Minnesota gardeners in September race against the clock with fast-maturing vegetables that can handle sudden cold snaps. Finding the best vegetables to plant in september in minnesota means choosing crops that thrive in cooler temps and shorter days. You can still harvest a rewarding fall crop if you pick the right varieties and plant them early enough.
September in Minnesota brings crisp mornings and the first hints of frost. Your window for planting is tight, but it’s wide enough for several hardy vegetables. These plants grow quickly and tolerate light freezes, giving you fresh produce well into October.
This guide covers the top choices for late-season planting. You’ll learn what to sow, when to plant, and how to protect your garden from early frost. Let’s get started with the best options for your Minnesota garden.
Best Vegetables To Plant In September In Minnesota
These vegetables are your best bet for a successful September planting. They mature fast, handle cold soil, and can survive a light frost. Each one has specific needs, but all are beginner-friendly.
Leafy Greens For Quick Harvests
Leafy greens are the stars of fall gardening. They grow rapidly and you can harvest them as baby greens in just a few weeks. Spinach, kale, and arugula are top picks for Minnesota.
Spinach is extemely cold-hardy. It can survive temperatures down to 20°F once established. Plant seeds 1/2 inch deep in well-drained soil. Space them 2 inches apart for full-sized leaves or closer for baby greens.
Kale gets sweeter after a frost. The cold converts starches to sugars, giving it a milder flavor. Sow seeds 1/2 inch deep and thin seedlings to 12 inches apart. Kale takes about 50 days to mature, so plant by early September.
Arugula grows even faster than spinach. You can harvest leaves in 20 to 30 days. It prefers cool weather and bolts quickly in heat. Plant seeds 1/4 inch deep and keep the soil moist.
- Spinach: Matures in 30-45 days, handles frost well
- Kale: Sweeter after frost, 50-60 days to maturity
- Arugula: Ready in 20-30 days, best for quick harvests
- Lettuce: Loose-leaf types mature in 30-40 days
- Swiss chard: Colorful and hardy, 50-60 days
Root Vegetables For Fall Storage
Root crops are perfect for September planting. They store well and taste better after cool weather. Carrots, beets, and radishes are reliable choices.
Carrots need loose, sandy soil to grow straight. Plant seeds 1/4 inch deep and keep the soil moist until germination. Thin seedlings to 2 inches apart. Carrots can stay in the ground after frost and actually sweeten in cold soil.
Beets are dual-purpose plants. You can eat the roots and the greens. Soak seeds overnight before planting to speed germination. Plant 1/2 inch deep and thin to 3 inches apart. Beets mature in 50 to 60 days.
Radishes are the fastest root crop. Some varieties are ready in just 25 days. Plant seeds 1/2 inch deep and thin to 1 inch apart. Radishes are great for marking rows of slower-growing vegetables.
- Prepare soil by removing rocks and breaking up clumps
- Sow seeds at the proper depth for each crop
- Water gently but thoroughly after planting
- Thin seedlings to give roots room to grow
- Mulch around plants to retain moisture and regulate soil temp
Brassicas For Cold Tolerance
The cabbage family thrives in cool weather. Broccoli, cauliflower, and Brussels sprouts can handle Minnesota falls. Start these from transplants for best results.
Broccoli grows well in September if you use transplants. Set plants 18 inches apart in rich soil. Harvest the main head before it flowers, then side shoots will keep producing. Broccoli can survive light frosts.
Cauliflower is more sensitive than broccoli. It needs consistent moisture and cool temps to form heads. Blanch the heads by tying leaves over them when they reach 2 inches wide. This keeps them white and tender.
Brussels sprouts take longer to mature but are worth the wait. They need 80 to 100 days from transplant. Plant them in early September for a late October harvest. Frost improves their flavor.
Tips For Brassicas
Use row covers to protect against cabbage worms. These pests are active in early fall. Check leaves weekly and remove any caterpillars you find.
Fertilize with a balanced vegetable fertilizer at planting time. Brassicas are heavy feeders. Side-dress with compost mid-season for extra nutrients.
Planting Techniques For September Success
Your planting method matters as much as what you plant. September soil is warm, which helps seeds germinate fast. But the decreasing daylight means you need to maximize every growing day.
Direct Seeding Vs Transplants
Some vegetables do better from transplants in September. Others grow fine from seed. Knowing which to use saves time and increases success.
Transplants work best for slower-growing crops like broccoli and cauliflower. They give you a 4-6 week head start. Buy healthy plants from a garden center or start your own in August.
Direct seeding is fine for fast-growing crops. Radishes, spinach, and arugula germinate quickly in warm soil. Plant seeds 1/4 to 1/2 inch deep and water well.
