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When to Plant Tomatoes in Dunklin County, MO

Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Dunklin County, Missouri is in USDA Zone 7a. The average last spring frost is March 27 and the first fall frost is November 2, giving you a growing season of approximately 220 days.

At an elevation of 1,344 feet, Dunklin County receives approximately 33.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94ยฐF, providing good warmth for Tomatoes during the growing season.

Dunklin County, MO (Zone 7a) Long season
220 days
Last Spring Frost March 27
220 growing days
First Fall Frost November 2

Dunklin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Jan 29 Transplant: Apr 2 🍅 Harvest: Jun 4 – Aug 13
Recommended (50%) ✓ Fits season (73 days to spare)
Start indoors: Feb 6 Transplant: Apr 10 🍅 Harvest: Jun 12 – Aug 21
Safe Start (90%) ✓ Fits season (73 days to spare)
Start indoors: Feb 26 Transplant: Apr 30 🍅 Harvest: Jul 2 – Sep 10

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Dunklin County

How your county's soil matches Tomatoes's growing requirements.

Soil pH

Your soil pH (5.6โ€“7.1) overlaps with Tomatoes's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Dunklin County is excellent for Tomatoes โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Tomatoes.

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

4
successive plantings in your 220-day season

Sow every 6.9 weeks. Last sowing by Aug 09 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.6″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,097 gal / 100 sq ft

Monthly Watering Guide for Tomatoes

Tomatoes needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Tomatoes Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar 5.2" 2.4" 2.8" ๐Ÿšฟ Regular watering
Apr 5.2" 2.8" 2.4" ๐Ÿ’ง Light watering
May 5.2" 4.1" 1.1" ๐Ÿ’ง Light watering
Jun 5.2" 4.3" 0.9" ๐Ÿ’ง Light watering
Jul 5.2" 3.7" 1.5" ๐Ÿ’ง Light watering
Aug 5.2" 3.5" 1.7" ๐Ÿ’ง Light watering
Sep 5.2" 3.2" 2" ๐Ÿ’ง Light watering
Oct 5.2" 2.8" 2.4" ๐Ÿ’ง Light watering
Nov 5.2" 2.4" 2.8" ๐Ÿšฟ Regular watering
Dec โ€” 1.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Dunklin County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Tomatoes Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Tomatoes needs ~1,486 GDD — county provides 4,510 GDD Excellent fit

Tomatoes Planting Timeline โ€” Dunklin County, MO

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors February 6 Feb 6 โ€“ Feb 20
Transplant Outdoors April 10 Apr 10 โ€“ Apr 24
Direct Sow April 3 Apr 3 โ€“ Apr 24
Harvest June 12 Jun 12 โ€“ Aug 21

Plant 0.5" deep ยท 24" apart ยท Rows 36" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March โ€”
April Transplant Outdoors Direct Sow
May โ€”
June Harvest
July Harvest
August Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.2"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

60โ€“85 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 7a

๐Ÿ“† Growing Season

220 days in Dunklin County

Growing Tips for Tomatoes in Dunklin County

Direct sow Tomatoes outdoors after March 27 in Dunklin County when soil has warmed and frost danger has passed.

Common pests for Tomatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Check more plant combinations with our Companion Planting Checker →

๐ŸŒพ Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35ยฐF, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Dunklin County, MO?

Dunklin County is in Zone 7a with an average last frost of March 27. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Dunklin County, MO?

Dunklin County, Missouri is in USDA Hardiness Zone 7a. The average last spring frost is March 27 and first fall frost is November 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Dunklin County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Dunklin County, MO. Local conditions may vary. Last updated: April 2026.