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When to Plant Tomatoes in Grundy County, TN

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.

Grundy County, Tennessee is in USDA Zone 7a. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.

At an elevation of 1,205 feet, Grundy County receives approximately 47.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92ยฐF, providing good warmth for Tomatoes during the growing season.

Grundy County, TN (Zone 7a) Long season
206 days
Last Spring Frost April 6
206 growing days
First Fall Frost October 29

Grundy County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (61 days to spare)
Start indoors: Feb 8 Transplant: Apr 12 🍅 Harvest: Jun 14 – Aug 23
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Feb 16 Transplant: Apr 20 🍅 Harvest: Jun 22 – Aug 31
Safe Start (90%) ✓ Fits season (60 days to spare)
Start indoors: Mar 1 Transplant: May 3 🍅 Harvest: Jul 5 – Sep 13

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 Grundy County

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

Soil pH

Your soil pH (5.5โ€“6.7) overlaps with Tomatoes's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). 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 206-day season

Sow every 6.9 weeks. Last sowing by Aug 05 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
1.0″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 413 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€” 4.2" 0" โ„๏ธ Dormant
Feb โ€” 3.7" 0" โ„๏ธ Dormant
Mar โ€” 5.4" 0" โ„๏ธ Dormant
Apr 5.2" 3.8" 1.4" ๐Ÿ’ง Light watering
May 5.2" 3.9" 1.3" ๐Ÿ’ง Light watering
Jun 5.2" 4.4" 0.8" ๐Ÿ’ง Light watering
Jul 5.2" 5.1" 0.1" ๐Ÿ’ง Light watering
Aug 5.2" 4.3" 0.9" ๐Ÿ’ง Light watering
Sep 5.2" 3.2" 2" ๐Ÿ’ง Light watering
Oct 5.2" 2.7" 2.5" ๐Ÿ’ง Light watering
Nov โ€” 3.6" 0" โ„๏ธ Dormant
Dec โ€” 3.6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Grundy 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 ~1,378 GDD — county provides 3,914 GDD Excellent fit

Tomatoes Planting Timeline โ€” Grundy County, TN

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 โ€“ Mar 2
Transplant Outdoors April 20 Apr 20 โ€“ May 4
Direct Sow April 13 Apr 13 โ€“ May 4
Harvest June 22 Jun 22 โ€“ Aug 31

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
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 Only during dry spells

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

206 days in Grundy County

Growing Tips for Tomatoes in Grundy County

Direct sow Tomatoes outdoors after April 06 in Grundy 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 Grundy County, TN?

Grundy County is in Zone 7a with an average last frost of April 6. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grundy County, TN?

Grundy County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 6 and first fall frost is October 29.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Grundy 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 Grundy County, TN. Local conditions may vary. Last updated: April 2026.