Michigan’s cold springs make late May the safest time to transplant collards outdoors. Knowing the best time to plant collard greens in Michigan is key to a big harvest before winter hits. Collards love cool weather but hate frost, so timing matters.
Collards are tough greens that can handle a light freeze. But Michigan’s last frost date can be as late as mid-May in the northern Lower Peninsula. That is why late May is your sweet spot for putting plants in the ground.
This guide covers everything from soil temp to fall planting. You will get a clear timeline and steps that work for your Michigan garden. No fluff, just what you need to know.
Why Timing Matters For Collards In Michigan
Collards grow best when temperatures are between 60°F and 75°F. Michigan’s spring can be chilly, with nights still dropping into the 40s in May. If you plant too early, cold soil stunts growth or kills young plants.
Plant too late, and summer heat makes collards bitter. They bolt (go to seed) fast when temps climb above 80°F. That is why the best time to plant collard greens in Michigan balances cool soil with enough growing days before heat hits.
Michigan has three main growing zones: 4b in the Upper Peninsula, 5a in northern Lower, and 5b-6a in southern areas. Each zone shifts your planting window by a week or two. Southern Michigan near Detroit can plant a bit earlier than the UP.
Understanding Michigan’s Frost Dates
Your last spring frost date is the anchor for planting collards. In southern Michigan (zone 6a), last frost is around April 20 to May 5. In central areas (zone 5b), it is May 5 to May 15. Northern Michigan (zone 4b-5a) waits until May 15 to May 25.
Collard seedlings can survive a light frost (28°F to 32°F) if they are hardened off. But transplants are tender and need protection if temps drop below 25°F. That is why late May is the safest bet statewide.
Check your zip code’s frost date using the Old Farmer’s Almanac online tool. Write it down. Then count backward 4 to 6 weeks for indoor seed starting, or forward 2 weeks after frost for direct sowing.
Best Time To Plant Collard Greens In Michigan
The exact window for transplanting collards outdoors in Michigan is May 20 to June 5. This gives soil time to warm to at least 50°F, which collards need for root growth. Soil colder than 45°F slows them down.
For direct seeding, wait until soil hits 55°F, which is usually late May to early June. Seeds germinate slowly in cold soil and may rot. Use a soil thermometer to check at 2 inches deep.
Fall planting is also possible. For a fall harvest, sow seeds outdoors in late July to mid-August. Collards taste sweeter after a frost, so a fall crop is worth the effort. More on that later.
Spring Planting Timeline For Michigan
Here is a step-by-step timeline that works for most of Michigan. Adjust by 1-2 weeks based on your local frost date.
- Start seeds indoors: 4-6 weeks before last frost. For southern MI, that is March 20 to April 5. For northern MI, April 10 to April 25.
- Harden off seedlings: 7-10 days before transplanting. Set them outside for 1-2 hours on day one, then increase by an hour each day.
- Transplant outdoors: 2 weeks after last frost. For most of MI, that is May 20 to June 5. Space plants 12-18 inches apart.
- Direct sow seeds: Same time as transplanting. Plant seeds 1/4 inch deep, 3 inches apart, then thin to 12 inches.
- Mulch and water: Add 2 inches of straw or shredded leaves after planting. Keep soil moist but not soggy.
If you want a head start, use row covers or cloches in early May. This protects transplants from late frost and warms soil faster. Remove covers when temps stay above 50°F at night.
Fall Planting For Sweet Frost-Kissed Collards
Fall collards are often better than spring ones. Cold weather converts starches to sugars, making leaves sweeter. A light frost improves flavor, not ruins it.
For fall harvest in Michigan, direct sow seeds from July 20 to August 15. This gives collards 60-80 days before hard frosts hit in October. In southern MI, you can push to late August.
Here is a fall planting checklist:
- Choose a spot that gets full sun (6+ hours daily).
- Amend soil with compost or aged manure before planting.
- Sow seeds 1/2 inch deep, 3 inches apart in rows 18 inches apart.
- Thin seedlings to 12 inches apart when they have 4 true leaves.
- Water deeply once a week, more during dry spells.
- Cover with row cloth if temps drop below 20°F in October.
Fall collards can handle temps down to 20°F without damage. If a hard freeze is coming (below 20°F), harvest all leaves and store in the fridge. They keep for weeks.
Soil Preparation For Collards In Michigan
Collards need rich, well-drained soil with a pH between 6.0 and 7.0. Michigan soil is often acidic, especially in the Upper Peninsula. Test your soil pH with a home kit or send a sample to MSU Extension.
