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When to Plant Ground Cherry in Island County, WA

Island County, Washington Zone 8b May

Your May planting checklist for Island County, Washington

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

Avg. last frost March 30
Avg. first frost November 3
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 15 hrs
Before June arrives, get these ready
  • First harvests: ground cherry

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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.

Island County, Washington is in USDA Zone 8b. The average last spring frost is March 30 and the first fall frost is November 3, giving you a growing season of approximately 218 days.

At an elevation of 9 feet, Island County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Ground Cherry during the growing season.

Island County, WA (Zone 8b) Long season
218 days
Last Spring Frost March 30
218 growing days
First Fall Frost November 3

Island County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Transplant: Apr 12 🍅 Harvest: Jun 21 – Aug 16
Recommended (50%) ✓ Fits season (71 days to spare)
Transplant: Apr 20 🍅 Harvest: Jun 29 – Aug 24
Safe Start (90%) ✓ Fits season (61 days to spare)
Transplant: May 21 🍅 Harvest: Jul 30 – Sep 24

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 Island County

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

Soil pH

Your soil pH (5.6–6.7) overlaps with Ground Cherry's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.3%) — 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 218-day season

Sow every 7.4 weeks. Last sowing by Aug 15 to harvest before frost.

Plant 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 239 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 6.8" 0" ❄️ Dormant
Feb 4.7" 0" ❄️ Dormant
Mar 4.3" 4.5" 0" ✅ Rainfall sufficient
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 2.3" 2" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 0.7" 3.6" 🚿 Regular watering
Aug 4.3" 0.8" 3.5" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 4.3" 7" 0" ✅ Rainfall sufficient
Dec 7.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in 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 ~997 GDD — county provides 2,997 GDD Excellent fit

Ground Cherry Planting Timeline — Island County, WA

Ground Cherry Planting Calendar

Activity When Date Range
Transplant Outdoors April 20 Apr 20 – May 4
Harvest June 29 Jun 29 – Aug 24

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May Transplant Outdoors
June Harvest
July Harvest
August Harvest
September
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: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

218 days in Island County

Growing Tips for Ground Cherry in Island County

Direct sow Ground Cherry outdoors after March 30 in 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 Island County, WA?

Island County is in Zone 8b with an average last frost of March 30. Plan your Ground Cherry planting based on this frost date — see the calendar above for exact timing.

What planting zone is Island County, WA?

Island County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is March 30 and first fall frost is November 3.

🌱

Your Island County Garden Planner — Free

A 24-page printable planner built for Island County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Island County, WA. 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.