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When to Plant Mustard Greens in Mercer County, NJ

Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.

Mercer County, New Jersey is in USDA Zone 7a. 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 4 feet, Mercer County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, providing good warmth for Mustard Greens during the growing season.

Mercer County, NJ (Zone 7a) Long season
200 days
Last Spring Frost April 12
200 growing days
First Fall Frost October 29

Mercer County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (98 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: May 10 – Jul 12
Recommended (50%) ✓ Fits season (102 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: May 17 – Jul 19
Safe Start (90%) ✓ Fits season (97 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jun 5 – Aug 7

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

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 79 gal / 100 sq ft
Mustard Greens needs ~700 GDD — county provides 3,500 GDD Excellent fit

Mustard Greens Planting Timeline โ€” Mercer County, NJ

Mustard Greens Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 โ€“ Mar 22
Transplant Outdoors April 12 Apr 12 โ€“ Apr 26
Direct Sow March 29 Mar 29 โ€“ Apr 19
Fall Sowing August 20 Aug 20 โ€“ Sep 3
Harvest May 17 May 17 โ€“ Jul 19

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

30โ€“50 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7a

Growing Season

200 days

Growing Tips for Mercer County

Direct sow in early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

When should I plant Mustard Greens in Mercer County, NJ?

Mercer County is in Zone 7a with an average last frost of April 12. Plan your Mustard Greens planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Mercer County, NJ?

Mercer County, New Jersey is in USDA Hardiness Zone 7a. 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 Mercer County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

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