Planting Guides

When to Plant Kale in Minneapolis: Complete Guide + Best Varieties for Zone 4a

Minneapolis, Minnesota

USDA Zone 4a

Last Frost: May 15

Last updated: October 30, 2025

Learn when to plant kale in Minneapolis with specific dates for Zone 4a. Compare 5 varieties, get a complete timeline, and discover which kale grow best in Minnesota's climate.

DDorothy "Dot" Williams

October 30, 2025

Kale plants thriving in Minneapolis Zone 4a garden with frost-sweetened leaves ready for harvest — — Image © PlantReference.org 2025

Quick Answer

Plant kale in Minneapolis July 15-August 15 for fall harvest or April 1-15 for spring crop. Fall plantings produce sweeter, more tender leaves after frost exposure.

TL;DR

Plant kale in Minneapolis between July 15-August 15 for fall harvest and April 1-15 for spring crop. Brassica oleracea 'Winterbor' excels in Zone 4a with extreme cold tolerance to -10°F. Fall-planted kale tastes significantly sweeter after Minneapolis frosts improve flavor through natural sugar conversion.

Product Recommendations

Winterbor Kale Seeds

($4-6)— Extreme cold tolerance perfect for Minneapolis winters

Winterbor F1 Hybrid Kale Seeds - 200 Seeds

https://www.johnnyseeds.com/vegetables/greens/kale/winterbor-f1-kale-seed-556.html

Winterbor delivers exceptional cold hardiness for Minneapolis Zone 4a conditions, surviving temperatures to -10°F with mulch protection. Deep blue-green curled leaves develop incredible sweetness after frost exposure. This F1 hybrid produces uniform plants with vigorous growth and excellent overwintering ability. Highly productive with continuous harvest potential from September through March with protection. Resistant to common brassica diseases and ideal for succession planting in Minneapolis climate.

Price: $4.95-$6.50

Lacinato Kale Seeds

($3-5)— Premium eating quality with good Minneapolis cold tolerance

Lacinato (Dinosaur) Kale Heirloom Seeds - 500 Seeds

https://www.southernexposure.com/products/lacinato-kale/

Lacinato kale offers the finest eating quality for Minneapolis gardens with distinctive flat, savoyed leaves that concentrate flavor beautifully in cold weather. Also called Tuscan or Dinosaur kale, this Italian heirloom develops nutty, sweet flavor after Minneapolis frost exposure. Excellent fresh or cooked, with tender texture requiring no massaging for raw use. Cold hardy to 15°F and produces continuously when harvested properly. Dark blue-green leaves add visual interest to winter Minneapolis gardens.

Price: $3.25-$4.95

Floating Row Cover

($18-25)— Essential protection for Minneapolis season extension

Agribon AG-15 Floating Row Cover - 10ft x 25ft

https://www.planetnatural.com/product/agribon-row-cover/

This lightweight 0.55oz spun fabric provides 3-5°F frost protection while allowing light, air, and water penetration. Perfect for extending Minneapolis kale harvest through November and December. Excludes cabbage white butterflies and other pests without pesticides. UV-stabilized for multi-season use and won't tear in Minneapolis winds. Easy to install over hoops or directly over plants. Helps kale establish faster in cool spring conditions and protects against unexpected early frosts.

Price: $18.50-$24.95

Bt Organic Caterpillar Spray

($12-16)— Safe, effective cabbage worm control

Safer Brand Caterpillar Killer Bt Concentrate - 16oz

https://www.saferbrand.com/safer-brand-caterpillar-killer-concentrate-16-oz-5163

Contains Bacillus thuringiensis kurstaki strain for organic control of cabbage worms, loopers, and hornworms on Minneapolis kale. This naturally occurring soil bacterium specifically targets caterpillars while being completely safe for humans, pets, and beneficial insects. Concentrate formula covers large areas economically - one bottle treats entire season's kale crop. Apply weekly during peak cabbage worm season (July-September in Minneapolis). OMRI-listed for certified organic production and perfect for chemical-free gardens.

