Zone 6b Planting Guide 2026 | St. Louis, Nashville, Lexington Garden Calendar

Zone 6b's 170-to-200-day season is long enough for almost anything — including a second fall garden most gardeners never plant. The catch is heat and humidity: warm-spring head fakes and bolting greens. Here are your 2026 dates, frost windows, and best varieties.

USDA Hardiness Zone 6b at a glance

Minimum temperature

-5°F to 0°F (-20.6°C to -17.8°C)

Average last frost

April 3 (range March 25 – April 10)

Average first fall frost

October 20 – November 5

Growing season

170 – 200 days

Best planting window

April 10 – 25 for warm-season crops

Where it falls

St. Louis, Nashville, Lexington, Tulsa, Wichita

Major cities in Zone 6b

Primary cities: St. Louis, MO • Nashville, TN • Lexington, KY • Tulsa, OK • Wichita, KS • Evansville, IN

Also includes: Parts of Missouri, Tennessee, Kentucky, Oklahoma, Kansas, southern Indiana, and southern Illinois.

Try our Free Vegetable Planting Calendar by ZIP Code

Enter your ZIP code for a free, personalized planting calendar. See when to start seeds, transplant, and harvest 45+ vegetables, herbs, and flowers based on your USDA hardiness zone and frost dates.

Open Planting Calendar

2026 Zone 6b Planting Calendar

February — early indoor starting

Crop	Start Date	Transplant Date	Notes
Tomatoes	Feb 20 - March 10	April 15-30	Wide variety selection works here
Peppers	Feb 15 - March 5	April 20 - May 5	Even superhots are feasible
Eggplant	Feb 25 - March 10	April 25 - May 5	Needs warm soil (65°F+)
Herbs (Basil)	March 5-20	April 20 - May 5	Wait until nights stay above 50°F

March — cool-season crops

Crop	Direct Sow Date	Harvest	Notes
Peas	March 10-25	May-June	One of the first crops to go in
Lettuce	March 15 - April 5	May-June	Succession plant every 2 weeks
Spinach	March 10-25	May-June	Sow early — bolts in heat
Radishes	March 15 - April 5	April-May	Quick 25-day harvest
Carrots	March 20 - April 15	June-August	Deep, loose soil preferred

April–May — warm-season planting

Crop	Plant Date	Harvest Start	Notes
Beans (Bush)	April 20 - May 15	June-August	Direct sow in warm soil
Corn	April 25 - May 15	July-September	Full-season varieties work well
Squash (Summer)	April 20 - May 10	June-September	Long harvest window
Cucumbers	April 20 - May 10	June-September	Trellis for best results
Melons	May 1-15	August-September	Plenty of heat for cantaloupes

Best Varieties for Zone 6b

Tomatoes — excellent range

Better Boy (72 days): Classic slicer, heavy producer
Cherokee Purple (80 days): Rich heirloom flavor
San Marzano (80 days): Best paste tomato
Brandywine (90 days): Enough season for this long-season heirloom
Cherry tomatoes: Sun Gold, Super Sweet 100, Black Cherry

Peppers — full range available

Sweet: California Wonder, Lunchbox, Giant Marconi
Mild Hot: Poblano, Anaheim, Shishito
Medium Hot: Jalapeño, Serrano, Cayenne
Superhot: Habanero, Ghost Pepper (start indoors by Feb 1)

Cool-season stars

Lettuce: Buttercrunch, Romaine, Salanova mixes
Spinach: Bloomsdale, Tyee, Corvair
Peas: Sugar Snap, Snow Peas, Cascadia
Carrots: Nantes, Danvers, Bolero

Zone 6b Frost Information

Critical frost dates for 2026

Last spring frost

April 3 average (range March 25 – April 10)

Safe planting date

April 10 – 20 (add 1 week for safety)

First fall frost

October 28 average (range October 20 – November 5)

Latest recorded spring frost

April 22 (St. Louis area)

2026 climate considerations

Warm springs: Zone 6b often gets early warm spells — resist the urge to plant too early
Summer heat: July-August regularly hits 95°F+ — heat-tolerant varieties recommended
Humidity: Higher humidity east of the Mississippi increases disease pressure
Long fall: Extended mild fall allows late-season succession planting

Frost protection strategies

Row covers: Light fabric adds 4-6°F, good for early transplants
Hardening off: Zone 6b springs are changeable — take a full 7-10 days
Raised beds: Warm 1-2 weeks earlier than in-ground
Season extension: Low tunnels can push the fall harvest into November

Zone 6b Success Tips

Soil and site preparation

Soil test: Missouri and Tennessee soils range widely — test before amending
Drainage: Clay soils are common in the mid-South — raised beds help
pH: Many zone 6b soils are slightly acidic (6.0-6.5) — ideal for most vegetables
Organic matter: Add 2-3 inches of compost annually

Season extension techniques

Start seeds indoors: 8-10 weeks before last frost for warm-season crops
Fall planting: Zone 6b has a long enough fall for second plantings of lettuce, spinach, kale, and beets in August
Succession planting: Stagger beans, lettuce, and radishes every 2-3 weeks
Winter greens: Cold frames and low tunnels keep spinach and kale growing into December

Common Zone 6b mistakes

Planting too early after a warm spell: March warmth doesn't mean the last frost has passed
Ignoring summer heat: Lettuce and spinach bolt fast — plan for shade cloth or heat-tolerant varieties
Skipping fall gardens: The long zone 6b fall is a huge opportunity most gardeners miss
Overwatering clay soil: Leads to root rot — water deeply but less frequently

Monthly Zone 6b Garden Tasks

February

Start pepper and eggplant seeds indoors
Order seeds and plan garden layout
Prune dormant fruit trees and berry bushes

March

Start tomato seeds indoors
Direct sow peas, lettuce, spinach, radishes outdoors
Prepare beds with compost
Set up trellises for peas

April

Transplant tomatoes, peppers, eggplant after last frost
Direct sow beans, corn, squash
Continue succession planting cool-season crops
Mulch around transplants

May

Plant melons, sweet potatoes, and okra
Side-dress established plants with compost
Install drip irrigation before summer heat
Monitor for early pest pressure

Get your exact dates

Zone 6b's warm spells make timing tricky. Use the free Planting Calendar for personalized variety recommendations and frost alerts for your ZIP code.

Last updated: March 6, 2026 | Zone 6b data based on USDA Plant Hardiness Zone Map 2023 and NOAA climate normals.