Greenhouse Techniques Enable Yearround Strawberry Production

Imagine enjoying fresh, juicy, and sweet strawberries even during cold winter months. This is no longer an unattainable dream. Through greenhouse cultivation techniques, we can break seasonal limitations and achieve year-round strawberry production. But how can one successfully grow strawberries in greenhouses while obtaining ideal yields and quality? This comprehensive guide will help you master greenhouse strawberry cultivation.

The answer is affirmative. While strawberries naturally have a short growing season, greenhouse environmental controls allow us to simulate optimal climatic conditions, extending their growth cycle and even enabling year-round production. In the United States, California and Florida serve as primary strawberry production regions due to their warm climates. However, greenhouse solutions offer ideal alternatives for growers in other areas.

It's important to note that strawberry plants still require dormancy periods. Therefore, greenhouse cultivation plans must incorporate dormancy considerations. Additionally, while greenhouses provide protection, strawberry plants remain vulnerable to pests and diseases. Selecting disease-resistant varieties and implementing effective pest control measures are crucial.

Choosing appropriate strawberry varieties is essential for continuous production. Different cultivars exhibit distinct growth habits and fruiting periods. By selecting complementary varieties, growers can ensure harvests throughout different seasons.

• June-bearing strawberries: The most common type, typically producing concentrated yields in late spring/early summer for 2-3 weeks. Subcategories (early, mid, late-season) allow extended harvest windows.
• Everbearing strawberries: Capable of producing two or three annual crops under favorable conditions. While yields are lower than June-bearing types, their production period is longer. Suitable for mound cultivation in space-limited environments.
• Day-neutral strawberries: Unique varieties that continuously flower and fruit when temperatures remain between 35°F and 85°F. In greenhouses with temperature controls, they enable true year-round production. Note that fruits are typically smaller than other types.

Research from the University of Florida highlights 'Florida Radiance' (short-day variety) and 'Florida Beauty' (day-neutral) as excellent performers in commercial elevated greenhouses. For year-round supply, day-neutral varieties are ideal, while June-bearing types can supplement for larger fruits.

• Type: Warm-season crop
• Seed to harvest: 60-90 days
• Germination temperature: 65-70°F (18-21°C)
• Emergence: 2-3 weeks
• Optimal growth temperature: 60-80°F (15-27°C)
• Height: 12-16 inches (30-40 cm)
• Spread: 12-18 inches (30-45 cm), extended by runners
• Companion plants: Asparagus, beans, peas, rhubarb, spinach, lettuce, garlic, lupines
• Incompatible plants: Brassicas, nightshades, okra, roses, melons

Greenhouse strawberry production is straightforward when following these steps:

1. Propagation: Start with disease-free transplants or runners in clear containers with high humidity until root systems develop.
2. Soil preparation: Amend raised beds with organic matter and potassium-rich fertilizers to promote fruiting.
3. Spacing: Allow 18 inches (45 cm) between plants and 30 inches (76 cm) between rows.
4. Planting technique: Dig holes deep enough to accommodate roots without bending. Position crowns slightly above soil level to prevent rot.
5. Mulching: Apply mulch to regulate moisture and suppress weeds.
6. Container options: Use 6-inch (15 cm) diameter pots with multiple drainage holes, or hanging baskets for space efficiency.
7. Runner management: Remove most runners during fruiting season to direct energy toward production. Selectively root some runners for propagation.

• Source certified disease-free plants from reputable nurseries
• Apply organic liquid fertilizer biweekly during flowering
• Remove first-year flowers from June-bearing varieties to enhance subsequent yields
• Implement pollination assistance to prevent misshapen fruits
• Use straw or fiber mats for weed suppression and rot prevention
• Rotate plantings every three years to maintain vigor
• Reduce fertilization if green fruit bottoms indicate excess nitrogen

Combine different strawberry types to achieve continuous harvests. For example, plant mixtures of everbearing, June-bearing, and day-neutral varieties. Container cultivation facilitates moving plants in/out of greenhouses to provide necessary chilling periods. Note that greenhouse protection enables fruiting about one month earlier than outdoor plants.

Maintain consistent soil moisture (1.5 inches/week) without waterlogging. Morning irrigation at plant bases is ideal.

Provide well-drained, acidic soil (pH 5.5-7.0) rich in organic matter. Apply balanced organic fertilizer monthly, switching to high-potassium formulas during flowering.

Ensure 6-12 hours of daily sunlight. Supplement with grow lights during winter months.

Maintain 65-77°F (18-25°C) during flowering. Avoid exceeding 77°F (25°C) to prevent pollen damage. Implement cool periods (above 22°F/-6°C) to stimulate dormancy for June-bearing and everbearing types.

Greenhouses require manual pollination or introduction of bumblebees. Proper pollination ensures well-formed fruits.

Monitor for Japanese beetles, spider mites, slugs, and snails. Fungal diseases like powdery mildew and gray mold can be mitigated through sanitation and certified plant materials. Avoid planting near eggplants or tomatoes to prevent Verticillium wilt.

Replace strawberry plants after three seasons to maintain productivity and reduce pest/disease pressure. Rotate planting locations when possible.

Pick fruits approximately five weeks after flowering, every two days. Remove overripe berries promptly to prevent plant weakening. Harvest by pinching or cutting with 0.5-inch stems attached.

65-75% relative humidity is ideal for fruit set and development. Storage requires higher humidity (90-95%) at 32-36°F (0-2°C).

Vertical systems maximize space efficiency and improve airflow, reducing fungal risks. Special containers or hydroponic systems may be required.

In USDA zone 7 and below, maintain greenhouse temperatures above 22°F (-6°C) while providing necessary dormancy (except for day-neutral varieties).