How long does kale produce edible leaves?
Written by
Paul Reynolds
Reviewed by
Prof. Martin Thorne, Ph.D.Kale produces edible leaves for 6+ months with good care, but actual time will depend on your climate and harvesting methods. Long-sustained temperatures above 75 °F (24 °C) will cause plants to bolt and decline. Still, I'm able to keep mine productive for 8 months through selective harvesting and sowing a web. A little planning can drastically extend your harvest window.
Harvesting Technique
- Cut-and-come-again: Extends production 2-3 months
- Whole-plant harvest: Ends production immediately
- Frequency: Weekly picking maintains growth
- Tip: Cut ¼ inch above leaf base
Temperature Management
- Ideal range: 40-65°F (4-18°C)
- Decline trigger: 75°F+ (24°C) for 5+ days
- Protection: Shade cloth above 70°F (21°C)
- Effect: Adds 1-2 months in warm zones
Bolting, when the flower stalks are produced, is the final stage. This occurs if the temperature is over 75°F (24°C) for any length of time. I avoid this by planting in semi-shade during the warmer months. Leaves turn bitter 7-10 days after flowering has commenced. Cut remaining leaves before buds form.
Biennial varieties like 'Red Russian' regrow after winter dormancy in zones 7-9. They will resume production in early spring before bolting in summer. I mulch heavily in the fall to protect the crowns of the plants. This second season will allow for 2-3 months of extra harvests from already established plants.
Succession Planting
- Schedule: New plants every 3-4 weeks
- Effect: Continuous 9+ month harvest
- Varieties: Mix early and late bolting types
- Tip: Start seeds indoors during extreme weather
Overwintering Methods
- Protection: Cold frames below 20°F (-7°C)
- Pruning: Cut back to 4 inches before frost
- Regrowth: 4-6 weeks after spring thaw
- Yield: 60% of first season production
Keep watch for tell-tale signs that will determine the lifespan of your kale. If the leaves are becoming pallid, fish emulsion should be given. If these leaves turn yellow, disease is likely present, and the plants should be destroyed; there is no remedy for it. I provide the plants with a new home every year, and, unless you do, your crop won't be a heavy one.
Read the full article: When to Plant Kale: Expert Timing Guide
