When to Plant Tomatillo in San Joaquin County, CA
Top priorities for San Joaquin County, California gardeners in May
Welcome to May in Zone 9b. These are the moves that will have the biggest impact on your growing season.
-
Start harvesting tomatillo
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
Before June arrives, get these ready
- First harvests: tomatillo
Tomatillos are a Mexican staple that produces tart, green fruits enclosed in papery husks. They are essential for salsa verde and green sauces.
San Joaquin County, California is in USDA Zone 9b. The average last spring frost is February 4 and the first fall frost is December 6, giving you a growing season of approximately 305 days.
At an elevation of 220 feet, San Joaquin County receives approximately 15 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Tomatillo during the growing season. With low rainfall, drip irrigation is essential for growing Tomatillo successfully. Mulch heavily to conserve soil moisture.
San Joaquin County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.8
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 San Joaquin County
How your county's soil matches Tomatillo's growing requirements.
Soil pH
Your soil pH (6.4–7.8) is more alkaline than Tomatillo prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in San Joaquin County is excellent for Tomatillo — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Tomatillo.
How to Plant Tomatillo
Succession Planting Tomatillo
Sow every 6.9 weeks. Last sowing by Sep 12 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Tomatillo
Tomatillo needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.
| Month | Tomatillo Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.9" | 0" | ❄️ Dormant |
| Feb | 4.8" | 3.1" | 1.7" | 💧 Light watering |
| Mar | 4.8" | 2.6" | 2.2" | 💧 Light watering |
| Apr | 4.8" | 1.2" | 3.6" | 🚿 Regular watering |
| May | 4.8" | 0.4" | 4.4" | 🚿 Regular watering |
| Jun | 4.8" | 0.1" | 4.7" | 🚿 Regular watering |
| Jul | 4.8" | 0" | 4.8" | 🚿 Regular watering |
| Aug | 4.8" | 0" | 4.8" | 🚿 Regular watering |
| Sep | 4.8" | 0.2" | 4.6" | 🚿 Regular watering |
| Oct | 4.8" | 0.7" | 4.1" | 🚿 Regular watering |
| Nov | 4.8" | 1.3" | 3.5" | 🚿 Regular watering |
| Dec | 4.8" | 2.6" | 2.2" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in San Joaquin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Tomatillo 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.
Tomatillo Planting Timeline — San Joaquin County, CA
Tomatillo Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 24 | Dec 24 – Jan 7 |
| Transplant Outdoors | February 11 | Feb 11 – Feb 25 |
| Direct Sow | February 4 | Feb 4 – Feb 25 |
| Harvest | April 15 | Apr 15 – Jun 24 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Transplant Outdoors Direct Sow |
| March | — |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | Start Indoors |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · 2-3 times/week
📅 Days to Maturity
60–85 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 9b
📆 Growing Season
305 days in San Joaquin County
Growing Tips for Tomatillo in San Joaquin County
Direct sow Tomatillo outdoors after February 04 in San Joaquin County when soil has warmed and frost danger has passed.
Common pests for Tomatillo in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
San Joaquin County receives only 15" of rain annually. Tomatillo needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Start seeds indoors 6-8 weeks before last frost. Plant at least two plants for cross-pollination. Harvest when fruits fill the husk and it begins to split.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Tomatillo in Other Locations
Frequently Asked Questions
When should I plant Tomatillo in San Joaquin County, CA?
San Joaquin County is in Zone 9b with an average last frost of February 4. Plan your Tomatillo planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Joaquin County, CA?
San Joaquin County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 4 and first fall frost is December 6.
Your San Joaquin County Garden Planner — Free
A 24-page printable planner built for San Joaquin County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.