Growing strawberries successfully outside of their native temperate climate is challenging, especially in a tropical environment like Hawaii. Standard varieties require winter dormancy and significant chilling hours that the islands’ mild climate does not provide. By selecting specialized cultivars and adjusting the growing environment, it is possible to achieve a sustained harvest of fresh, high-quality berries. Success requires adapting the growing method to manage the heat, intense humidity, and year-round pressure from tropical pests and diseases.
Choosing Heat-Tolerant Strawberry Varieties
The most common failure point is selecting a temperate variety, which relies on cold to stimulate flowering. Gardeners in Hawaii must focus on day-neutral or everbearing types, which flower and fruit continuously as long as temperatures remain acceptable. These varieties bypass the need for a winter chill, allowing for perpetual production in the mild Hawaiian climate.
Day-neutral varieties like ‘Seascape’ are recommended for their ability to set fruit regardless of day length and their heat tolerance. Other cultivars known to perform well in warm climates include ‘Chandler,’ ‘Eversweet,’ and ‘Sweet Charlie’. While these varieties tend to produce smaller berries, they offer the consistency necessary for a year-round harvest. Focusing on specialized cultivars directs the plant’s energy toward fruiting.
Preparing the Growing Environment
The high rainfall and the unique composition of Hawaiian soil make proper drainage a requirement for strawberry health. Raised beds or containers are necessary because they prevent waterlogging and combat the poor drainage of volcanic and compacted clay subsoils. A growing medium composed of organic matter like compost, coir, or peat moss is important, as this improves aeration and moisture retention.
Strawberries thrive in a slightly acidic environment, ideally with a soil pH between 5.8 and 6.2. While many volcanic soils are naturally acidic, a soil test is recommended to determine if amendments are needed. If the soil proves too acidic, ground limestone or coral can be applied to raise the pH. Conversely, if the soil is alkaline, incorporating peat moss or sulfur can help lower it, ensuring optimal nutrient availability for the plant.
The intense tropical sun, particularly at lower elevations, requires careful consideration of planting location. Although strawberries need six to eight hours of direct sunlight for maximum productivity and flavor, excessive heat can suppress flowering and damage developing fruit. The ideal microclimate involves a location that receives bright morning sun but is protected from the harshest afternoon rays, perhaps by a taller companion plant or a light shade cloth. This strategic placement minimizes heat stress, which can otherwise cause the plants to cease flower production.
Managing Pests and Tropical Fungal Issues
Hawaii’s consistent warmth and high humidity create an environment conducive to pest and fungal problems. Fungal diseases are the primary threat, with Botrytis (gray mold) and Anthracnose being issues that thrive in moist, humid conditions. Cultural controls are the first line of defense against these pathogens.
Maximizing air circulation around the plants is important to reducing the moisture that fungi require to flourish. This is achieved by avoiding overhead watering and utilizing drip irrigation directed only at the soil level. Garden sanitation is important, involving regularly removing any dead foliage, fallen fruit, or plant debris that can harbor fungal spores and provide shelter for pests.
Tropical pests like slugs and snails are a problem, especially since they can carry the Rat Lungworm parasite, making control a food safety concern. Simple, non-chemical methods like copper barriers or beer traps are effective for home gardeners. For pests such as the spotted winged drosophila, prompt harvesting and physical barriers like fine mesh netting are the most practical defense for small-scale operations.
Year-Round Care and Harvesting
The care regimen for strawberries in Hawaii is continuous. The plants require consistent moisture, especially during fruiting, but the soil should never be saturated to prevent root rot and fungal infection. Watering in the early morning allows the foliage to dry completely before nightfall, which discourages the development of fungal pathogens.
The plants deplete soil nutrients faster, requiring frequent fertilization. Applying a balanced, slow-release organic fertilizer every four to six weeks sustains the plant’s production cycle. Runner management is another continuous task. Runners must be regularly pruned to redirect the plant’s energy toward producing fruit. Allowing too many runners to establish will reduce berry yield and create a dense canopy that traps moisture.