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When to Plant Microgreens in Hardin County, TN

Hardin County, Tennessee Zone 7b May

Your May game plan for Hardin County, Tennessee

May is a pivotal month for Hardin County, Tennessee gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost March 31
Avg. first frost October 28
Soil temp (4") 62°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Sow microgreens in trays indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Collect microgreens at their peak

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Hardin County, Tennessee is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is October 28, giving you a growing season of approximately 211 days.

At an elevation of 3,095 feet, Hardin County receives approximately 53.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Microgreens during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Microgreens root diseases.

Hardin County, TN (Zone 7b) Long season
211 days
Last Spring Frost March 31
211 growing days
First Fall Frost October 28

Hardin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (179 days to spare)
Start indoors: Feb 17 Transplant: Mar 24 🍅 Harvest: Mar 31 – Apr 28
Recommended (50%) ✓ Fits season (176 days to spare)
Start indoors: Feb 24 Transplant: Mar 31 🍅 Harvest: Apr 7 – May 5
Safe Start (90%) ✓ Fits season (176 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Apr 23 – May 21

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 Hardin County

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

Soil pH

Your soil pH (5.4–6.7) overlaps with Microgreens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Microgreens.

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Microgreens

41
successive plantings in your 211-day season

Sow every 0.7 weeks. Last sowing by Oct 07 to harvest before frost.

For a dedicated fall crop, sow by Aug 19.

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 Microgreens

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

Month Microgreens Needs Rainfall You Supplement Action
Jan 4.2" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 4.3" 5.2" 0" ✅ Rainfall sufficient
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 6" 0" ✅ Rainfall sufficient
Aug 4.3" 4.9" 0" ✅ Rainfall sufficient
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3.9" 0.4" 💧 Light watering
Nov 4.3" 0" ❄️ Dormant
Dec 4.1" 0" ❄️ Dormant

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

Microgreens 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.

Microgreens needs ~276 GDD — county provides 4,167 GDD Excellent fit

Microgreens Planting Timeline — Hardin County, TN

Microgreens Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors March 31 Mar 31 – Apr 14
Direct Sow March 17 Mar 17 – Apr 7
Harvest April 7 Apr 7 – May 5
Fall Sowing August 19 Aug 19 – Sep 2

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

211 days in Hardin County

Growing Tips for Microgreens in Hardin County

Direct sow Microgreens outdoors after March 31 in Hardin County when soil has warmed and frost danger has passed.

Your generous 211.0-day season in Hardin County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Hardin County, TN?

Hardin County is in Zone 7b with an average last frost of March 31. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hardin County, TN?

Hardin County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is October 28.

🌱

Your Hardin County Garden Planner — Free

A 24-page printable planner built for Hardin 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Hardin 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.