- Use transplants for: broccoli, cauliflower, kale, Brussels sprouts
- Direct seed: radishes, spinach, arugula, lettuce, carrots, beets
- Both methods work: Swiss chard, turnips, mustard greens
Soil Preparation For Fall Gardens
Good soil is key for fall vegetables. Remove spent summer plants and weeds. Add 2 inches of compost and work it into the top 6 inches of soil.
Test your soil pH if you haven’t recently. Most vegetables prefer a pH between 6.0 and 7.0. Add lime if needed to raise pH, or sulfur to lower it.
Warm the soil with black plastic if you plant in late September. This helps seeds germinate faster. Remove the plastic after seedlings appear.
Watering And Mulching
September can be dry in Minnesota. Water new seeds daily until they germinate. After that, water deeply once a week if rain is scarce.
Mulch around plants with straw or shredded leaves. This keeps soil temperature stable and retains moisture. Mulch also prevents weeds from competing with your vegetables.
Reduce watering as temperatures drop. Overwatering in cool weather can cause root rot. Let the soil dry slightly between waterings.
Frost Protection Strategies
Frost is the biggest risk for September plantings. Minnesota can see frost as early as mid-September in northern areas. Southern Minnesota usually gets frost in early October.
Row Covers And Cloches
Row covers are lightweight fabric that protects plants from frost. They let light and water through while trapping heat. Use them on nights when frost is predicted.
Cloches are individual plant covers. You can use plastic bottles, glass jars, or commercial products. Remove them during the day to prevent overheating.
Floating row covers are the easiest option. Drape them over hoops or directly on plants. Secure the edges with soil or rocks.
Cold Frames And Hoop Houses
Cold frames extend your season by several weeks. They are simple boxes with glass or plastic tops. Place them over your garden beds to create a mini greenhouse.
Hoop houses are larger structures made from PVC pipes and plastic. They can cover entire rows of vegetables. Hoop houses are cheap and easy to build.
Both options let you grow vegetables into November. They also protect plants from wind and heavy rain.
When To Cover Plants
Cover plants before sunset on cold nights. This traps daytime heat inside. Remove covers in the morning when temperatures rise above freezing.
Watch the weather forecast closely. A light frost of 28-32°F won’t kill most cold-hardy vegetables. A hard frost below 28°F requires protection.
Specific Varieties For Minnesota Falls
Not all vegetable varieties perform well in September. Choose ones bred for cold tolerance and short seasons. These varieties are proven winners for Minnesota.
Spinach Varieties
‘Bloomsdale’ is a classic spinach for fall. It has thick, crinkly leaves and handles cold well. ‘Space’ is another good choice with smooth leaves and fast growth.
‘Winter Bloomsdale’ is extemely hardy. It can survive winter with protection. Plant it in early September for late fall harvests.
Carrot Varieties
‘Nantes’ carrots are sweet and crisp. They mature in 60 days and store well. ‘Danvers’ is another reliable type with good flavor.
‘Little Finger’ is a baby carrot that matures in 50 days. It’s perfect for quick harvests. Plant them in September for October eating.
Kale Varieties
‘Lacinato’ kale, also called dinosaur kale, has dark blue-green leaves. It’s very cold hardy and tastes great after frost. ‘Red Russian’ kale has purple stems and a mild flavor.
‘Winterbor’ is a curly kale that stands up to snow. It keeps producing even after hard freezes. Plant it in September for winter harvests under cover.
- Spinach: Bloomsdale, Space, Winter Bloomsdale
- Carrots: Nantes, Danvers, Little Finger
- Kale: Lacinato, Red Russian, Winterbor
- Radishes: Cherry Belle, French Breakfast, White Icicle
- Beets: Detroit Dark Red, Golden, Chioggia
Timing Your September Planting
When exactly should you plant in September? The answer depends on your location in Minnesota and the crop you choose. Use these guidelines to plan your planting schedule.
Northern Minnesota
Northern Minnesota has a shorter growing season. First frost often comes in mid-September. Plant fast-maturing crops by September 1 at the latest.
Radishes and arugula are your best bets. They can be ready in 25-30 days. Spinach and lettuce also work if you use transplants or cold frames.
Avoid planting Brussels sprouts or other long-season crops. They won’t have time to mature before winter.
Central Minnesota
Central Minnesota has a slightly longer window. First frost usually arrives in late September or early October. You can plant until September 10 for most crops.
Kale, spinach, and carrots are good choices. Use row covers to protect against early frost. You can harvest into October with proper care.
Broccoli and cauliflower transplants can go in by September 5. They need about 60 days to mature.
Southern Minnesota
Southern Minnesota has the longest fall season. First frost typically comes in early to mid-October. You can plant until September 15 for many crops.
