Blog

When to Plant Onion in Lincoln County, TN

Lincoln County, Tennessee Zone 7b May

Your May planting checklist for Lincoln County, Tennessee

We've pulled the most time-sensitive tasks for Lincoln County, Tennessee this May and put them front and centre. Tackle them in order.

Avg. last frost April 9
Avg. first frost October 26
Soil temp (4") 59°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Start onion under lights

    Label every cell. You will absolutely forget which is which otherwise.

Instant PDF download. No spam, unsubscribe any time.

Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

Lincoln County, Tennessee is in USDA Zone 7b. The average last spring frost is April 9 and the first fall frost is October 26, giving you a growing season of approximately 200 days.

At an elevation of 3,458 feet, Lincoln County receives approximately 51.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Onion during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.

Lincoln County, TN (Zone 7b) Long season
200 days
Last Spring Frost April 9
200 growing days
First Fall Frost October 26
Share this guide:

Lincoln County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (61 days to spare)
Start indoors: Feb 26 Transplant: Apr 2 🍅 Harvest: Jul 2 – Aug 20
Recommended (50%) ✓ Fits season (60 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jul 9 – Aug 27
Safe Start (90%) ✓ Fits season (63 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jul 22 – Sep 9

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 Lincoln County

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

Soil pH

Your soil pH (5.3–6.6) is more acidic than Onion prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Onion.

How to Plant Onion

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

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

Monthly Watering Guide for Onion

Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Onion Needs Rainfall You Supplement Action
Jan 3.9" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 4.4" 0" ❄️ Dormant
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 5.3" 0" ✅ Rainfall sufficient
Jul 4.3" 5.9" 0" ✅ Rainfall sufficient
Aug 4.3" 5.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 3.5" 0" ❄️ Dormant
Dec 4.4" 0" ❄️ Dormant

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

Onion 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.

Onion needs ~2,074 GDD — county provides 3,950 GDD Excellent fit

Onion Planting Timeline — Lincoln County, TN

Onion Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors April 9 Apr 9 – Apr 23
Direct Sow March 26 Mar 26 – Apr 16
Harvest July 9 Jul 9 – Aug 27
Fall Sowing August 17 Aug 17 – Aug 31

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May
June
July Harvest
August Fall Sowing Harvest
September
October
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7b

📆 Growing Season

200 days in Lincoln County

Growing Tips for Onion in Lincoln County

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

Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in Lincoln County, TN?

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

What planting zone is Lincoln County, TN?

Lincoln County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 9 and first fall frost is October 26.

🌱

Your Lincoln County Garden Planner — Free

A 24-page printable planner built for Lincoln 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 Lincoln County, TN. Local conditions may vary. Last updated: May 2026.

Sources & credits

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