Strawberries, traditionally a temperate crop, can be grown in hot weather, but the quality and quantity of the fruit suffer noticeably. While the plant is resilient and can survive high temperatures, successful cultivation requires managing the environment to mitigate heat stress. Harvesting sweet, sizable fruit when temperatures climb depends on balancing the plant’s preference for cooler conditions with the realities of a warmer climate.
The Strawberry’s Ideal Climate Profile
Strawberries thrive in a moderate environment, preferring a distinct difference between daytime and nighttime temperatures. For optimal growth and photosynthetic activity, the daytime temperature range is generally between 68 and 75 degrees Fahrenheit (20–24°C). A significant drop in temperature overnight is particularly important for fruit flavor and growth, with ideal nighttime temperatures between 50 and 54 degrees Fahrenheit (10–12°C). If night temperatures rise above 60 to 65 degrees Fahrenheit (16–18°C), the fruit’s sugar-acid ratio can be negatively impacted.
Physiological Effects of Excessive Heat
When temperatures consistently exceed 86 degrees Fahrenheit (30°C), the strawberry plant experiences significant heat stress that impairs its reproductive functions. This stress reduces flower count and fruit set, as high air temperatures directly reduce pollen viability, leading to poor pollination. Elevated heat forces the plant into thermal dormancy, where it grows leaves and runners but stops initiating new flowers, severely limiting yield. Heat stress also increases the plant’s respiration rate, causing it to consume stored energy faster than it can produce it. Fruit that develops in extreme heat is often smaller, lighter, and exhibits inferior color.
Cultivation Strategies for Heat Management
Managing the immediate environment is the most effective way to mitigate high temperatures. Applying shade cloth (30% to 50% coverage) reduces solar radiation and lowers ambient air temperature, protecting plants when temperatures exceed 80 degrees Fahrenheit. Proper irrigation is crucial for both hydration and cooling the root zone. Short, repeated bursts of irrigation can be used as a cooling method when temperatures exceed 86 degrees Fahrenheit (30°C), lowering the root zone temperature and alleviating leaf transpiration. Applying a thick layer of organic mulch, such as straw, also insulates the soil and helps keep the crowns and shallow roots cooler.
Selecting Heat-Tolerant Strawberry Varieties
Choosing the right cultivar is a foundational step for successful strawberry cultivation in hot climates. Varieties are categorized by fruiting habits, including June-bearing, everbearing, and day-neutral types. While day-neutral varieties, such as ‘Seascape,’ produce fruit continuously, they sometimes yield the lowest total berry weight in hot regions. June-bearing varieties often include cultivars successfully adapted for warmer climates. Specific varieties known for heat tolerance and good performance in hot, semi-arid regions include:
- Chandler
- Camarosa
- Albion
- Sweet Charlie
These cultivars handle high daytime temperatures well and often possess lower chilling requirements, making them suitable for regions with mild winters.