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When to Plant Eggplant in Hunterdon County, NJ

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.

Hunterdon County, New Jersey is in USDA Zone 6b. The average last spring frost is April 12 and the first fall frost is October 29, giving you a growing season of approximately 200 days.

At an elevation of 534 feet, Hunterdon County receives approximately 46.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, providing good warmth for Eggplant during the growing season.

Hunterdon County, NJ (Zone 6b) Long season
200 days
Last Spring Frost April 12
200 growing days
First Fall Frost October 29

Hunterdon County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Start indoors: Jan 25 Transplant: Apr 19 🍅 Harvest: Jun 28 – Aug 30
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Feb 1 Transplant: Apr 26 🍅 Harvest: Jul 5 – Sep 6
Safe Start (90%) ✓ Fits season (48 days to spare)
Start indoors: Feb 20 Transplant: May 15 🍅 Harvest: Jul 24 – Sep 25

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 Hunterdon County

How your county's soil matches Eggplant's growing requirements.

Soil pH

Your soil pH (5.2โ€“6.3) overlaps with Eggplant's range (5.5โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Hunterdon County is excellent for Eggplant โ€” 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

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Eggplant

3
successive plantings in your 200-day season

Sow every 7.4 weeks. Last sowing by Aug 05 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 209 gal / 100 sq ft

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 โ€” 3.7" 0" โ„๏ธ Dormant
Feb โ€” 2.7" 0" โ„๏ธ Dormant
Mar โ€” 4.1" 0" โ„๏ธ Dormant
Apr 4.8" 3.8" 1" ๐Ÿ’ง Light watering
May 4.8" 3.7" 1.1" ๐Ÿ’ง Light watering
Jun 4.8" 4.1" 0.7" ๐Ÿ’ง Light watering
Jul 4.8" 5.1" 0" โœ… Rainfall sufficient
Aug 4.8" 4.1" 0.7" ๐Ÿ’ง Light watering
Sep 4.8" 4.1" 0.7" ๐Ÿ’ง Light watering
Oct 4.8" 4.1" 0.7" ๐Ÿ’ง Light watering
Nov โ€” 3.7" 0" โ„๏ธ Dormant
Dec โ€” 3.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Hunterdon County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 needs ~1,312 GDD — county provides 3,500 GDD Excellent fit

Eggplant Planting Timeline โ€” Hunterdon County, NJ

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 1 Feb 1 โ€“ Feb 15
Transplant Outdoors April 26 Apr 26 โ€“ May 10
Direct Sow April 19 Apr 19 โ€“ May 10
Harvest July 5 Jul 5 โ€“ Sep 6

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March โ€”
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

65โ€“85 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

200 days in Hunterdon County

Growing Tips for Eggplant in Hunterdon County

Direct sow Eggplant outdoors after April 12 in Hunterdon 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

  • Fennel
  • Kohlrabi

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Eggplant in Hunterdon County, NJ?

Hunterdon County is in Zone 6b with an average last frost of April 12. Plan your Eggplant planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Hunterdon County, NJ?

Hunterdon County, New Jersey is in USDA Hardiness Zone 6b. The average last spring frost is April 12 and first fall frost is October 29.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Hunterdon County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Hunterdon County, NJ. Local conditions may vary. Last updated: April 2026.