deter smaller insects.
Companion planting with basil, marigolds, or nasturtiums can naturally help repel pests.
Also read: 10 Best Companion Plants for Lettuce
😥 Wilting and Yellowing
If your Black Prince tomato plant wilts even when the soil is moist, it could be a sign of fusarium or verticillium wilt, which are soil-borne fungal diseases.
Unfortunately, there’s no cure once the plant is infected.
To avoid this:
- Buy disease-resistant seed varieties when available.
- Rotate crops each season.
- Remove and dispose of infected plants to prevent spread.
By staying vigilant and acting early, most of these problems can be managed or even avoided altogether.
A healthy plant is a productive one, and the rewards—rich, flavorful Black Prince tomatoes—are well worth the effort.
Frequently Asked Questions about the Black Prince Tomato Plant
Q: How tall do Black Prince tomato plants get?
A: Black Prince tomato plants typically grow to a height of 4 to 6 feet, although in ideal growing conditions with proper staking and pruning, they can reach up to 7 feet tall. As indeterminate growers, they don’t stop growing after setting fruit, which means they’ll continue to stretch and produce new growth throughout the season. For best results, support them with tall stakes, trellises, or cages to keep the vine upright and prevent the fruit from touching the ground.
Q: Is Black Prince tomato determinate or indeterminate?
A: The Black Prince tomato plant is indeterminate, which means it produces fruit continuously throughout the growing season rather than all at once. This growth habit makes it ideal for gardeners who want a steady harvest of flavorful tomatoes from mid-summer to early fall. Indeterminate varieties require more maintenance—such as pruning and staking—but reward you with an extended season of fresh tomatoes.
Q: Are black tomatoes easy to grow?
A: Yes, black tomatoes like the Black Prince are generally easy to grow, especially for gardeners who are already familiar with heirloom or indeterminate varieties. While they require the usual tomato care—full sun, rich well-drained soil, consistent watering, and good airflow—they’re relatively hardy and well-suited to a range of climates. However, their thinner skin can make them more prone to splitting, and their darker coloration can make it trickier to tell when they’re ripe. With a little extra attention, though, they’ll reward you with unique, richly flavored tomatoes that truly stand out in the garden and kitchen.
Grow Your Own Black Prince Tomato Plant with Confidence
The journey from seed to harvest with the Black Prince tomato plant is not only rewarding—it’s empowering.
Whether you’re a seasoned grower or a curious beginner, this striking heirloom variety offers the perfect balance of beauty, flavor, and resilience.
With its deep mahogany tones and rich, complex taste, it’s no wonder the Black Prince is a favorite among gardeners and chefs alike.
Remember, success with this tomato starts with understanding its needs:
- Start your seeds indoors 6–8 weeks before the last frost, and transplant only after the soil warms up.
- Provide full sun, well-drained soil, and strong support, as this indeterminate plant can grow up to 6 feet tall or more.
- Water consistently and mulch to prevent splitting and maintain healthy soil moisture.
- Watch for signs of ripeness—deep coloration, slight softness, and sweet aroma—to harvest at peak flavor.
- Stay vigilant against common problems like blight, pests, and blossom end rot, and address them early to keep your plants productive.
Despite its exotic appearance, the Black Prince is not difficult to grow. With a bit of care and attention, you can enjoy a generous, ongoing harvest of some of the most flavorful tomatoes nature has to offer.
So, are you ready to get your hands in the soil and bring this heirloom gem to life?
Start your Black Prince tomato plant today and discover just how satisfying—and delicious—homegrown tomatoes can be.
