When to Plant Mustard Greens in Union County, TN
Your May planting checklist for Union County, Tennessee
Your Union 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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Sow mustard greens in trays indoors
Label every cell. You will absolutely forget which is which otherwise.
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It's harvest week for mustard greens
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
To set up a strong June, finish these tasks
- First harvests: mustard greens
Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.
Union County, Tennessee is in USDA Zone 7b. The average last spring frost is April 10 and the first fall frost is October 29, giving you a growing season of approximately 202 days.
At an elevation of 1,122 feet, Union County receives approximately 50.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Mustard Greens during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Mustard Greens root diseases.
Union County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.6
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 Union County
How your county's soil matches Mustard Greens's growing requirements.
Soil pH
Your soil pH (5.8–6.6) overlaps with Mustard Greens's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Union County is excellent for Mustard Greens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.9%). Annual compost additions will help Mustard Greens.
How to Plant Mustard Greens
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Mustard Greens
Sow every 3.4 weeks. Last sowing by Sep 09 to harvest before frost.
For a dedicated fall crop, sow by Aug 20.
Plant Water Budget
Monthly Watering Guide for Mustard Greens
Mustard Greens needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Mustard Greens Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 4.8" | 0" | ❄️ Dormant |
| Feb | — | 3.4" | 0" | ❄️ Dormant |
| Mar | — | 5.2" | 0" | ❄️ Dormant |
| Apr | 3" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 3" | 3.7" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 5.6" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 4.1" | 0" | ✅ Rainfall sufficient |
| Oct | 3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3.4" | 0" | ❄️ Dormant |
| Dec | — | 4.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Union County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Mustard Greens 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.
Mustard Greens Planting Timeline — Union County, TN
Mustard Greens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 6 | Mar 6 – Mar 20 |
| Transplant Outdoors | April 10 | Apr 10 – Apr 24 |
| Direct Sow | March 27 | Mar 27 – Apr 17 |
| Harvest | May 15 | May 15 – Jul 17 |
| Fall Sowing | August 20 | Aug 20 – Sep 3 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
30–50 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
202 days in Union County
Growing Tips for Mustard Greens in Union County
Direct sow Mustard Greens outdoors after April 10 in Union County when soil has warmed and frost danger has passed.
Your generous 202.0-day season in Union County allows multiple plantings of Mustard Greens. Sow every 15.0 days for continuous harvest.
Common pests for Mustard Greens in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow in early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Mustard Greens in Other Locations
Frequently Asked Questions
When should I plant Mustard Greens in Union County, TN?
Union County is in Zone 7b with an average last frost of April 10. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, TN?
Union County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 10 and first fall frost is October 29.
Your Union County Garden Planner — Free
A 24-page printable planner built for Union 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.