When to Plant Eggplant in Union County, PA
May to-do list for Union County, Pennsylvania
Here's what deserves your attention in Union County, Pennsylvania this month. Everything below is tailored to Zone 6b and timed around your local frost dates.
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Transplant eggplant outside
Your last frost (April 27) has passed. These warm-season crops can handle outdoor soil now.
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Direct-sow eggplant
Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.
Eggplant is a heat-loving solanaceous crop that produces glossy fruits in purple, white, or striped varieties. It requires long, warm growing seasons for best production.
Union County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 27 and the first fall frost is October 22, giving you a growing season of approximately 178 days.
At an elevation of 250 feet, Union County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Eggplant during the growing season.
Union County Soil Profile
Soil Type
Silt Loam
Soil pH
5.1-6.2
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 Union County
How your county's soil matches Eggplant's growing requirements.
Soil pH
Your soil pH (5.1–6.2) overlaps with Eggplant's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Union County is excellent for Eggplant — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.7%). Annual compost additions will help Eggplant.
How to Plant Eggplant
Succession Planting Eggplant
Sow every 7.4 weeks. Last sowing by Jul 29 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Eggplant
Eggplant needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.
| Month | Eggplant Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.9" | 0" | ❄️ Dormant |
| Feb | — | 2.6" | 0" | ❄️ Dormant |
| Mar | — | 3.2" | 0" | ❄️ Dormant |
| Apr | 4.8" | 3.5" | 1.3" | 💧 Light watering |
| May | 4.8" | 4" | 0.8" | 💧 Light watering |
| Jun | 4.8" | 3.8" | 1" | 💧 Light watering |
| Jul | 4.8" | 4" | 0.8" | 💧 Light watering |
| Aug | 4.8" | 3" | 1.8" | 💧 Light watering |
| Sep | 4.8" | 3.3" | 1.5" | 💧 Light watering |
| Oct | 4.8" | 2.9" | 1.9" | 💧 Light watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2.9" | 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.
Eggplant 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.
Eggplant Planting Timeline — Union County, PA
Eggplant Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 16 | Feb 16 – Mar 2 |
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Direct Sow | May 4 | May 4 – May 25 |
| Harvest | July 20 | Jul 20 – Sep 21 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · Only during dry spells
📅 Days to Maturity
65–85 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
178 days in Union County
Growing Tips for Eggplant in Union County
Direct sow Eggplant outdoors after April 27 in Union County when soil has warmed and frost danger has passed.
Common pests for Eggplant in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 8-10 weeks before last frost. Transplant only after nighttime temperatures stay above 55F. Mulch to retain moisture and warmth around roots.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Eggplant in Other Locations
Frequently Asked Questions
When should I plant Eggplant in Union County, PA?
Union County is in Zone 6b with an average last frost of April 27. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, PA?
Union County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 27 and first fall frost is October 22.
Your Union County Garden Planner — Free
A 24-page printable planner built for Union County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.