How to Grow Watermelons in New Zealand

Growing Watermelons From START TO FINISH – Tips and Tricks and Some Unusual Varieties

Juicy and refreshing, watermelons are a quintessential summer treat. While often associated with warm climates, it’s entirely possible to cultivate these delectable fruits in New Zealand’s diverse growing regions. By selecting the right varieties and following proper cultural practices, you can enjoy the rewarding experience of growing your own watermelons right in your backyard or garden. This comprehensive guide will equip you with the knowledge to successfully grow watermelons in New Zealand, from choosing the perfect cultivar to harvesting and storing your fresh produce.

Choosing the Right Watermelon Variety for New Zealand

The first step in your watermelon-growing journey is to select varieties well-suited to New Zealand’s climate and growing conditions. Factors like heat tolerance, disease resistance, and maturity time should be carefully considered. Here’s a quick comparison of some popular watermelon cultivars:

VarietySizeMaturity (Days)Climate SuitabilityNotes

Crimson Sweet	Large (16-24 lbs)	90-100	Warm to hot	Classic red flesh, high sugar content
Sugar Baby	Small (6-10 lbs)	75-85	Cool to warm	Ideal for cooler regions, sweet flavor
Charleston Gray	Large (20-30 lbs)	90-100	Warm to hot	Heat-tolerant, disease-resistant
Yellow Doll	Small (5-8 lbs)	70-80	Cool to warm	Yellow flesh, crisp texture

When selecting a watermelon variety, consider your region’s average summer temperatures and the length of the growing season.

Heat-Tolerant Varieties

In New Zealand’s warmer regions, such as Northland, Bay of Plenty, and Hawke’s Bay, heat-tolerant varieties like Crimson Sweet and Charleston Gray thrive. These watermelons can withstand high temperatures and still produce large, flavorful fruits. Crimson Sweet, with its classic red flesh and high sugar content, is a popular choice among home gardeners and farmers alike.

Cool Climate Varieties

For cooler areas like Canterbury, Otago, and Southland, consider smaller watermelon varieties like Sugar Baby and Yellow Doll. These cultivars have a shorter growing season and can tolerate cooler temperatures better than their heat-loving counterparts. Sugar Baby, for instance, is known for its sweet flavor and manageable size, making it an excellent option for smaller gardens or families.

Preparing the Soil and Planting

Proper soil preparation and planting techniques are crucial for establishing a strong foundation for your watermelon plants.

Watermelons thrive in well-draining, nutrient-rich soil with a pH range of 6.0 to 6.8. Raised beds or hills can help improve drainage and warmth, which is especially beneficial in cooler regions.

Soil Preparation

1. Start by removing any existing weeds or debris from your planting area.
2. Till or loosen the soil to a depth of 8-12 inches to allow for proper root development.
3. Incorporate well-aged compost or manure into the soil to improve fertility and water retention.
4. If necessary, adjust the soil pH by adding lime to raise it or sulfur to lower it.
5. Create raised beds or hills approximately 8-12 inches high and 4-6 feet apart.

Planting Techniques

• Direct Sowing: Plant watermelon seeds 1 inch deep and 2-3 feet apart after the last frost date when soil temperatures reach 70°F (21°C) or higher.
• Transplanting: For an earlier start, sow seeds indoors 4-6 weeks before the last frost date. Transplant seedlings outdoors after hardening off, spacing them 2-3 feet apart.
• Spacing: Proper spacing is crucial for watermelon vines to sprawl and develop fully. Allow 6-8 feet between hills or rows.

Caring for Watermelon Plants

Consistent care and maintenance are essential for ensuring your watermelon plants thrive and produce bountiful harvests.

Watermelons require consistent moisture, especially during fruit development. Inadequate watering can lead to poor fruit quality and reduced yields. On the other hand, overwatering can promote diseases and root rot.

Watering and Irrigation

• Water plants deeply, aiming for 1-2 inches of moisture penetration into the soil.
• Adjust watering frequency based on weather conditions and soil drainage. In hot, dry conditions, water every 5-7 days.
• Use drip irrigation or soaker hoses to deliver water directly to the roots, minimizing water loss through evaporation.

Mulching and Weed Control

Mulching is highly recommended for watermelon plants as it helps retain soil moisture, suppress weeds, and regulate soil temperatures.

• Apply a 2-4 inch layer of organic mulch, such as straw or wood chips, around the plants after the soil has warmed up.
• Regularly remove any weeds that manage to sprout through the mulch, as they can compete with your watermelon plants for nutrients and water.

Pest and Disease Management

While watermelons are generally hardy, they can be susceptible to certain pests and diseases in New Zealand. Monitor your plants regularly and take appropriate action to prevent or control infestations.

• Common pests: Aphids, cucumber beetles, and spider mites. Control with insecticidal soap or neem oil.
• Diseases: Powdery mildew, fusarium wilt, and anthracnose. Rotate crops, use disease-resistant varieties, and follow proper sanitation practices.

For severe infestations or disease outbreaks, consult a local agricultural extension office or nursery for advice on safe and effective control measures.

Harvesting and Storing Watermelons

Knowing when to harvest and how to properly store your watermelons is crucial for enjoying their peak flavor and texture.

Watermelons typically take 80-100 days to mature, depending on the variety and growing conditions. Look for these signs to determine when your fruits are ready for harvesting:

• The underside of the watermelon (where it rests on the ground) turns from greenish-white to creamy yellow.
• The curly tendril nearest the fruit turns brown and dries up.
• The watermelon produces a dull, hollow sound when tapped.

Harvesting Techniques

1. Use a sharp knife or pruning shears to cut the watermelon stem about 2-3 inches from the fruit.
2. Avoid lifting or carrying watermelons by the stem, as this can cause them to crack or bruise.
3. Harvest watermelons in the morning or evening when temperatures are cooler to prevent them from overheating.

Storage and Preservation

• Fresh watermelons can be stored at room temperature for up to 2 weeks or refrigerated for up to 4 weeks.
• For longer-term storage, consider pickling, freezing, or making watermelon jam or jelly with excess fruits.
• Dehydrated watermelon slices or chips also make a tasty and healthy snack option.

Conclusion

Growing watermelons in New Zealand is a rewarding endeavor that yields delicious and refreshing fruits. By following these steps – from selecting the right variety to properly caring for your plants and harvesting at the right time – you can enjoy the sweet taste of homegrown watermelons throughout the summer months. With a little patience and care, you’ll be able to savor the juicy rewards of your labor and maybe even inspire others to embark on their own watermelon-growing adventures.