Michigan’s lake-moderated climate suits kale planting in early spring and late July for autumn harvests. Knowing the best time to plant kale in Michigan can mean the difference between a bumper crop and a sad, bolted mess. This guide gives you the exact dates and steps for success.
Kale loves cool weather. It actually tastes sweeter after a light frost. Michigan’s unpredictable springs and crisp falls make it a perfect kale-growing state. You just need to time your planting right.
We will cover spring and fall planting windows. You will learn about soil temp, frost dates, and variety selection. Let’s get your kale growing.
Best Time To Plant Kale In Michigan
The absolute best time to plant kale in Michigan is two to three weeks before the last expected spring frost. For most of the Lower Peninsula, that means mid-April. For the Upper Peninsula, aim for early to mid-May.
For a fall harvest, the best time is six to eight weeks before the first expected fall frost. That usually lands in late July or early August. This timing lets kale mature in cool autumn weather.
Spring Planting Windows By Michigan Region
Michigan spans USDA zones 4a to 6b. Your exact window depends on your location. Here are the general guidelines.
- Southern Michigan (Zone 6a/6b): Plant outdoors from March 25 to April 15. Soil temps should be above 40°F.
- Central Michigan (Zone 5b/6a): Plant from April 5 to April 25. Watch for late snow.
- Northern Michigan (Zone 4b/5a): Plant from April 20 to May 10. Use row covers for protection.
- Upper Peninsula (Zone 4a/4b): Plant from May 5 to May 25. Kale grows fast in long summer days here.
Fall Planting Windows For A Sweet Harvest
Fall kale is the best kale. Cold temps convert starches to sugars. You want your plants to mature as days get shorter and cooler.
- Southern Michigan: Direct sow seeds from July 20 to August 10.
- Central Michigan: Direct sow from July 15 to August 5.
- Northern Michigan: Direct sow from July 1 to July 20.
- Upper Peninsula: Direct sow from June 25 to July 15.
If you start seeds indoors for fall, subtract 4 weeks from these dates. Transplant seedlings when they have 4 true leaves.
Understanding Michigan’s Frost Dates
Frost dates are your best friend for kale planting. Kale can handle light frosts down to about 28°F. Hard freezes below 25°F can damage outer leaves.
Average Last Spring Frost Dates
- Detroit/Ann Arbor: April 15-25
- Grand Rapids: April 25 – May 5
- Lansing: April 20-30
- Traverse City: May 5-15
- Marquette: May 20-30
Average First Fall Frost Dates
- Detroit/Ann Arbor: October 15-25
- Grand Rapids: October 5-15
- Lansing: October 5-15
- Traverse City: September 25 – October 5
- Marquette: September 15-25
Kale can survive past the first frost. Many gardeners harvest kale from under snow. The flavor only gets better.
Soil Preparation For Michigan Kale
Kale is not picky, but it rewards good soil. Michigan soil varies from sandy loam to heavy clay. You need to adjust your approach.
Testing Your Soil PH
Kale likes a pH between 6.0 and 7.5. Michigan’s acidic soil often needs lime. Test your soil in fall or early spring.
Add garden lime if your pH is below 6.0. Work it into the top 6 inches of soil. Do this at least 2 weeks before planting.
Amending Heavy Clay Soil
Clay soil holds water and can rot kale roots. Mix in 2-3 inches of compost or aged manure. Add coarse sand if drainage is very poor.
Raised beds work great for clay soil. They warm up faster in spring too. This helps you plant earlier.
Fertilizing For Strong Growth
Kale is a heavy feeder. Before planting, mix in a balanced 10-10-10 fertilizer. Use about 1 pound per 100 square feet.
Side-dress with nitrogen-rich fertilizer when plants are 6 inches tall. Fish emulsion or blood meal work well. Apply every 3-4 weeks during the growing season.
Choosing The Right Kale Varieties For Michigan
Not all kale is created equal. Some varieties handle Michigan’s swings better than others. Here are top picks.
Cold-Hardy Varieties For Early Spring
- Winterbor: Very cold tolerant. Grows well in spring and fall.
- Red Russian: Tender leaves. Survives down to 10°F.
- Siberian: Extremely hardy. Good for northern Michigan.
Heat-Tolerant Varieties For Late Summer
- Lacinato (Dinosaur): Holds up in heat. Good for fall planting.
- Scarlet: Ornamental and edible. Tolerates summer heat.
- Starbor: Hybrid that resists bolting. Great for July sowing.
Fast-Maturing Varieties
If you are late planting, choose quick varieties. They mature in 50-55 days.
- Dwarf Blue Curled: Ready in 55 days. Compact plant.
- Premier: Ready in 50 days. Very tender.
- Vates: Ready in 55 days. Good for containers.
Step-By-Step Planting Guide
Follow these steps for a successful kale crop. Whether you start seeds indoors or direct sow, the process is simple.
Starting Seeds Indoors
- Fill seed trays with seed-starting mix. Moisten the mix.
- Sow seeds 1/4 inch deep. Cover lightly with mix.
- Place trays under grow lights or in a sunny window. Keep soil at 65-70°F.
- Seeds germinate in 5-8 days. Thin to one seedling per cell.
- Harden off seedlings for 7-10 days before transplanting. Set them outside for a few hours each day, increasing time.
