When to Plant Arugula in Caldwell County, MO
May in Caldwell County, Missouri — your action list
Welcome to May in Zone 6a. These are the moves that will have the biggest impact on your growing season.
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Start arugula indoors
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
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Pick arugula
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
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.
Caldwell County, Missouri is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 22, giving you a growing season of approximately 192 days.
At an elevation of 1,389 feet, Caldwell County receives approximately 34 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Arugula to ensure they mature before fall.
Caldwell County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-7.1
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 Caldwell County
How your county's soil matches Arugula's growing requirements.
Soil pH
Your soil pH (5.6–7.1) overlaps with Arugula's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Caldwell County is excellent for Arugula — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). 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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.2" | 0" | ❄️ Dormant |
| Apr | 2.6" | 3.2" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 3.9" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 3.3" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 2.5" | 0.1" | 💧 Light watering |
| Nov | — | 2.1" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Caldwell 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 — Caldwell County, MO
Arugula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 9 | Mar 9 – Mar 23 |
| Transplant Outdoors | April 13 | Apr 13 – Apr 27 |
| Direct Sow | March 30 | Mar 30 – Apr 20 |
| Harvest | May 18 | May 18 – Jul 20 |
| 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 Direct Sow |
| 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 6a
📆 Growing Season
192 days in Caldwell County
Growing Tips for Arugula in Caldwell County
Direct sow Arugula outdoors after April 13 in Caldwell County when soil has warmed and frost danger has passed.
Your generous 192.0-day season in Caldwell 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
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Arugula in Other Locations
Frequently Asked Questions
When should I plant Arugula in Caldwell County, MO?
Caldwell County is in Zone 6a with an average last frost of April 13. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Caldwell County, MO?
Caldwell County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 22.
Your Caldwell County Garden Planner — Free
A 24-page printable planner built for Caldwell County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.