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When to plant Ground Cherry in Viola, IL

Viola's 181-day season only supports one Ground Cherry planting per year. Sow between May 8 and May 22 for the best chance at full maturity before October 15.

When to Plant Ground Cherry in Viola, IL

Mercer County, Illinois Zone 5b July

What to do in July

July is a pivotal month for Mercer County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 17
Avg. first frost October 15
Soil temp (4") 76°F
Watering Moderate
Pest pressure High
Daylight 14.7 hrs

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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.

Viola, Illinois is in USDA Zone 5b. The average last spring frost is April 17 and the first fall frost is October 15, giving you a growing season of approximately 181 days.

At an elevation of 777 feet, Mercer County receives approximately 37.2 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.

Viola, IL (Zone 5b) Moderate season
181 days
Last Spring Frost April 17
181 growing days
First Fall Frost October 15

Viola Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Ground Cherry Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Transplant: May 3 🍅 Harvest: Jul 12 – Sep 6
Recommended (50%) ✓ Fits season (34 days to spare)
Transplant: May 8 🍅 Harvest: Jul 17 – Sep 11
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 Viola

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

Soil pH

Your soil pH (6.3–6.7) is within Ground Cherry's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (4.0%). Annual compost additions will help Ground Cherry.

How to Plant Ground Cherry

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

Succession Planting Ground Cherry

3
successive plantings in your 181-day season

Sow every 7.4 weeks. Last sowing by Jul 27 to harvest before frost.

Ground Cherry Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 220 gal / 100 sq ft

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 1.8" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 2.5" 1.8" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Mercer 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 2,217 GDD Excellent fit

Ground Cherry Planting Timeline — Viola, IL

Ground Cherry Planting Calendar

Activity When Date Range
Transplant Outdoors May 8 May 8 – May 22
Harvest July 17 Jul 17 – Sep 11

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

181 days in Mercer County

Growing Tips for Ground Cherry in Viola

Direct sow Ground Cherry outdoors after April 17 in Mercer 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 →

When should I plant Ground Cherry in Viola, IL?

In Viola, IL, plant Ground Cherry after the last frost (around April 17) and before the first frost (around October 15). Best results when soil holds above 50°F.

What growing zone is Viola, IL for Ground Cherry?

Viola sits in USDA Zone 5b. Ground Cherry grows reliably in zones 4a through 11b, so it's a good fit here.

Can Ground Cherry grow in Viola's climate?

Yes — Ground Cherry grows well in Viola's temperate climate. Viola averages a 181-day frost-free season, with last frost around April 17 and first frost around October 15.

🌱

Your Mercer County Garden Planner — Free

A 22-page printable planner built for Mercer 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 Mercer County, IL. Local conditions may vary. Last updated: July 2026.