Quick Answer
To grow kale, spinach, and lettuce year-round in cold climates, use cold frames, hoophouses, or unheated greenhouses to extend the growing season. Choose varieties bred for cold hardiness and plant seeds in early spring or late summer for a fall harvest. Regular watering and fertilizing are essential.
Choosing the Right Varieties
For a year-round greens production in cold climates, select varieties that are bred for cold hardiness. For example, ‘Lacinato’ kale and ‘Space’ spinach are popular choices for their ability to withstand temperatures as low as 20°F (-7°C). ‘Loose-Leaf’ lettuce varieties such as ‘Red Oak’ and ‘Green Leaf’ are also suitable for cold climates. When selecting varieties, consider the specific growing conditions and microclimate of your area.
Building a Cold Frame
A cold frame is a low-cost and effective way to extend the growing season in cold climates. To build a cold frame, start with a wooden frame (approximately 4’ x 8’) and cover it with 6-8 mm of clear polycarbonate or glass. Add a south-facing slope to the frame to maximize sunlight exposure. Regularly monitor the temperature inside the cold frame and open it during the day to allow for ventilation.
Additional Tips for Success
To ensure success with year-round greens production, maintain a consistent watering schedule and fertilize regularly. Aim to provide 1-2 inches of water per week, either through rainfall or irrigation. Use a balanced fertilizer (e.g., 10-10-10 NPK) and follow the recommended application rates. Additionally, consider using row covers to protect your crops from extreme weather conditions and pests.
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