When To Plant Brussel Sprouts In Missouri

Getting your timing right is the most important step for growing brussel sprouts in Missouri. Knowing exactly when to plant brussel sprouts in Missouri makes the difference between a bountiful harvest and disappointment.

These cool-season crops thrive in Missouri’s spring and fall, but our weather can be tricky. This guide gives you the clear, simple schedule you need for success.

We’ll cover both spring and autumn planting, plus tips for dealing with our unique climate.

For a fall harvest, which is often the most reliable in Missouri, you need to work backwards from your first frost date. The key is to get the plants established before summer heat fades, so they mature in cool weather.

For most of Missouri, the ideal planting times are:

Spring Planting: Transplant seedlings outdoors 2-4 weeks before your last average spring frost date. This is usually early to mid-April for central Missouri. Seeds should be started indoors 4-6 weeks before that transplant date.
Fall Planting (Recommended): Transplant seedlings outdoors in mid-July to early August. This timing is critical for a harvest after frost. You’ll start those seeds indoors in late June to early July.

Brussel sprouts need a long growing season—often 90-110 days from transplanting. Planting too late in spring means they hit summer heat just as they’re trying to form sprouts, which causes poor development.

Understanding Missouri’s Frost Dates

Your local frost dates are your best gardening calendar. Missouri’s climate varies from USDA Zone 5b in the north to Zone 7a in the south.

Northern MO (e.g., Kirksville): Last frost around April 15-25; First frost around October 10-20.
Central MO (e.g., Columbia, Jefferson City): Last frost around April 10-15; First frost around October 15-25.
Southern MO (e.g., Springfield, Poplar Bluff): Last frost around April 5-10; First frost around October 20-30.

Always use your specific city for the most accurate planning. A light fall frost actually improves the flavor of the sprouts, making them sweeter.

Step-by-Step: Starting Seeds Indoors

Starting your own seeds gives you control over timing and variety. Here’s how to do it.

Calculate Your Date: For a fall crop, count back 12-14 weeks from your first fall frost date. That’s your seed starting date. For example, if your frost is October 20, start seeds around July 10.
Plant the Seeds: Sow seeds ¼ inch deep in a quality seed-starting mix. Use cell trays or small pots. Keep the soil consistently moist but not soggy.
Provide Light & Warmth: Place them in a warm spot (70-75°F). Once they sprout, they need strong light—a sunny south window or grow lights for 12-14 hours a day to prevent leggy seedlings.
Transplant Seedlings: When seedlings have 4-6 true leaves and are about 5-6 inches tall, they are ready to harden off. This takes about 4-6 weeks from seeding.

Hardening Off and Transplanting Outdoors

Never move tender seedlings straight to the garden. They need a gentle transition called hardening off.

About 7-10 days before transplanting, begin placing your seedlings outdoors in a shaded, sheltered spot for a few hours.
Gradually increase their time outside and their exposure to direct sunlight over the week.
By the end, they should be able to handle full sun and overnight conditions.
Transplant on a cloudy day or in the late afternoon to reduce shock. Space plants 18-24 inches apart in rows 30 inches apart. They get big!

Water them in well with a starter fertilizer to help with root establishment. A little stress at this stage can set them back weeks.

Choosing the Right Location and Soil

Brussel sprouts are heavy feeders. They need rich soil and full sun—at least 6 hours of direct sunlight daily.

Soil Prep: Work in 3-4 inches of compost or well-rotted manure before planting. The soil should be fertile, well-draining, and have a pH between 6.0 and 7.0.
Fertilizing: Use a balanced organic fertilizer at planting. Side-dress with a nitrogen-rich fertilizer when plants are about 12 inches tall, and again when they begin to form sprouts.
Watering: Provide 1-1.5 inches of water per week. Consistent moisture is vital, especially during sprout formation. Mulch heavily to retain moisture and keep soil cool.

Seasonal Care Through Missouri’s Weather

Summer heat and pests are your main challenges. Here’s how to manage them.

Managing Summer Heat

For spring-planted crops, a sudden heatwave can stunt growth. Use shade cloth during the hottest part of the afternoon if temperatures soar above 85°F consistently. The mulch you applied will also help keep roots cooler.

For fall crops, the young plants will endure summer’s end. Ensure they get enough water to get established through the July and August heat.

Common Pests and Problems

Aphids, cabbage loopers, and imported cabbageworms love brussel sprouts. Check the undersides of leaves regularly.

Use floating row covers immediately after transplanting to prevent moths from laying eggs.
For infestations, apply Bacillus thuringiensis (Bt), a natural bacteria that targets caterpillars.
A strong spray of water can dislodge aphids. Encourage beneficial insects like ladybugs.

Also, practice crop rotation. Don’t plant them where other cabbage family plants grew the previous year to reduce soil-borne disease.

The Harvest: Your Reward

Harvest begins from the bottom of the stalk upward. Pick sprouts when they are firm, about 1-1.5 inches in diameter.

Twist or cut them off the stem. A few light frosts will sweeten the flavor. Before a hard freeze (below 20°F), you can harvest the entire stalk by cutting it at the base.

You can then hang it in a cool garage or basement for several weeks of continued harvesting. Some gardeners even dig up the whole plant and replant it in a bucket of soil in a root cellar.

Recommended Varieties for Missouri

Choose varieties with maturity dates that fit your planting window. Some reliable ones include:

‘Long Island Improved’: A reliable standard, good for fall harvests.
‘Jade Cross E’: Hybrid, disease-resistant, and compact.
‘Churchill’: Early maturing (about 90 days), good for trying a spring crop.
‘Diablo’: Known for its excellent flavor and high yield.

Experiment to see which one performs best in your specific garden microclimate. Local nurseries often carry varieties suited to the area.

FAQ: Your Missouri Brussel Sprout Questions Answered

Can I plant brussel sprouts directly in the garden in Missouri?
It’s not recommended. The long growing season and need for precise timing make starting seeds indoors the best method for control. Direct sowing is less reliable here.

What if I miss the ideal fall planting window?
If you’re only a week or two late, go ahead and plant. Choose a faster-maturing variety. If it’s late August or September, it’s probably to late for most of Missouri, as the plants won’t mature before a hard freeze stops growth.

Why are my brussel sprouts not forming tight buds?
This is usually caused by too much nitrogen late in the season, inconsistent watering, or, most commonly, heat stress. This is why fall planting is often more succesful—the sprouts form as temperatures drop.

Do brussel sprouts come back every year?
No, they are biennials grown as annuals. They complete their life cycle—sprouting, growing, and producing seeds—over two years, but we harvest them in the first year.

How do I protect my fall crop from an early freeze?
You can cover the plants with a thick row cover or old blankets when a light early frost is forecasted. This can extend your harvest season by a few weeks. For a hard freeze, it’s best to harvest the entire stalk.