Price: $11.95-$15.50

Cold Frame Kit

($89-120)— Extend Minneapolis kale harvest through winter

Palram Mythos Cold Frame Greenhouse - 3x2 feet

https://www.greenhousemegastore.com/product/palram-mythos-cold-frame/

This aluminum and polycarbonate cold frame creates a protected microclimate for Minneapolis winter kale production. Twin-wall polycarbonate panels provide excellent insulation while allowing maximum light. Automatic hydraulic opener prevents overheating on warm winter days. Rust-resistant aluminum frame withstands Minneapolis weather extremes. Perfect size for 4-6 mature kale plants and extends harvest through January and February. Easy assembly with pre-cut panels and detailed instructions included.

Price: $89.00-$119.95

Frequently Asked Questions

When is the best time to plant kale in Minneapolis?

The ideal time to plant kale in Minneapolis is July 15 through August 15 for fall harvest. This timing allows plants to mature in cool weather and develop peak sweetness after frost exposure. Spring planting from April 1-15 also works well but produces less flavorful results since plants mature in warming weather rather than cooling conditions.

Can kale survive Minneapolis winters?

Yes, certain kale varieties survive Minneapolis winters with protection. Brassica oleracea 'Winterbor' tolerates temperatures down to -10°F (-23°C) when heavily mulched with straw. Most varieties need protection below 15°F (-9°C). Use cold frames, heavy mulch, or row covers to extend harvest through December and January. Snow cover actually insulates plants and improves survival rates.

What kale varieties grow best in Zone 4a Minneapolis climate?

Brassica oleracea 'Winterbor' performs best in Minneapolis for cold tolerance and overwintering ability. Brassica oleracea 'Lacinato' offers superior eating quality with good cold hardiness. Brassica oleracea 'Red Russian' works excellently for quick spring crops, maturing in 50-60 days. All varieties benefit from Minneapolis's cool fall temperatures that sweeten leaves naturally through frost exposure.

How long does it take kale to grow in Minneapolis?

Kale typically matures in 50-75 days in Minneapolis, depending on variety. Brassica oleracea 'Red Russian' matures fastest at 50-60 days, while Brassica oleracea 'Winterbor' and Brassica oleracea 'Lacinato' need 60-75 days. However, you can begin harvesting young leaves at 30-40 days. Minneapolis's 138-day growing season from May 14 to September 29 easily accommodates multiple plantings and succession crops.

Should I start kale seeds indoors or direct sow in Minneapolis?

Both methods work well in Minneapolis. Direct sowing works better for fall crops (July-August plantings) since soil temperatures are warm and weather is stable. Indoor starting works better for spring crops to avoid soil that's too cold and wet in April. Start spring seeds indoors 6-8 weeks before last frost (March 15-30), then transplant outdoors April 20-May 1.

Why does my Minneapolis kale taste bitter and how do I fix it?

Bitter kale usually results from heat stress or harvesting too young. In Minneapolis, spring-planted kale often turns bitter when summer temperatures exceed 80°F (27°C), causing the plant to produce defensive compounds. The solution is fall planting - kale planted in July-August develops sweetness as cool weather arrives. Frost exposure actually converts starches to sugars, making fall-harvested Minneapolis kale significantly sweeter than spring crops.

What pests attack kale in Minneapolis and how do I control them?

Cabbage worms are the primary pest, peaking June-August. Control with Bt spray or row covers. Aphids cluster on undersides of leaves in May-June and September-October - use strong water sprays or insecticidal soap. Flea beetles create shot-holes in young spring plants - protect with row covers for first 4-6 weeks. Fall plantings experience less pest pressure than spring crops, another advantage of late-season planting in Minneapolis.

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Written By

Dorothy "Dot" Williams

Dot grew up on a small farm in rural Virginia and has maintained a vegetable garden for decades. After retiring from teaching elementary school, she became a Master Gardener volunteer and spends her time mentoring new gardeners at community garden plots in Richmond. She's especially knowledgeable about heirloom varieties, seed saving, and traditional growing methods passed down from her grandmother. Dot's no-nonsense advice comes from extensive trial and error—she's seen every tomato disease, pest problem, and weather disaster imaginable. Her biggest pet peeve is gardeners who overcomplicate simple tasks. "Plants want to grow," she often says. "Your job is to not get in their way."