When to Plant Ground Cherry in Napa County, CA
Ground cherries produce small, sweet, tropical-tasting berries enclosed in papery husks. They are related to tomatillos and cape gooseberries and self-sow readily.
Napa County, California is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.
At an elevation of 449 feet, Napa County receives approximately 35 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Ground Cherry during the growing season.
Napa County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.5
Drainage
Well Drained
Plant Planting Risk Windows
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 Napa County
How your county's soil matches Ground Cherry's growing requirements.
Soil pH
Your soil pH (6.7–7.5) is within Ground Cherry's preferred range (6.0–7.5).
Soil Texture
The loam soil in Napa County is excellent for Ground Cherry — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Ground Cherry.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Ground Cherry.
How to Plant Ground Cherry
Succession Planting Ground Cherry
Sow every 7.4 weeks. Last sowing by Sep 07 to harvest before frost.
Plant Water Budget
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 | — | 7.5" | 0" | ❄️ Dormant |
| Feb | 4.3" | 7.8" | 0" | ✅ Rainfall sufficient |
| Mar | 4.3" | 5.8" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 2.3" | 2" | 💧 Light watering |
| May | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Jun | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Oct | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Nov | 4.3" | 3.3" | 1" | 💧 Light watering |
| Dec | — | 5.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Napa 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 Planting Timeline — Napa County, CA
Ground Cherry Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | March 12 | Mar 12 – Mar 26 |
| Harvest | May 21 | May 21 – Jul 16 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Transplant Outdoors |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
65–80 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 9a
📆 Growing Season
273 days in Napa County
Growing Tips for Ground Cherry in Napa County
Direct sow Ground Cherry outdoors after February 26 in Napa 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
Check more plant combinations with our Companion Planting Checker →
Ground Cherry in Other Locations
Frequently Asked Questions
When should I plant Ground Cherry in Napa County, CA?
Napa County is in Zone 9a with an average last frost of February 26. Plan your Ground Cherry planting based on this frost date — see the calendar above for exact timing.
What planting zone is Napa County, CA?
Napa County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is November 26.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Napa County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.