When To Plant Radishes In Michigan

If you’re wondering when to plant radishes in Michigan, you’re in the right place. Timing is the most important factor for a crunchy, successful harvest, and getting it right depends on whether you’re sowing in spring or fall.

Michigan’s climate, with its distinct seasons and sometimes unpredictable frost dates, offers two excellent planting windows. This guide gives you the simple, practical steps to hit those windows perfectly.

For a spring crop, you can start planting radish seeds as soon as the garden soil can be worked. This is typically 4-6 weeks before the last average spring frost date. For a fall crop, aim to plant seeds about 4-6 weeks before the first average fall frost.

Radishes are a cool-season crop. They thrive in the milder temperatures of spring and fall and can struggle in Michigan’s summer heat.

Understanding Your Michigan Frost Dates

Your local frost dates are your best guide. Michigan spans USDA Hardiness Zones 4 to 6, so dates vary.

Southern Michigan (Zone 6): Last spring frost around May 1. First fall frost around October 15.
Central/Northern Michigan (Zones 4-5): Last spring frost from mid-May to early June. First fall frost from late September to early October.

Always check a local extension service for the most accurate dates for your exact town. Planting to early in cold, wet soil can cause seeds to rot.

Spring Planting Schedule

The goal is to get radishes grown and harvested before summer heat arrives, which can make them woody and spicy.

First Planting: As early as mid-March in southern areas, early April further north, as soon as soil is no longer soggy.
Succession Planting: Sow a new small row every 7-10 days until late April. This staggers your harvest.
Final Spring Planting: Your last spring sowing should be done by early to mid-May at the latest.

Fall Planting Schedule

Fall is often the best time for radishes in Michigan. Cooler temperatures and fewer pests lead to sweeter, more tender roots.

Main Planting Window: Start sowing seeds again in mid-to-late August.
Continue Planting: You can make successive plantings through September.
Late Fall Harvest: For a late harvest, plant quick-maturing varieties by the first week of October. They will mature in the cool autumn soil.

Choosing the Right Radish Variety

Match your variety to the season for best results.

Best for Spring & Fast Harvests:

Cherry Belle: Classic round, red radish. Ready in 22 days.
French Breakfast: Oblong, mild flavor. Ready in 24 days.
Easter Egg Blend: A mix of colorful round radishes.

Best for Fall & Winter Storage:

Daikon: Large, long white radish. Takes 50-60 days, perfect for fall’s longer cool period.
Watermelon: Beautiful green skin with a pink interior. Sweet and crisp.
Black Spanish: Hardy, stores extremely well in root cellars.

Step-by-Step Planting Guide

Follow these simple steps for a great crop.

Prepare the Soil: Choose a sunny spot. Radishes need loose, well-draining soil. Remove stones and break up clumps to a depth of at least 6 inches. Mix in some compost, but avoid high-nitrogen fertilizers which promote leafy tops over roots.
Sow the Seeds: Plant seeds 1/2 inch deep. Space them about 1 inch apart in rows that are 6-12 inches apart. You can also broadcast seeds in a wide row.
Water Gently: Keep the seed bed consistently moist until seedlings emerge in 4-7 days. Don’t let it dry out.
Thin Seedlings: Once they have their first true leaves, thin seedlings to 2-3 inches apart. Crowded radishes won’t form bulbs properly. The thinnings are edible in salads!
Ongoing Care: Water evenly, about 1 inch per week. Uneven watering causes splitting. A light mulch can help retain moisture and suppress weeds.

Common Problems and Solutions

Even easy crops have issues. Here’s how to fix them.

All Leaf, No Bulb: Usually means too much shade, overcrowding, or too much nitrogen fertilizer. Thin properly and ensure full sun.
Woody or Extremely Spicy Roots: Caused by hot weather or letting them grow to old. Harvest on time and stick to spring/fall windows.
Root Maggots: A common pest. Use floating row covers to prevent the fly from laying eggs at the base of plants.
Flea Beetles: They create tiny holes in leaves. Row covers are the best organic defense.

Harvesting and Storing Your Radishes

Harvesting at the right time is key to flavor.

When to Harvest: Check your seed packet for “days to maturity.” Most spring radishes are ready in 22-30 days. Gently brush away soil at the top of the root to check its size.
How to Harvest: Simply pull them up by the greens. If soil is hard, loosen it first with a fork. Don’t leave them in the ground to long after maturity.
Storage: For immediate use, remove greens (they draw moisture from the root), wash, and refrigerate in a bag for 1-2 weeks. For winter storage radishes like Daikon, they can be kept in a cool, humid place like a root cellar for months.

FAQ: Planting Radishes in Michigan

Can I plant radishes in the summer in Michigan?
It’s not recommended. Summer heat causes poor bulb formation and excessive pungency. Focus on spring and fall.

How early can I plant radish seeds in spring?
As soon as the soil is workable—not frozen or waterlogged. Radish seeds can germinate in soil temperatures as low as 40°F.

What if my spring got away from me and I forgot to plant?
No problem! The fall planting season is often even better. Just mark your calendar for a mid-August sowing.

Can I grow radishes in containers?
Absolutely. Choose a pot at least 6 inches deep. Ensure it has drainage holes and keep the soil moist. This is a great option for small spaces.

Why did my radishes split?
Splitting is usually caused by irregular watering, especially a heavy rain after a dry period. Try to maintain even soil moisture.

By following these simple timing guidelines and care tips, you can enjoy a steady supply of crisp, homegrown radishes from your Michigan garden for much of the year. The key is to respect the cool seasons they love.