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When to Plant Sunflower in Monroe County, TN

Monroe County, Tennessee Zone 7b July

What to do in July

Your garden in Monroe County, Tennessee is working on a schedule, even when you're not. Here's where you should be this July.

Avg. last frost April 9
Avg. first frost October 23
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 14.2 hrs
  1. Bring in the sunflower

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Coming up in August — start thinking about
  • First harvests: sunflower

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Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.

Monroe County, Tennessee is in USDA Zone 7b. The average last spring frost is April 9 and the first fall frost is October 23, giving you a growing season of approximately 197 days.

At an elevation of 3,185 feet, Monroe County receives approximately 48.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Sunflower during the growing season.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Monroe County, TN (Zone 7b) Moderate season
197 days
Last Spring Frost April 9
197 growing days
First Fall Frost October 23

Monroe County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.8

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Mar 14 Transplant: Apr 4 🌸 Bloom: Jun 27 – Oct 17
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Mar 19 Transplant: Apr 9 🌸 Bloom: Jul 2 – Oct 22
Safe Start (90%) ✗ May not fit
Start indoors: Apr 8 Transplant: Apr 29 🌸 Bloom: Jul 22 – Nov 11

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 Monroe County

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

Soil pH

Your soil pH (5.4–6.8) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Monroe County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

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

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Sunflower

3
successive plantings in your 197-day season

Sow every 8 weeks. Last sowing by Jul 15 to harvest before frost.

Sunflower Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Sunflower

Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sunflower Needs Rainfall You Supplement Action
Jan 3.8" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 2.2" 3.3" 0" ✅ Rainfall sufficient
May 2.2" 3.7" 0" ✅ Rainfall sufficient
Jun 2.2" 4.9" 0" ✅ Rainfall sufficient
Jul 2.2" 5.4" 0" ✅ Rainfall sufficient
Aug 2.2" 5.2" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.8" 0" ✅ Rainfall sufficient
Nov 3.8" 0" ❄️ Dormant
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Monroe County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sunflower 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" — every day above 50°F 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.

Sunflower needs ~1,360 GDD — county provides 3,152 GDD Excellent fit

Sunflower Planting Timeline — Monroe County, TN

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 9 Apr 9 – Apr 23
Direct Sow April 9 Apr 9 – Apr 30
Bloom July 2 Jul 2 – Oct 22

Plant 1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May
June
July Bloom
August Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

197 days in Monroe County

Growing Tips for Sunflower in Monroe County

Direct sow Sunflower outdoors after April 09 in Monroe County when soil has warmed and frost danger has passed.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Pole_beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Monroe County, TN?

Monroe County is in Zone 7b with an average last frost of April 9. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monroe County, TN?

Monroe County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 9 and first fall frost is October 23.

🌱

Your Monroe County Garden Planner — Free

A 22-page printable planner built for Monroe County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.