When to Plant Microgreens in Grainger County, TN
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.
Grainger County, Tennessee is in USDA Zone 7a. 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 3,009 feet, Grainger County receives approximately 49.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Microgreens during the growing season.
Grainger County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.8
Drainage
Well Drained
Plant Planting Risk Windows
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 Grainger 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 Grainger County is excellent for Microgreens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.2%). Annual compost additions will help Microgreens.
How to Plant Microgreens
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Microgreens
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
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 | — | 4.1" | 0" | ❄️ Dormant |
| Feb | — | 3.6" | 0" | ❄️ Dormant |
| Mar | — | 4.9" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| May | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jul | 4.3" | 5.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 5.2" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Oct | 4.3" | 3.3" | 1" | 💧 Light watering |
| Nov | — | 3.7" | 0" | ❄️ Dormant |
| Dec | — | 3.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Grainger 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 Planting Timeline — Grainger 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
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | Fall Sowing |
| September | — |
| 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 7a
📆 Growing Season
190 days in Grainger County
Growing Tips for Microgreens in Grainger County
Direct sow Microgreens outdoors after April 15 in Grainger County when soil has warmed and frost danger has passed.
Your generous 190.0-day season in Grainger 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.
Microgreens in Other Locations
Frequently Asked Questions
When should I plant Microgreens in Grainger County, TN?
Grainger County is in Zone 7a 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 Grainger County, TN?
Grainger County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 15 and first fall frost is October 22.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Grainger County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.
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