- Transplant when seedlings have 4-5 true leaves. Space them 12-18 inches apart.
Direct Sowing Outdoors
- Prepare the bed. Remove weeds and rake smooth.
- Sow seeds 1/2 inch deep. Space seeds 2 inches apart in rows.
- Cover seeds with soil and water gently. Keep soil moist.
- Thin seedlings to 12 inches apart when they have 2-3 true leaves.
- Use row covers if frost is forecast. Remove covers when temps rise above 80°F.
Transplanting Seedlings
- Dig holes 12-18 inches apart. Make holes deep enough for the root ball.
- Place seedling in hole. Fill with soil and firm gently.
- Water thoroughly. Add a layer of mulch to retain moisture.
- Protect from wind with cloches or row covers for the first week.
Caring For Your Kale Plants
Kale is low maintenance, but a little care goes a long way. Focus on water, pests, and harvesting.
Watering Requirements
Kale needs consistent moisture. Give it 1-1.5 inches of water per week. Water at the base to avoid leaf diseases.
In sandy Michigan soil, water more often. In clay soil, water less. Check soil moisture 2 inches down. If dry, water.
Pest Management
Michigan has cabbage worms, aphids, and flea beetles. These pests love kale.
- Cabbage worms: Hand pick them. Use Bt (Bacillus thuringiensis) spray for large infestations.
- Aphids: Blast off with water. Use insecticidal soap if needed.
- Flea beetles: Use row covers on young plants. Apply diatomaceous earth.
Companion planting helps. Plant kale near onions, garlic, or dill. These repel pests.
Mulching And Weed Control
Mulch keeps soil cool and moist. Use straw, shredded leaves, or grass clippings. Apply 2-3 inches around plants.
Weeds compete for nutrients. Pull them by hand or use a hoe. Be careful not to disturb kale roots.
Harvesting Kale At The Right Time
You can start harvesting baby kale leaves in 30 days. Full-sized leaves are ready in 50-75 days.
How To Harvest
- Pick outer leaves first. Leave the inner rosette to grow.
- Cut leaves at the stem. Use scissors or a sharp knife.
- Harvest from the bottom up. Do not take more than 1/3 of the plant at once.
- Continue harvesting until hard frost. Kale can survive into December.
Harvesting After Frost
Frost improves kale flavor. Wait for a light frost before your main harvest. Leaves will be sweeter and less bitter.
If a hard freeze is coming, harvest all remaining leaves. Store them in a plastic bag in the fridge. They last 1-2 weeks.
Common Michigan Kale Growing Mistakes
Even experienced gardeners make errors. Here are the most common ones and how to avoid them.
Planting Too Late In Spring
Kale bolts when temps hit 80°F. If you plant in May in southern Michigan, your kale may flower early. Plant in March or April instead.
Planting Too Early In Fall
Fall kale needs cool weather to mature. If you plant in August, it may get too hot. Wait until late July or early August.
Overcrowding Plants
Kale needs space. Crowded plants get powdery mildew and grow small leaves. Thin seedlings to 12 inches apart.
Ignoring Soil PH
Michigan soil is often acidic. Kale needs neutral pH. Test and amend your soil. Yellow leaves often mean low pH.
Extending The Growing Season
You can grow kale almost year-round in Michigan. Use season extension techniques.
Using Row Covers
Floating row covers protect from frost and pests. They add 2-4 weeks to your season. Use them in early spring and late fall.
Cold Frames And Hoop Houses
Cold frames let you plant 3-4 weeks earlier. Hoop houses keep kale alive all winter. Build a simple hoop house with PVC pipes and plastic.
Winter Mulching
Cover kale with 12 inches of straw before hard freeze. The plants will stay dormant. Remove mulch in early spring for a head start.
Frequently Asked Questions
Can I plant kale in Michigan in June?
It is not ideal. June planting often leads to bolting. If you must, choose a heat-tolerant variety and provide shade. Harvest baby leaves quickly.
What is the latest I can plant kale in Michigan?
For fall harvest, plant by mid-August in southern Michigan. For winter harvest, plant in a cold frame by early September.
Should I soak kale seeds before planting?
No. Kale seeds germinate easily without soaking. Soaking can cause rot. Just plant them in moist soil.
How deep do I plant kale seeds?
Plant seeds 1/4 to 1/2 inch deep. Cover lightly with soil. Deeper planting reduces germination.
Can kale survive Michigan winter?
Yes, with protection. Kale can survive down to 10°F under row covers or snow. In severe cold, use a cold frame.
Final Tips For Michigan Kale Growers
Kale is one of the easiest crops for Michigan gardens. The key is timing. Plant early for spring, and plant in late summer for fall.
Watch your local weather. Use frost dates as a guide, but adjust for microclimates. A south-facing slope warms up faster.
Do not be afraid to experiment. Try different varieties and planting dates. You will find what works for your garden.
Kale is forgiving. Even if you plant a bit late, you will get a harvest. The leaves might be smaller, but they will still taste great.
Michigan’s climate is perfect for kale. With the right timing, you can enjoy fresh kale from April to December. Start planning your planting dates now.
Remember, the best time to plant kale in Michigan is early spring for summer harvest and late July for autumn harvest. Stick to these windows, and you will have a bountiful crop.
Happy growing, Michigan gardener. Your kale patch awaits.