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When to Plant Microgreens in Hamblen County, TN

Hamblen County, Tennessee Zone 7b May

May to-do list for Hamblen County, Tennessee

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

Avg. last frost April 15
Avg. first frost October 22
Soil temp (4") 61°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Get microgreens seeds going inside

    You're about 22 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. It's harvest week for microgreens

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

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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.

Hamblen County, Tennessee is in USDA Zone 7b. The average last spring frost is April 15 and the first fall frost is October 22, giving you a growing season of approximately 190 days.

At an elevation of 3,052 feet, Hamblen County receives approximately 48.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Microgreens during the growing season.

Hamblen County, TN (Zone 7b) Moderate season
190 days
Last Spring Frost April 15
190 growing days
First Fall Frost October 22
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Hamblen County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (158 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: Apr 15 – May 13
Recommended (50%) ✓ Fits season (155 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Apr 22 – May 20
Safe Start (90%) ✓ Fits season (150 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: May 9 – Jun 6

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 Hamblen County

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

Soil pH

Your soil pH (5.5–6.8) overlaps with Microgreens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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

37
successive plantings in your 190-day season

Sow every 0.7 weeks. Last sowing by Oct 01 to harvest before frost.

For a dedicated fall crop, sow by Aug 13.

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 3.3" 0" ❄️ Dormant
Mar 4" 0" ❄️ Dormant
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 4.2" 0" ❄️ Dormant
Dec 4.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hamblen 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 ~256 GDD — county provides 3,467 GDD Excellent fit

Microgreens Planting Timeline — Hamblen County, TN

Microgreens Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 15 Apr 15 – Apr 29
Direct Sow April 1 Apr 1 – Apr 22
Harvest April 22 Apr 22 – May 20
Fall Sowing August 13 Aug 13 – Aug 27

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

Month-by-Month Timeline

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

190 days in Hamblen County

Growing Tips for Microgreens in Hamblen County

Direct sow Microgreens outdoors after April 15 in Hamblen County when soil has warmed and frost danger has passed.

Your generous 190.0-day season in Hamblen 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 Hamblen County, TN?

Hamblen County is in Zone 7b with an average last frost of April 15. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamblen County, TN?

Hamblen County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 15 and first fall frost is October 22.

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Your Hamblen County Garden Planner — Free

A 24-page printable planner built for Hamblen 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 Hamblen 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.