Can kale survive winter?
Written by
Tina Carter
Reviewed by
Prof. Martin Thorne, Ph.D.Kale is the hardest of all winter vegetables; properly protected, it will continue to grow at 20 deg. F., and will endure an exposure to frost, which converts its starch into sugar, sweetening and rendering more nutritious its leaves.
Mulching Techniques
- Apply 6-8 inches (15-20 cm) straw before ground freeze
- Use leaf mold for added insulation in windy areas
- Replenish after heavy snow melt
Cover Systems
- Install row covers when temps hit 25°F (-4°C)
- Use hoop houses for extended harvest below 15°F (-9°C)
- Employ cloches for individual plant protection
Plant Preparation
- Water deeply before hard freeze events
- Apply potassium-rich fertilizer six weeks before frost
- Remove damaged leaves to prevent rot
Cold tolerant - mature plants: Mature plants cope with the cold better than young seedlings. Specimens more than 8 weeks old have thicker cell walls, making them more resistant to freezing. In my zone 5 garden, Winterbor kale can be eaten fresh from the plant in January thaws if well-protected when cut from the bed.
Harvesting in winter necessitates some special techniques. Harvest your leaves during the afternoon hours when the temperatures rise above freezing. Gently brush off any accumulated snow before making your cuts. Do not harvest the frozen leaves, as they will become damaged once thawed.
Will kale survive the winter? This wonderfully hardy plant can withstand the cold with the right protection (6-8 inch mulch, row covers, etc.) to an extent, to the tune of 20°F (-7C), especially if the leaves are covered with frost to sweeten them (wait, a plant doing a sugary-leaf act? Starches converted to sugars? Yea!).
Read the full article: How to Grow Kale: Ultimate Guide for Home Gardeners
