Planting Guides
When to Plant Kale in Indianapolis: Complete Guide + Best Varieties for Zone 5b
Indianapolis, Indiana
USDA Zone 5b
Last Frost: May 5
Last updated: October 30, 2025
Plant kale in Indianapolis July 20-August 10 for fall harvest or March 15-April 1 for spring. Zone 5b's 158-day season is perfect for sweet, frost-kissed kale.
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Quick Answer
Plant kale in Indianapolis July 20-August 10 for fall harvest or March 15-April 1 for spring. Fall-planted kale tastes sweeter after October's first frost.
TL;DR
Plant kale in Indianapolis July 20-August 10 for superior fall harvest or March 15-April 1 for spring crop. Zone 5b's first frost on October 9 sweetens kale leaves naturally. Brassica oleracea 'Winterbor' and Brassica oleracea 'Vates' handle Indianapolis winters best with protection, while Brassica oleracea 'Red Russian' matures fastest for spring plantings.
Frequently Asked Questions
When is the best time to plant kale in Indianapolis?
The best time to plant kale in Indianapolis is July 20 through August 10 for fall harvest. This timing allows plants to mature before the October 9 first frost and develop the sweetest flavor. Spring planting from March 15 through April 1 also works but produces inferior flavor compared to fall crops. Fall-planted kale benefits from Indianapolis's natural cooling cycle and first frost, which converts starches to sugars for dramatically improved taste.
What kale varieties grow best in Indianapolis Zone 5b?
Brassica oleracea 'Winterbor' is the top choice for Indianapolis gardeners because it survives our Zone 5b winters with protection and develops exceptional sweetness after frost. Brassica oleracea 'Red Russian' works excellently for spring planting due to its 50-60 day maturity, allowing harvest before summer heat. Brassica oleracea 'Lacinato' handles Indianapolis's variable spring weather well, while Brassica oleracea 'Redbor' provides beautiful purple color that intensifies in cold weather. Brassica oleracea 'Vates' works well for small Indianapolis urban gardens due to its compact size.
Can kale survive Indianapolis winters?
Yes, kale can survive Indianapolis winters with proper protection. Brassica oleracea 'Winterbor' and Brassica oleracea 'Redbor' are the most cold-hardy varieties for Indianapolis Zone 5b conditions. Provide protection using row covers, cold frames, or heavy mulching when temperatures drop below 20°F. Plants may go dormant during the coldest periods (December-February) but resume growth in March. Harvest is possible throughout mild winter periods and provides the sweetest kale of the year.
Why does my spring-planted kale turn bitter in Indianapolis?
Spring-planted kale turns bitter in Indianapolis because our rapid transition from cool spring to hot summer triggers bolting (flowering). When daytime temperatures consistently exceed 80°F in late May and June, kale plants shift energy from leaf production to reproduction, causing leaves to become tough and bitter. This is why fall planting is superior in Indianapolis—the gradual cooling prevents bolting and actually improves flavor. For spring success, plant Brassica oleracea 'Red Russian' which matures in 50-60 days before heat arrives.
How do I protect young kale seedlings from Indianapolis summer heat?
Protect young kale seedlings planted in July-August from Indianapolis summer heat by providing afternoon shade using shade cloth (30-50% shade), planting in locations that receive morning sun but afternoon shade, ensuring consistent soil moisture but not waterlogged conditions, and using mulch around plants to keep soil cool. During extreme heat waves above 90°F, provide temporary shade using lightweight fabric or umbrellas. Plant during cooler weather periods when possible and avoid planting during heat advisories.
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Written By
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Priya Sharma
Priya is a soil scientist at an agricultural extension office who gardens on a quarter-acre suburban lot in Indianapolis. Her professional work focuses on soil health and nutrient management, which gives her a perspective most gardening writers don't have—she thinks about what's happening underground before worrying about what's happening above it. Priya maintains a large pollinator garden, grows herbs and vegetables, and is slowly converting her conventional lawn to a mix of native grasses and low-growing groundcovers. She writes about soil health, composting, fertilizer use, and building the kind of foundation that makes plants thrive without constant intervention.
