Winter can be a challenging season for gardeners, but a greenhouse provides an excellent solution to keep the harvest going. With the right crops and care, a greenhouse can turn the coldest months into a productive period. This guide will explore ten plants that are particularly well-suited to winter greenhouse cultivation, detailing their growth requirements and benefits.
10 Best Plants to Grow in a Greenhouse in Winter
1. Microgreens
Microgreens are ideal for greenhouse cultivation in winter due to their minimal space requirements and rapid growth cycle, often ready for harvest in just 2-3 weeks. They thrive in temperatures between 60°F and 75°F and can grow in low light conditions, although supplemental lighting can boost their growth. Microgreens are a nutrient-dense choice, providing a fresh, flavorful addition to meals during the winter months.
2. Radishes
Radishes are a fast-growing crop, typically ready for harvest within 3-4 weeks. They can tolerate temperatures as low as 40°F but prefer a range of 50°F to 65°F. Radishes can manage in low-light conditions, making them a practical winter greenhouse crop. They require well-drained soil and consistent moisture for optimal growth and crisp, flavorful roots.
3. Garlic
Garlic is typically planted in the fall and requires a long growing season, with a harvest in late spring or early summer. It can withstand winter temperatures and benefits from the stable environment of a greenhouse. Garlic needs a period of cold for successful bulb development, with temperatures around 32°F to 50°F being ideal. It requires well-drained soil and moderate watering.
4. Onions
Onions can be started in the winter for an early summer harvest. They prefer cooler temperatures, around 35°F to 55°F, and can be grown in pots or directly in the ground. Onions require 6-8 hours of sunlight daily, so supplemental lighting may be necessary during the shorter winter days. They take approximately 100-175 days to mature, depending on the variety.
5. Broad Beans
Broad Beans are hardy and can be sown in late fall for an early spring harvest. They can tolerate temperatures as low as 15°F, making them suitable for winter greenhouses. Broad beans require 80-100 days to mature and need well-drained soil and regular watering. They benefit from being planted in a sunny spot in the greenhouse.
6. Winter Salad Greens (like mizuna, mustard greens)
Winter salad greens such as mizuna and mustard greens can grow well in cooler temperatures, typically between 40°F and 60°F. They are quick growers, often ready to harvest in 4-6 weeks. These greens prefer at least 4 hours of sunlight daily and moist, well-drained soil. They can be continually harvested for a steady supply of fresh greens.
7. Leeks
Leeks are hardy and can be overwintered for an early spring harvest. They thrive in temperatures between 45°F and 75°F and take about 100-120 days to mature. Leeks require full sunlight and rich, well-drained soil. They benefit from regular watering and mulching to maintain soil moisture and temperature.
8. Turnips
Turnips grow well in cool temperatures, ideally between 40°F and 70°F. They take around 30-60 days to mature, depending on the variety. Turnips need at least 4-6 hours of sunlight daily and fertile, well-drained soil. Regular watering is necessary for even root development and to prevent woodiness.
9. Brussels Sprouts
Brussels Sprouts can be started in the winter for a spring harvest. They prefer cooler temperatures, around 45°F to 75°F, and require a long growing season, typically 100-200 days. Brussels sprouts need full sunlight and nutrient-rich, well-drained soil. They benefit from regular feeding and consistent moisture.
10. Pak Choi
Pak Choi tolerates cooler temperatures and can be grown throughout the winter in a greenhouse. It prefers temperatures between 50°F and 70°F and matures in about 30-45 days. Pak Choi requires at least 3-5 hours of sunlight daily and moist, fertile soil. It’s a great choice for continuous harvesting as it regrows quickly after cutting.
Tips for Greenhouse Growing in the Winter
Temperature Control
Maintaining an appropriate temperature is crucial for winter greenhouse crops. A thermometer helps in monitoring, and heating systems may be necessary to keep the environment within the ideal range for each plant.
Lighting
Due to shorter daylight hours in winter, supplementing with grow lights ensures plants receive enough light for proper growth and development.
Ventilation
Good air circulation is key to preventing fungal diseases and maintaining a healthy growing environment. Utilize vents or fans for effective air movement.
Soil Management
High-quality soil is essential, and using pots or raised beds can offer better control over soil conditions, which is particularly important in winter.
Cleaning Your Greenhouse
A clean greenhouse is vital for healthy plant growth. Regularly remove plant debris, sanitize surfaces, and maintain good hygiene to prevent disease and pest problems.
With these plants and tips, your greenhouse can be a vibrant and productive space even during the cold winter months, providing fresh produce and the joy of gardening year-round.
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.