Step-by-Step: How to Grow Black Diamond Watermelons


Black Diamond Watermelons

Discover the delight of growing Black Diamond Watermelons in your garden. Learn essential tips on planting, caring for, harvesting, and storing this large, juicy fruit for the best summer treat. Make your summer memorable with the sweet and refreshing taste of Black Diamond Watermelons.

Black Diamond Watermelons are widely known for their large size, hard rind, and sweet, juicy red flesh. If you’re considering planting and growing Black Diamond watermelons, here are some essential tips:

Essential Tips For Growing Black Diamond Watermelons

1. Seeds and Starting Indoors: Start your seeds indoors about 3-4 weeks before the last frost date. This gives them a good start and helps ensure they produce fruit before the end of the growing season.

2. Planting and Space Requirements: Black Diamond Watermelons require a lot of space to grow. When transferring your seedlings outdoors, ensure you have at least 6-8 feet of space between each plant. The soil should be rich in organic matter and well-draining.

3. Sun and Water Requirements: Watermelons thrive in full sun and need plenty of water, especially during dry periods. However, try to water at the base of the plant to avoid wetting the leaves and potentially spreading disease.

4. Pollination: Watermelons need bees for pollination, so try to attract them to your garden with various flowering plants. If you have a small number of plants or notice low bee activity, you might consider hand pollinating by gently rubbing a male flower (one without a tiny fruit at the base) onto a female flower (one with a small fruit at the base).

5. Pests and Diseases: Common watermelon pests include aphids, cucumber beetles, and vine borers. Look for signs of these and take action if you see them. Diseases can include fungal infections like powdery mildew and bacterial wilt. Crop rotation and proper watering techniques can help prevent these.

6. Harvesting: Black Diamond Watermelons usually take around 70-90 days to reach maturity from planting. Signs that your watermelon is ready to harvest include a dull skin appearance and a cream or yellow spot where the fruit rests on the ground. A dried tendril (the curly green part connected to the fruit from the vine) is another good indicator of ripeness.

7. Seed Saving: If you want to save seeds for next year, choose a ripe and healthy watermelon, remove them, wash them, and let them dry before storing them.

Remember, growing watermelons can be challenging, especially if it’s your first time, but with care and attention, you’ll be rewarded with sweet, juicy fruit.

Propagating Black Diamond Watermelon

Propagation of Black Diamond watermelons requires high-quality seeds or seedlings, choosing a suitable planting location with good soil quality and proper drainage, following proper watering and fertilization techniques, using trellises or supports, monitoring for pests and diseases, and taking appropriate action if necessary.

To grow this heirloom melon successfully, sow the seeds indoors four weeks before the last frost date, as Black Diamonds require a long growing season of at least 80 days.

Organic matter should be added to the soil to improve moisture retention and drainage. Secondary key terms used: black diamond watermelon, vine, planting, organic matter, heirloom melon, sow, gardening.

Growing Black Diamond Watermelon in Pots

Growing Black Diamond watermelons in pots require careful attention to detail. To get started, select a suitable container providing ample space for the melon vine to grow. Choose a high-quality potting mix with good drainage to keep the soil moist but not waterlogged.

Watermelon seeds or seedlings should be planted at least an inch deep into the soil, and you should avoid overwatering as it can lead to root rot. Ensure that your pot is placed in a location with total sun exposure and optimal temperature for growth.

Also, proper fertilization techniques will encourage healthy plant growth and fruit production, while monitoring for pests and diseases will help maintain plant health.

Requirements for Growing Black Diamond Watermelons


Pay close attention to the melon’s growing conditions to ensure an abundant harvest of Black Diamond watermelons with a dark green rind and sweet red flesh packed with vitamin C and potassium. Full sun is essential for optimal growth; hence a bright and sunny spot with good drainage will do the trick.

Raised garden beds or mounds provide excellent drainage options for these heirloom melons. Avoid planting in windy spots as it can damage the delicate vines that tendril out from the main stem.


Ensuring good drainage and a pH range of 6.0-6.8 in the soil is vital for successful Black Diamond watermelon growth. Preparing the ground with organic matter like compost or aged manure beforehand can help achieve optimal conditions. Adding sand or perlite is recommended to improve drainage if you have heavy clay soils.

Planting in areas where standing water isn’t an issue is also essential. Regularly testing the soil can maintain optimal nutrient levels for healthy plant growth.


Proper watering is vital for the growth of black diamond watermelons. These heirloom melons thrive consistently and are adequately watered throughout the growing season. Underwatering can lead to small fruits with reduced sweetness and nutritional value.

On the other hand, overwatering can cause root rot and fungal diseases that may stunt their growth and reduce yield.

Drip irrigation systems or soaker hoses are some of the best ways to efficiently provide much-needed moisture to these vines while avoiding wetting their foliage excessively. Consider mulching around your plants to retain moisture in the soil.


For the successful growth of your heirloom black diamond watermelon variety, it is essential to maintain a temperature range of between 70-85°F during the day and above 60°F at night.

Extremely high temperatures above 95°F can cause sun scorch on the fruit while low temperatures below 50°F will stunt plant growth. A great way to ensure optimal temperature for your black diamond melon is by growing them in a greenhouse or in warmer climates.

Black Diamond Watermelon Care

Black Diamond watermelons are one of the best ways to satisfy your snack cravings while getting much-needed vitamin C, potassium, and sweetness. You can start growing them by sowing black diamond watermelon seeds indoors 3 weeks before the last frost date or directly outside after the later frost date when the soil temperature reaches at least 65°F.

