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When to Plant Calendula in Middlesex County, NJ

Middlesex County, New Jersey Zone 7a June

What to do in June

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost March 29
Avg. first frost November 12
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Start harvesting calendula

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Get ahead of July
  • First harvests: calendula

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Calendula (Calendula officinalis) is a cheerful, edible-flowered cool-season annual valued by herbalists, chefs, and gardeners alike. Its golden-orange petals are used in salves, teas, and as a saffron substitute. Hardy enough to tolerate light frosts, it blooms prolifically in spring and fall, taking a pause during the hottest weeks of summer.

Middlesex County, New Jersey is in USDA Zone 7a. The average last spring frost is March 29 and the first fall frost is November 12, giving you a growing season of approximately 228 days.

At an elevation of 947 feet, Middlesex County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94°F, providing good warmth for Calendula during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Middlesex County, NJ (Zone 7a) Long season
228 days
Last Spring Frost March 29
228 growing days
First Fall Frost November 12

Middlesex County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.6

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Start indoors: Feb 11 Transplant: Mar 25 🌸 Bloom: May 13 – Aug 26
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Feb 15 Transplant: Mar 29 🌸 Bloom: May 17 – Aug 30
Safe Start (90%) ✓ Fits season (83 days to spare)
Start indoors: Feb 26 Transplant: Apr 9 🌸 Bloom: May 28 – Sep 10

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 Middlesex County

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

Soil pH

Your soil pH (5.0–6.6) overlaps with Calendula's range (5.5–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Middlesex County is excellent for Calendula — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Calendula.

How to Plant Calendula

0.3"
Planting Depth
9"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Calendula

5
successive plantings in your 228-day season

Sow every 5.7 weeks. Last sowing by Sep 03 to harvest before frost.

For a dedicated fall crop, sow by Sep 17.

Calendula Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Calendula

Calendula needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Calendula Needs Rainfall You Supplement Action
Jan 3.3" 0" ❄️ Dormant
Feb 3.1" 0" ❄️ Dormant
Mar 2.2" 3.6" 0" ✅ Rainfall sufficient
Apr 2.2" 4.2" 0" ✅ Rainfall sufficient
May 2.2" 4.8" 0" ✅ Rainfall sufficient
Jun 2.2" 4.9" 0" ✅ Rainfall sufficient
Jul 2.2" 4" 0" ✅ Rainfall sufficient
Aug 2.2" 4.3" 0" ✅ Rainfall sufficient
Sep 2.2" 3.4" 0" ✅ Rainfall sufficient
Oct 2.2" 3.7" 0" ✅ Rainfall sufficient
Nov 2.2" 3.2" 0" ✅ Rainfall sufficient
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Middlesex County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Calendula 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.

Calendula needs ~1,230 GDD — county provides 4,674 GDD Excellent fit

Calendula Planting Timeline — Middlesex County, NJ

Calendula Planting Calendar

Activity When Date Range
Start Indoors February 15 Feb 15 – Mar 1
Transplant Outdoors March 29 Mar 29 – Apr 12
Direct Sow February 22 Feb 22 – Mar 15
Bloom May 17 May 17 – Aug 30
Fall Sowing September 17 Sep 17 – Oct 1

Plant 0.3" deep · 9" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

228 days in Middlesex County

Growing Tips for Calendula in Middlesex County

Direct sow Calendula outdoors after March 29 in Middlesex County when soil has warmed and frost danger has passed.

Common pests for Calendula in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct-sow in early spring as soon as soil can be worked — seeds germinate in cool soil (50-65°F). In zones 7+, also sow in fall for winter/spring bloom. Deadhead consistently to extend bloom. Plants self-seed readily; save a few spent heads and allow them to drop. Harvest petals when flowers are fully open for best flavor and medicinal value.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Calendula in Middlesex County, NJ?

Middlesex County is in Zone 7a with an average last frost of March 29. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Middlesex County, NJ?

Middlesex County, New Jersey is in USDA Hardiness Zone 7a. The average last spring frost is March 29 and first fall frost is November 12.

🌱

Your Middlesex County Garden Planner — Free

A 22-page printable planner built for Middlesex County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Middlesex County, NJ. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.