When to Plant Arugula in Mercer County, MO
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.
Mercer County, Missouri is in USDA Zone 5b. The average last spring frost is April 20 and the first fall frost is October 14, giving you a growing season of approximately 177 days.
At an elevation of 523 feet, Mercer County receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Arugula during the growing season.
Mercer County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.8
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.
Plant Water Budget
Arugula Planting Timeline — Mercer County, MO
Arugula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 16 | Mar 16 – Mar 30 |
| Transplant Outdoors | April 20 | Apr 20 – May 4 |
| Direct Sow | April 6 | Apr 6 – Apr 27 |
| Fall Sowing | August 5 | Aug 5 – Aug 19 |
| Harvest | May 25 | May 25 – Jul 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 | Transplant Outdoors Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Partial Shade (3-6 hours)
Water
Moderate — regular watering
Days to Maturity
30–50 days
Soil pH
6 – 7
USDA Zone
Zone 5b
Growing Season
177 days
Growing Tips for Mercer County
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
Avoid Planting Near
Level Up Your Garden
Arugula in Other Locations
Frequently Asked Questions
When should I plant Arugula in Mercer County, MO?
Mercer County is in Zone 5b with an average last frost of April 20. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mercer County, MO?
Mercer County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 20 and first fall frost is October 14.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Mercer County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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