After germination, transplant seedlings to a location with good drainage and full sun exposure, and add compost or peat to enrich organic matter in the soil. Provide consistent watering through drip irrigation daily for an inch of moisture or more if needed.

Protect them from pests like melon aphids, cucumber beetles, vine borers, squash bugs, stem blight, powdery mildew, and downy mildew with neem oil spray or insecticidal soap spray every two weeks until maturity when tendrils near the fruit wither away.

Harvesting should be done when Black Diamond Watermelons reach maturity with a deep yellowish spot on their underside indicating ripeness.


To ensure proper growth and yield of your black diamond watermelons, it’s essential to fertilize them using an ideal balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium. Over-fertilizing can lead to excessive vegetative growth instead of fruit production.

The best way to apply fertilizer is at the base of the plant while ensuring even distribution by watering it immediately. It’s always good practice to conduct regular soil testing to identify any lack of specific nutrients in your soil.

Pests to Watch Out For

Growing Black Diamond Watermelons can be a rewarding experience if done correctly. However, various pests can attack the plant and ruin your harvest. The most common pests to watch out for are aphids, cucumber beetles, and squash bugs.

Aphids suck sap from the leaves, causing them to wilt and turn yellow. Cucumber beetles feed on the watermelon plant’s leaves, flowers, and fruits, while squash bugs pierce the stem, causing it to wilt and eventually die.

To prevent these pests from attacking your Black Diamond Watermelons, it is recommended to use natural pest control methods like neem oil or insecticidal soap regularly.

Cucumber Beetles

Cucumber beetles can be a big problem when growing Black Diamond watermelons. These pests can cause damage to the plants and reduce the yield of your crop. To prevent cucumber beetle infestations, it is essential to monitor your plants regularly and take action as soon as you see any signs of damage.

You can use insecticidal sprays or organic methods like row covers to keep these beetles away from your plants. It is also essential to practice good sanitation by removing any weeds or plant debris that may attract these pests.

With proper care and attention, you can successfully grow healthy Black Diamond watermelons without the threat of cucumber beetle damage.


Harvesting Black Diamond Watermelons is an essential step as improper timing may lead to either under-ripe or over-ripe fruits. Here are some steps and tips for harvesting these watermelons:

1. Check the Field Spot: The field spot is part of the watermelon that lays on the ground while it grows. Over time, it changes from white to a creamy yellow or light orange color. This color change is a sign that the watermelon is ripe.

2. Tap the Melon: Give the watermelon a tap. If it’s ripe, it should make a hollow sound. The fruit may not be ripe if the sound is dull.

3. Check the Tendrils: Tendrils are the curly, pigtail-like structures on the vine near the watermelon. When these tendrils near the fruit stem dry out and turn brown, it is often a good sign that the watermelon is ripe.

4. Observe the Color and Shape: As Black Diamond Watermelons mature, their color becomes a bit duller and the overall shape of the fruit becomes uniform. If the watermelon is shiny or if there are irregularities in its shape, it might not be ripe.

5. Size and Days since Planting: Black Diamond Watermelons are generally quite large when mature – often around 30-50 lbs. Also, keep track of the days since planting. Black Diamond Watermelons generally take 70-90 days to mature from the time of planting.

Once you’ve determined that your Black Diamond Watermelon is ripe, you can harvest it by cutting the stem close to the fruit with a sharp knife or pruners. Handle your harvested watermelons carefully to avoid bruising or damaging the fruit.

It’s worth mentioning that determining the exact right time to harvest can be somewhat tricky, and you may need to rely on a combination of these signs to make your best judgment.


Storing Black Diamond Watermelons properly can extend their shelf life and preserve their quality. Here’s how you can store these watermelons:

1. Room Temperature Storage (Pre-Cut): If your watermelon is whole and hasn’t been cut, it can be stored at room temperature. Uncut watermelons can be kept for up to 10 days, but try to consume them as soon as possible for the best flavor.

2. Refrigeration (Cut Watermelon): Once cut, watermelons should be stored in the refrigerator to keep them fresh. Wrap the cut pieces in plastic wrap or store them in an airtight container. Cut watermelon can last about 3-5 days in the fridge.

3. Freezing: Watermelon can also be frozen, although this can alter the texture, making it mushier when thawed. This can work well if you use watermelon in smoothies or other recipes. To freeze, remove the rind and cut the watermelon into small pieces or use a melon baller.

Freeze the pieces on a baking sheet lined with parchment paper. Once frozen, transfer the pieces to a zip-top bag or airtight container. Frozen watermelon should be used within 9-12 months for best quality.

General Tips:

  • Always wash your watermelon before cutting it to remove any potential dirt or bacteria on the skin that could be transferred to the inside when cutting.
  • Don’t store your watermelon with ethylene-producing fruits like apples and bananas, as this can cause the watermelon to over-ripen and deteriorate faster.
  • Keep your watermelon away from other strong-smelling foods. Watermelon can absorb other flavors and odors, which may affect its taste.

Remember, the best way to enjoy a Black Diamond Watermelon is when it’s fresh. These storage methods can help maintain quality, but the flavor is always best when consumed shortly after harvesting.


Growing Black Diamond Watermelons can be a fun and rewarding experience. You can produce high-quality watermelons perfect for culinary and medicinal purposes with the proper techniques and care. Whether you are a seasoned gardener or just starting, our comprehensive guide on Mastering Black Diamond Watermelon

Growing will help you achieve success in growing these delicious fruits. From soil preparation to companion planting, harvesting to storage, we have covered every aspect of Black Diamond Watermelon growing. So why wait? Start your journey to becoming a master watermelon grower today!