If pH is below 6.0, add lime in fall or early spring. Collards need calcium and magnesium, which lime provides. Work 2-3 pounds of lime per 100 square feet into the top 6 inches.
Before planting, mix in 2 inches of compost or well-rotted manure. Collards are heavy feeders and need nitrogen for leaf growth. Avoid fresh manure, which can burn roots.
Here is a quick soil prep routine:
- Clear weeds and rocks from the bed.
- Loosen soil to 8 inches deep with a garden fork.
- Mix in 2 inches of compost and 1 tablespoon of 10-10-10 fertilizer per square foot.
- Rake smooth and water lightly.
If you have clay soil (common in parts of Michigan), add sand or peat moss to improve drainage. Raised beds work great for collards in heavy soil.
Choosing The Right Collard Variety For Michigan
Not all collards handle Michigan’s short summers well. Some varieties bolt fast in heat or take too long to mature. Pick ones that fit your growing window.
Here are top varieties for Michigan:
- Georgia Southern: Heirloom, 60-80 days. Tolerates heat and cold. Good for spring and fall.
- Vates: 60-75 days. Compact, cold-hardy, slow to bolt. Great for northern zones.
- Champion: 60-70 days. Dwarf variety, resists bolting. Perfect for small gardens.
- Flash: 55-65 days. Fast maturing, tender leaves. Ideal for short seasons.
- Morris Heading: 70-80 days. Loose head, sweet after frost. Best for fall.
For the Upper Peninsula, choose Vates or Flash because they mature quickly. Southern Michigan can grow any variety, but Champion and Georgia Southern are reliable.
Buy seeds from local nurseries or online sources like Johnny’s Selected Seeds. Check the days to maturity and compare to your first fall frost date.
Transplanting Collards: Step-By-Step
Transplants give you a head start over seeds. Here is how to do it right in Michigan.
- Harden off plants: Start 7-10 days before transplanting. Place seedlings outside in partial shade for 1 hour on day one. Add 1 hour each day, moving to full sun by day 5.
- Prepare the bed: Water the soil thoroughly the night before. This reduces transplant shock.
- Dig holes: Space holes 12-18 inches apart in rows 18-24 inches apart. Make holes deep enough to cover the root ball.
- Remove seedlings: Gently squeeze the pot to loosen roots. If roots are circling, tease them apart.
- Plant: Set each seedling so the lowest leaves are just above soil level. Fill in with soil and press gently.
- Water: Give each plant 1 cup of water at planting. Use a diluted fish emulsion or seaweed solution for a boost.
- Mulch: Spread 2 inches of straw or shredded leaves around plants. Keep mulch 2 inches away from stems.
- Protect: If temps drop below 50°F at night, cover with row cloth or a cloche for 1-2 weeks.
Transplant on a cloudy day or in late afternoon to reduce stress. Avoid planting in direct midday sun. Water every 2-3 days for the first week until roots establish.
Direct Sowing Collard Seeds In Michigan Soil
Direct sowing is simpler but requires patience. Seeds germinate in 5-10 days if soil is warm enough. Here is the process.
- Wait for soil temp: Use a soil thermometer. Sow when soil is at least 55°F at 2 inches deep.
- Prepare rows: Make shallow furrows 1/4 to 1/2 inch deep. Space rows 18 inches apart.
- Sow seeds: Drop 2-3 seeds every 3 inches along the row. Cover with fine soil and pat down.
- Water gently: Use a mist setting to avoid washing seeds away. Keep soil moist until sprouts appear.
- Thin seedlings: When plants have 4 true leaves, thin to 12 inches apart. Snip extras at soil level, don’t pull.
- Mulch: Add 1 inch of straw after thinning to retain moisture and suppress weeds.
If you sow too early and a cold snap hits, seeds may rot. That is why late May is the best time to plant collard greens in Michigan for direct sowing. In northern zones, early June is safer.
For a continuous harvest, sow a new row every 2 weeks until mid-August. This gives you fresh leaves from June through November.
Caring For Collards Through Michigan’s Seasons
Collards are low-maintenance but need consistent care. Here is what to do each month.
June: Establishment And Growth
- Water deeply once a week if rain is scarce. Collards need 1-1.5 inches of water per week.
- Side-dress with nitrogen fertilizer (like blood meal) 3 weeks after transplanting. Use 1 tablespoon per plant.