Beets, turnips, and Swiss chard do well here. You can also plant peas for a fall harvest. Peas need cool weather and mature in 60 days.
Use cold frames to extend your season into November. Southern Minnesota gardeners often harvest fresh greens for Thanksgiving.
Companion Planting For Fall Gardens
Companion planting helps your September vegetables grow better. Some plants repel pests, while others improve soil or provide shade.
Good Companions
Plant onions or garlic near carrots. Their smell deters carrot flies. Marigolds also repel many garden pests with their strong scent.
Grow lettuce under taller plants like broccoli. Lettuce benefits from partial shade as temperatures cool. Broccoli benefits from the moisture lettuce helps retain.
Plant beans near beets. Beans fix nitrogen in the soil, which beets need. This natural partnership improves both crops.
Plants To Avoid
Don’t plant onions near beans or peas. Onions can stunt their growth. Keep brassicas away from strawberries, which can harbor diseases.
Avoid planting the same crop family in the same spot two years in a row. Rotate your garden beds to prevent soil-borne diseases.
Harvesting Your Fall Vegetables
Harvesting at the right time ensures the best flavor and texture. Fall vegetables often taste better after a light frost. But don’t wait too long or they may become tough.
When To Harvest
Harvest leafy greens when they reach 4-6 inches tall. Pick outer leaves first and let the inner leaves continue growing. This gives you multiple harvests from one plant.
Pull root vegetables when they reach the right size. Carrots should be 1/2 to 1 inch thick. Beets are best at 1-2 inches in diameter. Radishes get woody if left too long.
Harvest broccoli heads when they are tight and dark green. Cut the main head with 6 inches of stem. Side shoots will produce smaller heads later.
Storing Fall Vegetables
Most fall vegetables store well in a cool, dark place. Carrots and beets keep for months in a root cellar or refrigerator. Remove the greens before storing to prevent moisture loss.
Leafy greens are best eaten fresh. They can last a week in the refrigerator if wrapped in damp paper towels. Use them quickly for the best flavor.
Kale and Brussels sprouts actually improve after frost. You can leave them in the garden under snow and harvest as needed. They stay fresh and sweet all winter.
Common Mistakes To Avoid
Even experienced gardeners make mistakes with fall planting. Here are the most common ones and how to avoid them.
Planting Too Late
The biggest mistake is planting too late in September. Check your first frost date and count backward from there. Add 10-14 days for germination and growth slowdown in cool weather.
If you’re unsure, plant earlier rather than later. You can always harvest immature vegetables like baby greens. But you can’t speed up time once frost hits.
Ignoring Soil Temperature
Soil temperature affects germination. Most seeds need soil above 50°F to sprout. Use a soil thermometer to check before planting.
If soil is too cold, warm it with black plastic for a week before planting. This simple step can make the difference between success and failure.
Overwatering In Cool Weather
Plants need less water as temperatures drop. Overwatering leads to root rot and fungal diseases. Water only when the top inch of soil feels dry.
Mulch helps regulate moisture levels. It also keeps soil from getting waterlogged during fall rains.
Frequently Asked Questions
What vegetables can I plant in September in Minnesota?
You can plant spinach, kale, arugula, lettuce, radishes, carrots, beets, broccoli, and cauliflower. These vegetables tolerate cool weather and mature before hard frost.
Is it too late to plant vegetables in September in Minnesota?
No, it’s not too late if you choose fast-maturing varieties. Focus on crops that mature in 30-60 days. Use transplants for slower-growing vegetables like broccoli.
How do I protect September vegetables from frost?
Use row covers, cloches, or cold frames to protect plants from frost. Cover them before sunset on cold nights and remove covers in the morning. Mulch also helps insulate soil.
Can I plant tomatoes in September in Minnesota?
Tomatoes are not suitable for September planting. They need warm soil and long days to produce fruit. Focus on cold-hardy vegetables instead.
What is the best way to prepare soil for fall vegetables?
Remove summer plants and weeds, then add 2 inches of compost. Work it into the top 6 inches of soil. Test pH and adjust if needed. Warm soil with black plastic if planting late.
September gardening in Minnesota is a race, but one you can win. The best vegetables to plant in september in minnesota are those that grow fast and handle cold. With the right choices and a little protection, you’ll enjoy fresh produce long after summer ends.
Start with leafy greens and root vegetables for quick results. Add transplants of broccoli or kale for a longer harvest. Use row covers and mulch to extend your season. Your fall garden can be just as productive as your summer one.
Get out there and plant. The cool air and warm soil are waiting. Your September garden will reward you with crisp, sweet vegetables that taste like autumn itself.