When to Plant Tomatillo in Grande Prairie, AB
Tomatillos are a Mexican staple that produces tart, green fruits enclosed in papery husks. They are essential for salsa verde and green sauces.
Grande Prairie, Alberta is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is October 9, giving you a growing season of approximately 140 days.
At an elevation of 2,194 feet, Grande Prairie receives approximately 19 inches of rainfall annually with predominantly dark brown chernozem soil. Summer highs average 75°F, so choose short-season varieties of Tomatillo to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Tomatillo successfully. Mulch heavily to conserve soil moisture.
Grande Prairie Soil Profile
Soil Type
Dark Brown Chernozem
Soil pH
6.0-7.0
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.
How to Plant Tomatillo
Plant Water Budget
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 | — | 0.7" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.1" | 0" | ❄️ Dormant |
| Apr | — | 1.9" | 0" | ❄️ Dormant |
| May | 4.8" | 2.4" | 2.4" | 🚿 Regular watering |
| Jun | 4.8" | 2.5" | 2.3" | 💧 Light watering |
| Jul | 4.8" | 2.2" | 2.6" | 🚿 Regular watering |
| Aug | 4.8" | 2.1" | 2.7" | 🚿 Regular watering |
| Sep | 4.8" | 1.6" | 3.2" | 🚿 Regular watering |
| Oct | 4.8" | 1.6" | 3.2" | 🚿 Regular watering |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Grande Prairie). 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 — Grande Prairie, AB
Tomatillo Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 20 | Mar 20 – Apr 3 |
| Transplant Outdoors | June 12 | Jun 12 – Jun 26 |
| Direct Sow | June 5 | Jun 5 – Jun 26 |
| Harvest | August 14 | Aug 14 – Oct 23 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | — |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · 1-2 times/week
📅 Days to Maturity
60–85 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 4a
📆 Growing Season
140 days in Grande Prairie
Growing Tips for Tomatillo in Grande Prairie
Common pests for Tomatillo in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
Grande Prairie receives only 19" 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 Grande Prairie, AB?
Grande Prairie is in Zone 4a with an average last frost of May 22. Plan your Tomatillo planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grande Prairie, AB?
Grande Prairie, Alberta is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is October 9.
Your Grande Prairie Garden Planner — Free
A 24-page printable planner built for Grande Prairie (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.