When to Plant Arugula in Delaware County, PA
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.
Delaware County, Pennsylvania is in USDA Zone 7a. The average last spring frost is April 16 and the first fall frost is October 24, giving you a growing season of approximately 191 days.
At an elevation of 1,094 feet, Delaware County receives approximately 38.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Arugula during the growing season.
Delaware County Soil Profile
Soil Type
Silt Loam
Soil pH
5-6.2
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 Delaware County
How your county's soil matches Arugula's growing requirements.
Soil pH
Your soil pH (5.0–6.2) is more acidic than Arugula prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Delaware County is excellent for Arugula — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). 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 04 to harvest before frost.
For a dedicated fall crop, sow by Aug 15.
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 | — | 2.9" | 0" | ❄️ Dormant |
| Feb | — | 2.3" | 0" | ❄️ Dormant |
| Mar | — | 3.1" | 0" | ❄️ Dormant |
| Apr | 2.6" | 3.6" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 3.3" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 3.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 4.2" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 3.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.7" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 3.4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 2.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Delaware 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 — Delaware County, PA
Arugula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 12 | Mar 12 – Mar 26 |
| Transplant Outdoors | April 16 | Apr 16 – Apr 30 |
| Direct Sow | April 2 | Apr 2 – Apr 23 |
| Harvest | May 21 | May 21 – Jul 23 |
| Fall Sowing | August 15 | Aug 15 – Aug 29 |
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: too_acidic
🗺️ USDA Zone
Zone 7a
📆 Growing Season
191 days in Delaware County
Growing Tips for Arugula in Delaware County
Direct sow Arugula outdoors after April 16 in Delaware County when soil has warmed and frost danger has passed.
Your generous 191.0-day season in Delaware 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 Delaware County, PA?
Delaware County is in Zone 7a with an average last frost of April 16. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Delaware County, PA?
Delaware County, Pennsylvania is in USDA Hardiness Zone 7a. The average last spring frost is April 16 and first fall frost is October 24.
Plan Your Garden with Confidence
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