Square watermelons have captured the imagination of fruit enthusiasts and gardeners alike. These uniquely shaped fruits, originating in Japan, offer both aesthetic appeal and practical benefits. To grow a square watermelon, gardeners place young, developing fruits inside specially designed molds that shape the melons as they mature.
These eye-catching creations serve as both decorative items and conversation starters. While square watermelons are primarily grown for their novelty and visual impact, they also offer practical advantages in storage and transportation. The flat sides make them easier to stack and less prone to rolling around during shipping.
Growing square watermelons requires careful attention and monitoring throughout the cultivation process. Gardeners must select the right variety of watermelon, provide optimal growing conditions, and apply the mold at the appropriate stage of fruit development. With proper technique and patience, home gardeners can produce these distinctive fruits in their own gardens.
Understanding Square Watermelons
Square watermelons are a unique and eye-catching fruit innovation. These geometric marvels showcase human ingenuity in agriculture and have captured global attention.
History and Origin
Square watermelons were first developed in Japan in the 1980s. Japanese farmers on Shikoku Island pioneered this unusual growing technique. They aimed to create a more storage-efficient fruit that could fit easily into Japanese refrigerators.
The method involves placing young watermelons into cube-shaped molds as they grow. As the fruit develops, it naturally takes on the square shape of its container. This process requires careful monitoring and precise timing to achieve the desired result.
Cultural Significance in Japan
In Japan, square watermelons are often seen as luxury items or gifts. Their unique shape and rarity make them prized for special occasions and corporate presents. These fruits can fetch high prices, sometimes selling for over $100 each.
Square watermelons represent Japanese values of innovation and aesthetic appeal in everyday objects. They showcase the culture’s attention to detail and commitment to solving practical problems in creative ways.
The fruits are often displayed in high-end department stores and fruit shops as works of art. This elevates them beyond mere produce to symbols of craftsmanship and ingenuity.
Modern Uses and Popularity
Square watermelons have gained popularity worldwide as novelty items. They’re frequently featured in social media posts and news articles, attracting attention for their unusual appearance.
Some farmers have expanded on the concept, creating heart-shaped watermelons and other geometric fruit designs. These unique fruits are popular for special events like weddings or as decorative centerpieces.
Despite their visual appeal, square watermelons are typically not eaten. They’re often harvested before fully ripe to maintain their shape, making them less sweet than traditional watermelons. Their primary value lies in their aesthetic qualities rather than their taste or nutritional content.
Pre-Planting Steps
Successful square watermelon cultivation begins with proper preparation. Careful seed selection, soil optimization, and climate considerations are essential for achieving the desired shape and flavor.
Selecting the Right Seeds
Choose high-quality watermelon seeds from reputable suppliers. Look for varieties known to produce smaller, compact fruits that are easier to shape into squares. Consider disease-resistant cultivars to improve plant health and yield.
Some gardeners opt for specialized square watermelon seeds, though these are not always necessary. Standard watermelon seeds can work well when paired with proper growing techniques and shaping methods.
Preparing the Soil
Watermelons thrive in well-draining soil rich in organic matter. Test the soil pH and aim for a range between 6.0 and 6.8. Amend acidic soil with lime or alkaline soil with sulfur as needed.
Incorporate compost or aged manure into the planting area to improve fertility and soil structure. This enhances water retention while preventing waterlogging. Add sand or perlite to heavy clay soils to increase drainage.
Create raised beds or mounds to further improve drainage and soil warmth. This technique is particularly beneficial in areas with cooler climates or heavy soils.
Understanding Climate Needs
Watermelons require warm temperatures and ample sunlight for optimal growth. They thrive in climates with long, hot summers and at least 6-8 hours of direct sunlight daily.
Soil temperature should be at least 70°F (21°C) for seed germination. Use black plastic mulch to warm the soil in cooler regions. This also helps retain moisture and suppress weeds.
Plan your planting schedule based on your local frost dates. Start seeds indoors 3-4 weeks before the last expected frost for an early start in cooler climates. In warmer areas, direct sowing is possible once soil temperatures are consistently warm.
Creating the Square Mold
Creating a proper square mold is crucial for growing square watermelons. The mold must be sturdy, transparent, and the right size to shape the fruit as it grows.
Materials and Tools Required
To build a square watermelon mold, you’ll need:
- 6 sheets of polycarbonate plastic, 8 inches square and 3/8 inch thick
- 4 gate hinges
- 2 hinged clasps
- Flat head machine screws and hex nuts
- 8-12 wood screws, 1 to 1.5 inches long
- Screwdriver
- Drill (optional)
Polycarbonate plastic is ideal due to its durability and transparency. It allows sunlight to reach the fruit while providing a rigid structure.
Steps to Build the Square Mold
Arrange 5 polycarbonate sheets to form a cube without a lid.
Attach the sides using gate hinges. Place two hinges on each vertical edge.
Secure the bottom piece to the sides using wood screws.
Attach hinged clasps to the top edges of two opposite sides.
Use the 6th polycarbonate sheet as a removable lid.
Drill small ventilation holes in the sides and lid if needed.
Ensure all edges are smooth to prevent damage to the watermelon. The mold should open easily for fruit inspection and harvesting.
Safety and Handling
Handle the polycarbonate sheets carefully to avoid cuts. Wear gloves when working with the material.
Ensure the mold is stable when placed in the garden. Secure it to the ground if necessary to prevent tipping.
Clean the mold thoroughly before each use. Disinfect with a mild bleach solution to prevent fungal growth.
