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When to Plant Ground Cherry in Rock Island County, IL

Rock Island County, Illinois Zone 5b May

What to do in May

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

Avg. last frost April 15
Avg. first frost October 19
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Plant out ground cherry

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

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Ground cherries produce small, sweet, tropical-tasting berries enclosed in papery husks. They are related to tomatillos and cape gooseberries and self-sow readily.

Rock Island County, Illinois is in USDA Zone 5b. The average last spring frost is April 15 and the first fall frost is October 19, giving you a growing season of approximately 187 days.

At an elevation of 1,172 feet, Rock Island County receives approximately 35.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Ground Cherry to ensure they mature before fall.

Rock Island County, IL (Zone 5b) Moderate season
187 days
Last Spring Frost April 15
187 growing days
First Fall Frost October 19

Rock Island County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Transplant: May 1 🍅 Harvest: Jul 10 – Sep 4
Recommended (50%) ✓ Fits season (40 days to spare)
Transplant: May 6 🍅 Harvest: Jul 15 – Sep 9
Safe Start (90%) ✓ Fits season (38 days to spare)
Transplant: May 24 🍅 Harvest: Aug 2 – Sep 27

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 Rock Island County

How your county's soil matches Ground Cherry's growing requirements.

Soil pH

Your soil pH (6.3–6.9) is within Ground Cherry's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Rock Island County is excellent for Ground Cherry — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.7%) — Ground Cherry will thrive.

How to Plant Ground Cherry

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Ground Cherry

3
successive plantings in your 187-day season

Sow every 7.4 weeks. Last sowing by Jul 31 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 391 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Ground Cherry

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

Month Ground Cherry Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 3.5" 0.8" 💧 Light watering
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 2.7" 1.6" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

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

Ground Cherry 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.

Ground Cherry needs ~888 GDD — county provides 2,290 GDD Excellent fit

Ground Cherry Planting Timeline — Rock Island County, IL

Ground Cherry Planting Calendar

Activity When Date Range
Transplant Outdoors May 6 May 6 – May 20
Harvest July 15 Jul 15 – Sep 9

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

65–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

187 days in Rock Island County

Growing Tips for Ground Cherry in Rock Island County

Direct sow Ground Cherry outdoors after April 15 in Rock Island County when soil has warmed and frost danger has passed.

Common pests for Ground Cherry 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 6-8 weeks before last frost. Let fruits fall to the ground naturally when ripe inside their husks. The husk turns brown and papery when the fruit is ready.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Ground Cherry in Rock Island County, IL?

Rock Island County is in Zone 5b with an average last frost of April 15. Plan your Ground Cherry planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rock Island County, IL?

Rock Island County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 15 and first fall frost is October 19.

🌱

Your Rock Island County Garden Planner — Free

A 24-page printable planner built for Rock Island County (Zone 5b). 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 Rock Island 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.