Icebox watermelons are a compact variety, typically weighing 5 to 15 pounds. Their manageable size makes them convenient for smaller households and ideal for fitting into a refrigerator, which is how they earned their name. They are also a popular choice for home gardeners with limited space, including those growing in containers, offering a practical alternative to larger varieties without compromising on flavor.
Getting Started: Variety, Site, and Soil
Selecting the right variety is the initial step, as “icebox” refers to a size rather than a specific type of watermelon. Popular varieties include ‘Sugar Baby’ (dark green rind, sweet red flesh) and ‘Bush Sugar Baby’ (compact vine). Other options are ‘Yellow Petite’ (yellow flesh) and seedless mini-watermelons like ‘Belmont’ and ‘Eclipse’.
Watermelons thrive in full sun, needing at least six hours of direct sunlight daily for optimal growth and fruit development. Good air circulation helps prevent fungal diseases. They prefer well-drained, sandy loam soil rich in organic matter. Amending the soil with compost or aged manure before planting enhances fertility and drainage. The ideal soil pH for watermelons ranges from slightly acidic to neutral, between 6.0 and 7.5.
Planting and Early Care
Plant icebox watermelons in late spring or early summer, after all frost danger has passed and when soil temperature consistently reaches 70°F (21°C) or higher. Seeds can be direct-sown outdoors 1/2 to 1 inch deep, 4 to 6 seeds per “hill,” thinning to 2 or 3 seedlings later. Alternatively, start seedlings indoors in larger pots and transplant them once they have at least two true leaves and soil temperatures are sufficient.
Watermelon vines need ample space to spread; icebox varieties generally require 3 to 5 feet between plants, or 2 to 3 feet if planted in hills. Water young plants to keep the soil moist but not waterlogged. Protecting them from early pests or cold snaps with row covers helps establishment during their early growth phase.
Ongoing Growth and Maintenance
Consistent, deep watering is important for watermelons, especially from planting through fruit development, as their fruit is about 92% water. Plants need 1 to 2 inches of water per week, applied at the base of the vine to avoid wetting leaves and preventing fungal issues like powdery mildew. Drip irrigation or soaker hoses effectively deliver water directly to the root zone, encouraging deeper growth. Reducing water as fruits approach maturity can help concentrate sugars for a sweeter melon.
Watermelons need a steady supply of nutrients. Adjust fertilization as the plant progresses through its growth stages. Initially, apply a balanced fertilizer or one higher in nitrogen to support vegetative growth. Once flowering begins and fruits form, the plant needs less nitrogen and increased phosphorus and potassium for fruit development and sweetness. Organic options like diluted fish emulsion, compost tea, or aged manure can be applied every few weeks.
Watermelon plants produce separate male and female flowers, requiring pollinators for fruit set. Bees are the primary pollinators, transferring pollen from male to female flowers. Encouraging bee activity by planting pollinator-friendly flowers nearby can improve fruit production. While vines naturally sprawl, trellising icebox watermelons can save space, though this requires supporting the developing fruit.
Harvesting Icebox Watermelons
Knowing when to harvest an icebox watermelon is important for optimal sweetness and flavor. Several indicators signal ripeness:
The ground spot, where the melon rests on the soil, changes from white or pale green to a creamy or deep yellow.
The rind loses its bright sheen, becoming dull or waxy.
The tendril closest to the fruit stem dries out and turns brown.
Tapping the melon produces a hollow, muffled sound (unripe melons sound more solid).
When harvesting, cut the watermelon from the vine with a sharp knife or shears, leaving a short stem attached. Avoid pulling or twisting the melon off the vine, which can damage the fruit or plant.
Troubleshooting Common Issues
Poor fruit set often stems from insufficient pollination. Watermelon flowers require bees to transfer pollen between male and female blooms. If natural pollinators are scarce, hand-pollination can be performed using a small brush or a male flower itself. Misshapen fruits can result from incomplete pollination or inconsistent watering.
Fungal diseases like powdery mildew appear as a white, powdery growth on leaves. Manage them by ensuring good air circulation, watering at the base of the plant to keep foliage dry, and applying appropriate fungicides if necessary. Fusarium wilt causes wilting and yellowing of foliage; mitigate it by using resistant varieties, practicing crop rotation, and ensuring well-draining soil.
Common garden pests include aphids and cucumber beetles. Aphids are sap-sucking insects that cause leaf curling; dislodge them with a strong jet of water or treat with insecticidal soap. Cucumber beetles chew on leaves and transmit bacterial wilt; control them with hand-picking or neem oil. Maintaining overall plant health through proper watering and fertilization increases a plant’s resilience to pest and disease pressures.