When to Plant Arugula in Grainger County, TN
What to do in May
Your Grainger County, Tennessee garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
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Indoor seed-starting week for arugula
These need a head start before your last frost (April 15). Sow into cells now so you're ready to transplant in a few weeks.
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Bring in the arugula
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Before June arrives, get these ready
- First harvests: arugula
Arugula is a fast-growing cool-season green with a peppery, nutty flavor. It is excellent in salads and can be harvested as baby greens or mature leaves.
Grainger 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 3,009 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 Arugula 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 Arugula's growing requirements.
Soil pH
Your soil pH (5.5–6.8) overlaps with Arugula's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Grainger County is excellent for Arugula — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.2%). Annual compost additions will help Arugula.
How to Plant Arugula
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Arugula
Sow every 3.4 weeks. Last sowing by Sep 02 to harvest before frost.
For a dedicated fall crop, sow by Aug 13.
Plant Water Budget
Monthly Watering Guide for Arugula
Arugula needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.
| Month | Arugula Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 4.1" | 0" | ❄️ Dormant |
| Feb | — | 3.6" | 0" | ❄️ Dormant |
| Mar | — | 4.9" | 0" | ❄️ Dormant |
| Apr | 2.6" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 4" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 5.3" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 5.2" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 3.3" | 0" | ✅ Rainfall sufficient |
| 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.
Arugula 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.
Arugula Planting Timeline — Grainger County, TN
Arugula 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 | May 20 | May 20 – Jul 22 |
| Fall Sowing | August 13 | Aug 13 – Aug 27 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.6"/week · Natural rainfall sufficient
📅 Days to Maturity
30–50 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
190 days in Grainger County
Growing Tips for Arugula in Grainger County
Direct sow Arugula outdoors after April 15 in Grainger County when soil has warmed and frost danger has passed.
Summer highs in Grainger County reach 92°F — grow Arugula as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 190.0-day season in Grainger County allows multiple plantings of Arugula. Sow every 15.0 days for continuous harvest.
Common pests for Arugula in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Sow seeds directly every 2-3 weeks for continuous harvest. Provide afternoon shade in warm weather to prevent bolting. Harvest outer leaves first to extend production.
Companion Planting
Good Companions
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Check more plant combinations with our Companion Planting Checker →
Arugula in Other Locations
Frequently Asked Questions
When should I plant Arugula in Grainger County, TN?
Grainger County is in Zone 7b with an average last frost of April 15. Plan your Arugula 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 7b. The average last spring frost is April 15 and first fall frost is October 22.
Your Grainger County Garden Planner — Free
A 24-page printable planner built for Grainger 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.