When to Plant Tomatillo in Imperial County, CA
May in Imperial County, California — your action list
Here's what deserves your attention in Imperial County, California this month. Everything below is tailored to Zone 10a and timed around your local frost dates.
-
Pick tomatillo
If you can't use it all right away, check the food-preservation section of your planner.
Coming up in June — start thinking about
- 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.
Imperial County, California is in USDA Zone 10a. The average last spring frost is January 29 and the first fall frost is December 20, giving you a growing season of approximately 325 days.
At an elevation of 181 feet, Imperial County receives approximately 16.8 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.
Imperial County Soil Profile
Soil Type
Loam
Soil pH
5.7-7.3
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 Imperial County
How your county's soil matches Tomatillo's growing requirements.
Soil pH
Your soil pH (5.7–7.3) overlaps with Tomatillo's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Imperial County is excellent for Tomatillo — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Tomatillo.
How to Plant Tomatillo
Succession Planting Tomatillo
Sow every 6.9 weeks. Last sowing by Sep 26 to harvest before frost.
Plant Water Budget
Water stress score is 10/10 — 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 | 4.8" | 3" | 1.8" | 💧 Light watering |
| Feb | 4.8" | 3.3" | 1.5" | 💧 Light watering |
| Mar | 4.8" | 3.1" | 1.7" | 💧 Light watering |
| Apr | 4.8" | 1.4" | 3.4" | 🚿 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" | 0.6" | 4.2" | 🚿 Regular watering |
| Nov | 4.8" | 1.5" | 3.3" | 🚿 Regular watering |
| Dec | 4.8" | 3.3" | 1.5" | 💧 Light watering |
Water needs are for active growing months only (Jan–Dec in Imperial 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 — Imperial County, CA
Tomatillo Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 18 | Dec 18 – Jan 1 |
| Transplant Outdoors | February 5 | Feb 5 – Feb 19 |
| Direct Sow | January 29 | Jan 29 – Feb 19 |
| Harvest | April 9 | Apr 9 – Jun 18 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Direct Sow |
| 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: acceptable
🗺️ USDA Zone
Zone 10a
📆 Growing Season
325 days in Imperial County
Growing Tips for Tomatillo in Imperial County
Direct sow Tomatillo outdoors after January 29 in Imperial 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.
Imperial County receives only 17" 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 Imperial County, CA?
Imperial County is in Zone 10a with an average last frost of January 29. Plan your Tomatillo planting based on this frost date — see the calendar above for exact timing.
What planting zone is Imperial County, CA?
Imperial County, California is in USDA Hardiness Zone 10a. The average last spring frost is January 29 and first fall frost is December 20.
Your Imperial County Garden Planner — Free
A 24-page printable planner built for Imperial County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.