Store the mold in a dry place when not in use to extend its lifespan. Inspect regularly for cracks or damage that could affect the watermelon’s growth.
Planting and Caring for Your Square Watermelon
Growing square watermelons requires careful attention to germination, transplanting, fertilization, and watering. Following proper techniques at each stage helps ensure healthy growth and development.
Germination Process
Start seeds indoors 4-6 weeks before the last frost date. Use seed trays filled with a well-draining potting mix. Plant seeds 1/2 inch deep and keep soil moist but not waterlogged.
Maintain temperatures between 70-80°F (21-27°C) for optimal germination. Seeds typically sprout within 3-10 days. Provide 14-16 hours of light daily once seedlings emerge.
Thin to the strongest seedling per cell when plants develop their first true leaves. Continue growing indoors until outdoor temperatures consistently reach 70°F (21°C).
Transplanting Seedlings
Prepare the garden bed with well-draining, fertile soil. Choose a sunny location that receives 6-8 hours of direct sunlight daily. Space plants 2-3 feet apart in rows 6 feet apart.
Harden off seedlings by gradually exposing them to outdoor conditions over 7-10 days. Transplant on a calm, overcast day to minimize stress.
Dig holes twice the size of the root ball. Place seedlings at the same depth they were growing in containers. Water thoroughly after planting to settle soil around roots.
Applying Fertilizer and Nutrients
Square watermelons require regular fertilization for optimal growth. Apply a balanced, water-soluble fertilizer (10-10-10) every 2-3 weeks during the growing season.
Side-dress plants with compost or aged manure when vines begin to run. Avoid over-fertilizing, as this can lead to excessive foliage growth at the expense of fruit production.
Supplement with calcium and magnesium if soil tests indicate deficiencies. These nutrients are crucial for proper fruit development and sweetness.
Watering Requirements
Consistent moisture is essential for square watermelon growth. Water deeply and regularly, providing 1-2 inches of water per week through rainfall or irrigation.
Increase watering frequency during fruit set and development. Reduce irrigation as fruits near maturity to concentrate sugars and improve flavor.
Use drip irrigation or soaker hoses to keep foliage dry and prevent fungal diseases. Mulch around plants to retain soil moisture and suppress weed growth.
Monitor soil moisture regularly, adjusting watering as needed based on weather conditions and plant growth stage.
Monitoring and Maintenance
Growing square watermelons requires vigilant care and attention to detail. Regular monitoring and proper maintenance are crucial for successful cultivation and shaping of these unique fruits.
Installing the Mold
Place the mold around the young watermelon when it reaches about the size of a baseball. Choose a sturdy, transparent plastic or glass mold to allow light penetration. Position the mold carefully to avoid damaging the vine or fruit. Secure the mold firmly to prevent shifting as the watermelon grows. Ensure proper ventilation by creating small holes in the mold to prevent moisture buildup and fungal growth.
Regular Check-ups and Adjustments
Inspect the growing watermelon every 2-3 days. Monitor its growth progress and shape development within the mold. Adjust the mold if necessary to maintain proper alignment. Check for any signs of stress on the vine or fruit. Ensure the watermelon receives adequate sunlight and air circulation. Maintain consistent soil moisture through regular watering, providing 1-2 inches of water per week.
Fertilize the plants every 2-3 weeks with a low-nitrogen, high-potassium fertilizer to promote fruit development. Prune excessive vine growth to direct nutrients towards fruit production. Remove any misshapen or stunted fruits to allow resources for the square watermelon.
Pest and Disease Control
Implement preventive measures to protect square watermelons from common pests and diseases. Install row covers or netting to deter insects like aphids and cucumber beetles. Monitor for signs of powdery mildew, a common fungal disease in watermelons. Apply organic fungicides if necessary.
Regularly inspect the leaves, stems, and fruit for any unusual discoloration or damage. Remove any infected plant parts promptly to prevent disease spread. Maintain proper spacing between plants to improve air circulation and reduce disease risk. Rotate watermelon crops annually to minimize soil-borne pathogens.
Harvesting Your Square Watermelon
Harvesting a square watermelon requires careful timing and technique. Proper methods ensure you can enjoy the unique shape and flavor of your square fruit.
Determining Ripeness
Check the underside of the watermelon for a yellow spot. This indicates it has been resting on the ground and is nearing ripeness. Tap the watermelon gently – a ripe one produces a hollow sound. The tendril closest to the fruit stem should be brown and dry.
Look for a dull appearance on the rind rather than a shiny one. Count the days since planting, as most varieties are ready to harvest 70-100 days after sowing. Square watermelons may ripen slightly faster due to their constrained growth.
Removing the Mold
Carefully open the mold once ripeness is confirmed. Unscrew or unclip the sides, depending on the mold design. Lift the top section gently to avoid damaging the fruit. Support the watermelon as you remove each side of the mold.
Inspect the fruit for any indentations or marks from the mold. Brush off any dirt or debris. Handle the square watermelon with care, as its shape makes it more susceptible to damage than round varieties.
Cutting and Storing
Cut the watermelon from the vine with clean, sharp pruning shears. Leave a short stem attached to prevent rot. Wipe the fruit with a damp cloth to remove any remaining dirt. Store whole square watermelons at room temperature for up to a week.
For longer storage, place them in the refrigerator for up to two weeks. When ready to eat, cut the watermelon into cubes or slices. The square shape allows for unique presentation options. Store cut pieces in an airtight container in the fridge for 3-5 days.