- Watch for flea beetles. Use row cover or neem oil if you see tiny holes in leaves.
- Weed regularly. Collards don’t compete well with aggressive weeds.
July: Heat Management
- Mulch heavily to keep soil cool. Add 2 more inches of straw.
- Harvest outer leaves when they are 8-10 inches long. Leave the center to keep growing.
- If temps hit 85°F+, provide afternoon shade with a shade cloth. This prevents bitterness.
- Water in the morning to reduce disease risk.
August: Fall Prep
- Sow fall seeds by mid-August. Water well to help germination in hot soil.
- Remove any bolting plants. They will not produce good leaves.
- Fertilize again with a balanced 10-10-10 fertilizer. Apply 1 tablespoon per plant.
- Check for cabbage worms. Hand pick or use Bt (Bacillus thuringiensis) spray.
September To November: Fall Harvest
- Harvest leaves after a light frost for sweeter flavor. Leave the root in the ground.
- Cover plants with row cloth if temps drop below 20°F. Collards can survive down to 15°F with protection.
- Mulch heavily around roots to insulate from freezing soil.
- Harvest all remaining leaves before a hard freeze (below 20°F). Store in the fridge.
Common Problems Growing Collards In Michigan
Even with good timing, issues can pop up. Here are the most common ones and how to fix them.
Flea Beetles
These tiny black bugs jump when disturbed. They make small holes in leaves, stunting growth. They are worst in warm, dry weather.
Solution: Use floating row cover from planting until plants are 6 inches tall. Diatomaceous earth dust also works. Apply after rain.
Cabbage Worms
Green caterpillars that eat leaves from the underside. They leave large holes and frass (droppings).
Solution: Hand pick every few days. Spray with Bt (a natural bacteria) every 7-10 days. Attract beneficial insects like ladybugs with dill or fennel nearby.
Bolting
When collards send up a flower stalk, leaves turn bitter. This happens in hot weather or if plants are stressed.
Solution: Plant bolt-resistant varieties like Champion or Vates. Keep soil consistently moist. Harvest outer leaves regularly to delay bolting.
Yellow Leaves
Yellowing can mean overwatering, underwatering, or nitrogen deficiency. Check soil moisture first.
Solution: Water only when top 1 inch of soil is dry. Apply a nitrogen-rich fertilizer like fish emulsion if leaves are pale.
Harvesting Collards For Best Flavor
You can start harvesting outer leaves when plants are 8-10 inches tall, usually 60-70 days after planting. Pick the oldest, lowest leaves first. Leave the inner rosette to keep growing.
For spring-planted collards, harvest from June through August. For fall-planted, harvest from September until a hard freeze. Leaves taste best after a light frost.
Here is how to harvest properly:
- Use a sharp knife or scissors to cut leaves at the stem base.
- Never take more than one-third of the leaves at once.
- Harvest in the morning when leaves are crisp.
- Wash leaves in cold water and store in a plastic bag in the fridge. They last 1-2 weeks.
If you want whole heads (for varieties like Morris Heading), wait until the head feels firm. Cut the entire plant at soil level. Use within a few days.
Frequently Asked Questions
Can I Plant Collards In April In Michigan?
Only if you use row covers or a cold frame. Soil is usually too cold in April for direct sowing. Transplants can go out in late April in southern MI with protection, but May is safer.
What Is The Best Time To Plant Collard Greens In Michigan For A Fall Crop?
Late July to mid-August is ideal. This gives collards 60-80 days before hard frosts. In southern MI, you can sow as late as August 20.
How Long Do Collards Take To Grow In Michigan?
Most varieties take 60-80 days from seed to harvest. Transplants cut that to 40-50 days. Fast varieties like Flash mature in 55 days.
Can Collards Survive Michigan Winter?
Collards can survive down to 15°F with heavy mulch and row cover. But Michigan winters below 0°F will kill them. Harvest before hard freeze or grow in a cold frame.
Should I Start Collards Indoors Or Direct Sow In Michigan?
Indoor starts give you a longer growing season and earlier harvest. Direct sowing is easier but requires warm soil. For northern MI, start indoors. For southern MI, either works.
Final Tips For Michigan Collard Growers
Timing is everything, but so is soil prep and variety choice. Stick to the late May transplant window for spring crops. For fall, sow in late July to early August.
Water consistently, mulch well, and watch for pests. Harvest leaves regularly to encourage new growth. And don’t forget to taste test after a frost—the sweetness is worth the wait.
With these steps