How to Grow Watermelon in New Jersey

Selecting the Right Watermelon Variety

Choosing the appropriate watermelon variety is crucial for successful cultivation in New Jersey's climate. Factors to consider include days to maturity, disease resistance, and flavor profile. Here's a comparison of some popular watermelon varieties well-suited for the region:

VarietyDays to MaturityDisease ResistanceFlavor

Sugar Baby	75-85 days	Anthracnose, Fusarium Wilt	Sweet, crisp
Crimson Sweet	85-90 days	Fusarium Wilt	Sweet, juicy
Charleston Gray	90-100 days	Anthracnose, Fusarium Wilt	Sweet, flavorful
Millennium	90-95 days	Anthracnose, Fusarium Wilt	Sweet, crisp
Sangria	90-100 days	Fusarium Wilt	Sweet, aromatic

Heat-Tolerant Varieties

New Jersey's summers can be hot and humid, making heat-tolerant watermelon varieties a smart choice. Varieties like Sugar Baby, Crimson Sweet, and Charleston Gray are known for their ability to thrive in warm conditions, producing sweet and juicy fruits even during the hottest months.

Disease-Resistant Varieties

To combat common watermelon diseases in the region, consider disease-resistant varieties. Millennium and Charleston Gray, for example, offer resistance to anthracnose and fusarium wilt, two prevalent fungal diseases that can significantly impact plant health and yield.

Preparing the Planting Site

Proper site preparation is essential for watermelon cultivation. Begin by conducting a soil test to determine the nutrient levels and pH balance of your soil. Based on the test results, amend the soil with compost, aged manure, or a balanced fertilizer to provide the necessary nutrients for optimal plant growth.

Soil Testing and Amendments

Soil testing is a crucial step that should not be overlooked. It provides valuable information about your soil's fertility and pH levels, allowing you to make informed decisions about the amendments needed for watermelon cultivation. Consider sending a soil sample to your local extension office or using a reliable at-home soil testing kit.

Once you have the soil test results, amend the soil accordingly. Watermelons thrive in well-draining, nutrient-rich soil with a pH range of 6.0 to 6.8. If your soil is deficient in certain nutrients or has an unsuitable pH level, incorporate the recommended amendments to create an ideal growing environment.

Raised Beds and Drainage

Watermelons require excellent drainage to prevent root rot and other moisture-related issues. Raised beds are an effective solution, as they improve soil drainage and provide a controlled environment for plant growth. Construct raised beds using untreated wood or raised bed kits, ensuring a depth of at least 8 to 12 inches for sufficient root growth.

Proper drainage is also essential for watermelon cultivation. If your garden area has poor drainage, consider creating raised beds or installing drainage systems, such as perforated pipes or French drains, to direct excess water away from the planting area.

Planting and Caring for Watermelon Plants

Once you've prepared the planting site, it's time to sow your watermelon seeds or transplant seedlings. Here are some key considerations for successful planting and care:

• Planting Time: In New Jersey, it's best to plant watermelons after the last frost date, typically in late May or early June, when soil temperatures reach at least 70°F.
• Spacing: Watermelons require ample space for their vining growth habit. Space plants 3 to 4 feet apart in rows spaced 6 to 8 feet apart.
• Care Instructions:
  • Water regularly, providing about 1 to 2 inches of water per week, especially during fruit development.
  • Mulch around the plants to retain moisture and suppress weeds.
  • Fertilize with a balanced fertilizer or compost tea every 4 to 6 weeks during the growing season.
  • Prune off any unnecessary vines or leaves to improve air circulation and reduce disease risk.
  • Support developing watermelons with a piece of wood or cardboard to prevent rot and soil contact.

Direct Seeding vs. Transplanting

You can choose to either direct seed watermelon seeds into the garden or transplant seedlings started indoors or purchased from a nursery. Direct seeding is simpler and avoids potential transplant shock, but transplanting seedlings can give your watermelons a head start on the growing season.

If you opt for direct seeding, plant seeds 1 inch deep and about 2 feet apart, thinning out the weaker seedlings once they emerge. For transplanting, harden off the seedlings gradually before planting them in the garden at the recommended spacing.

Watering and Mulching

Consistent moisture is crucial for watermelon plants, especially during flowering and fruit development stages. Aim to provide about 1 to 2 inches of water per week, adjusting as needed based on weather conditions and soil moisture levels.

Mulching around the plants with a 2 to 4-inch layer of organic mulch, such as straw or shredded leaves, helps retain soil moisture, suppress weeds, and regulate soil temperature. Replenish the mulch as needed throughout the growing season.

Pest and Disease Management

Like any crop, watermelons are susceptible to various pests and diseases that can impact plant health and yield. Here's a table highlighting some common issues and their control methods:

Pest/DiseaseDescriptionControl Methods

Aphids	Small, soft-bodied insects that suck plant sap	Insecticidal soap, neem oil, ladybugs (biological control)
Cucumber Beetles	Yellow or striped beetles that feed on leaves and fruit	Row covers, organic insecticides (pyrethrins, spinosad)
Spider Mites	Tiny spider-like mites that cause leaf stippling and webbing	Insecticidal soap, neem oil, predatory mites (biological control)
Fusarium Wilt	Fungal disease causing wilting and plant death	Resistant varieties, crop rotation, fungicides
Anthracnose	Fungal disease causing leaf spots and fruit rot	Resistant varieties, fungicides, good sanitation
Powdery Mildew	Fungal disease causing white, powdery growth on leaves	Fungicides, good air circulation, resistant varieties

Identifying and Controlling Pests

Regular monitoring and early detection are key to controlling watermelon pests. Inspect your plants frequently for signs of insect activity, such as chewed leaves, sticky residue, or webbing. Once identified, implement appropriate control methods promptly.

For aphids, use insecticidal soaps or neem oil, or introduce beneficial insects like ladybugs for biological control. Cucumber beetles can be managed with row covers during the early growing season or organic insecticides like pyrethrins or spinosad. Spider mites are effectively controlled with insecticidal soaps, neem oil, or predatory mites.

Preventing and Treating Diseases

Disease prevention starts with selecting resistant varieties and practicing good cultural practices, such as crop rotation, proper spacing, and timely removal of infected plant material. Maintaining good air circulation and avoiding overhead watering can also help prevent fungal diseases.

If disease strikes, employ appropriate treatment methods. For fusarium wilt, rely on resistant varieties and crop rotation, as there are no effective fungicides. Anthracnose and powdery mildew can be managed with fungicides, along with good sanitation practices like removing and destroying infected plant material.