It is entirely possible to grow strawberries year-round in a greenhouse, providing a consistent supply that outdoor farming cannot match. This continuous production is achieved through Controlled Environment Agriculture (CEA), a method that precisely manages the growing conditions for the plants. A greenhouse overrides the natural seasonality of light, temperature, and weather, allowing biological processes to function optimally regardless of the climate outside. Controlling the environment transforms the strawberry from a seasonal crop into a perpetual one.
Selecting Strawberry Varieties for Continuous Harvest
The choice of strawberry variety is the fundamental decision for a year-round greenhouse operation. For continuous cultivation, growers rely on “Day-Neutral” or remontant varieties, which are genetically programmed to flower and fruit regardless of the length of the day. This is a significant biological advantage over traditional types.
This is in sharp contrast to “Short-Day” or June-bearing varieties, which initiate their flower buds only when daylight hours drop below a certain threshold, typically in the late summer or fall. Short-day varieties produce one concentrated harvest in the late spring or early summer, making them unsuitable for year-round production cycles. Day-neutral cultivars like ‘Albion’ or ‘Seascape’ are preferred because they maintain constant production as long as the temperature is kept within their preferred range.
Day-neutral plants produce smaller, more frequent harvests over a longer period, sometimes from spring until the first heavy frost in outdoor settings, or continuously inside a greenhouse. This continuous fruiting habit makes them the ideal choice for maximizing the efficiency and economic viability of a high-tech controlled environment.
Managing Greenhouse Climate for Year-Round Production
Achieving a year-round harvest requires precise, automated management of the greenhouse climate to meet the strawberry plant’s specific needs. Temperature is one of the most important factors, as it directly influences flowering, fruit set, and sugar development. Optimal daytime temperatures for active growth and fruit development generally range between \(18^{\circ}\text{C}\) and \(24^{\circ}\text{C}\) (\(64^{\circ}\text{F}\) to \(75^{\circ}\text{F}\)).
A temperature differential between day and night is also maintained to encourage proper plant physiology. Nighttime temperatures are typically dropped to a cooler range, around \(8^{\circ}\text{C}\) to \(13^{\circ}\text{C}\) (\(46^{\circ}\text{F}\) to \(55^{\circ}\text{F}\)), which helps trigger flower development and promotes the accumulation of sugars in the fruit. Consistent climate control prevents temperature extremes that can lead to misshapen fruit, poor flower formation, or plant stress.
Supplemental lighting is necessary to ensure consistent photosynthesis during the darker winter months or on cloudy days, overriding seasonal light limitations. High-efficiency LED grow lights are used to provide the necessary Daily Light Integral (DLI), which is the total amount of light received by the plants per day. For high yields, this DLI should be maintained in the range of 20 to 25 moles per square meter per day.
Humidity management is equally important, as strawberries are susceptible to fungal diseases in overly moist conditions. The ideal relative humidity (RH) for strawberries is maintained between \(60\%\) and \(75\%\). Modern greenhouses use ventilation, heating, and dehumidification systems to keep the humidity stable.
Many commercial operations also use carbon dioxide (\(\text{CO}_2\)) enrichment to boost growth rates and yields. By increasing the ambient \(\text{CO}_2\) concentration beyond the natural atmospheric level of about 400 parts per million, the rate of photosynthesis is significantly accelerated. This practice, combined with optimal light and temperature, allows the plants to maximize their energy production and subsequent fruit yield.
Modern Growing Systems for Intensive Cultivation
To maximize the use of expensive, climate-controlled greenhouse space, year-round strawberry production relies on soilless and high-density cultivation methods. Traditional soil is replaced with inert substrates such as coco coir, rockwool, or perlite. Using soilless media offers greater control over the root environment, allowing growers to precisely manage nutrient and water delivery.
Nutrients are delivered directly to the plants through closed-loop hydroponic systems, such as the Nutrient Film Technique (NFT) or, more commonly, a drip irrigation system. Drip systems deliver a carefully formulated nutrient solution, known as a fertigation solution, to each plant individually. This precision feeding ensures the plants receive a balanced supply of macro- and micronutrients, which is crucial for continuous fruiting.
A key factor in the economic viability of greenhouse cultivation is the implementation of vertical or tiered growing systems. Since strawberry plants are relatively short, they are often grown in elevated channels or gutters, known as tabletop systems, suspended about one meter above the ground. These systems allow growers to stack or rack multiple levels of plants, dramatically increasing the plant density per square meter of floor space and improving yields.
Vertical growing systems, which may use stacked columns or multi-level horizontal racks, can increase plant density to as much as 49 plants per square meter, compared to much lower densities in field production. This intensive cultivation, combined with the precise environmental and nutritional control, is what makes year-round greenhouse strawberry production a consistent and high-yielding agricultural system. The elevated nature of these systems also improves air circulation around the plants and places the fruit at a comfortable height for harvesting.