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When to Plant New Zealand Spinach in Jefferson County, IL

Jefferson County, Illinois Zone 6b May

Top priorities for Jefferson County, Illinois gardeners in May

Your garden in Jefferson County, Illinois is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 9
Avg. first frost October 20
Soil temp (4") 65°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
June prep starts now
  • Starting indoors: new zealand spinach
  • First harvests: new zealand spinach

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New Zealand spinach is a heat-tolerant ground-cover plant with thick, triangular leaves that taste similar to true spinach. It thrives in hot weather when regular spinach bolts.

Jefferson County, Illinois is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 20, giving you a growing season of approximately 194 days.

At an elevation of 509 feet, Jefferson County receives approximately 34 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for New Zealand Spinach during the growing season.

Jefferson County, IL (Zone 6b) Moderate season
194 days
Last Spring Frost April 9
194 growing days
First Fall Frost October 20

Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (94 days to spare)
Start indoors: Feb 7 Transplant: Apr 18 🍅 Harvest: Jun 13 – Jul 11
Recommended (50%) ✓ Fits season (96 days to spare)
Start indoors: Feb 12 Transplant: Apr 23 🍅 Harvest: Jun 18 – Jul 16
Safe Start (90%) ✓ Fits season (99 days to spare)
Start indoors: Feb 22 Transplant: May 3 🍅 Harvest: Jun 28 – Jul 26

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 Jefferson County

How your county's soil matches New Zealand Spinach's growing requirements.

Soil pH

Your soil pH (6.1–7.1) is within New Zealand Spinach's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Jefferson County is excellent for New Zealand Spinach — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.2%) — New Zealand Spinach will thrive.

How to Plant New Zealand Spinach

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Succession Planting New Zealand Spinach

4
successive plantings in your 194-day season

Sow every 6.3 weeks. Last sowing by Aug 11 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 547 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for New Zealand Spinach

New Zealand Spinach needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month New Zealand Spinach Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 3" 1.3" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

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

New Zealand Spinach 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.

New Zealand Spinach needs ~1,000 GDD — county provides 3,104 GDD Excellent fit

New Zealand Spinach Planting Timeline — Jefferson County, IL

New Zealand Spinach Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 – Feb 26
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 16 Apr 16 – May 7
Harvest June 18 Jun 18 – Jul 16

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

55–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

194 days in Jefferson County

Growing Tips for New Zealand Spinach in Jefferson County

Direct sow New Zealand Spinach outdoors after April 09 in Jefferson County when soil has warmed and frost danger has passed.

General growing tips

Soak seeds overnight before planting. Direct sow after last frost. Pinch growing tips regularly to encourage bushy growth and tender new leaves.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant New Zealand Spinach in Jefferson County, IL?

Jefferson County is in Zone 6b with an average last frost of April 9. Plan your New Zealand Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, IL?

Jefferson County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 20.

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Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson 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.

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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 Jefferson County, IL. Local conditions may vary. Last updated: May 2026.

Sources & credits

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