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When to Plant Tomatillo in Malheur County, OR

Malheur County, Oregon Zone 6b May

Your May planting checklist for Malheur County, Oregon

May is a pivotal month for Malheur County, Oregon gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 18
Avg. first frost September 29
Soil temp (4") 55°F
Watering Critical
Pest pressure Low
Daylight 14.5 hrs
  1. Outdoor sowing time: tomatillo

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

A few tasks this May that'll pay off in June
  • Transplants going out: tomatillo

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Tomatillos are a Mexican staple that produces tart, green fruits enclosed in papery husks. They are essential for salsa verde and green sauces.

Malheur County, Oregon is in USDA Zone 6b. The average last spring frost is May 18 and the first fall frost is September 29, giving you a growing season of approximately 134 days.

At an elevation of 2,676 feet, Malheur County receives approximately 17.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°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.

Malheur County, OR (Zone 6b) Short season
134 days
Last Spring Frost May 18
134 growing days
First Fall Frost September 29

Malheur County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 6 Transplant: May 15 🍅 Harvest: Jul 17 – Sep 25
Recommended (50%) ✗ May not fit
Start indoors: Mar 23 Transplant: Jun 1 🍅 Harvest: Aug 3 – Oct 12
Safe Start (90%) ✗ May not fit
Start indoors: Apr 17 Transplant: Jun 26 🍅 Harvest: Aug 28 – Nov 6

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 Malheur County

How your county's soil matches Tomatillo's growing requirements.

Soil pH

Your soil pH (5.4–6.3) is more acidic than Tomatillo prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Tomatillo.

Organic Matter

Organic matter is excellent (5.6%) — Tomatillo will thrive.

How to Plant Tomatillo

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Tomatillo

2
successive plantings in your 134-day season

Sow every 6.9 weeks. Last sowing by Jul 06 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.6″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,051 gal / 100 sq ft

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 2.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 4.8" 0.9" 3.9" 🚿 Regular watering
Jun 4.8" 0.7" 4.1" 🚿 Regular watering
Jul 4.8" 0.3" 4.5" 🚿 Regular watering
Aug 4.8" 0.3" 4.5" 🚿 Regular watering
Sep 4.8" 0.8" 4" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 2.6" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Malheur 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 needs ~1,269 GDD — county provides 2,345 GDD Excellent fit

Tomatillo Planting Timeline — Malheur County, OR

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors June 1 Jun 1 – Jun 15
Direct Sow May 25 May 25 – Jun 15
Harvest August 3 Aug 3 – Oct 12

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Direct Sow
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 · 2-3 times/week

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

134 days in Malheur County

Growing Tips for Tomatillo in Malheur County

Direct sow Tomatillo outdoors after May 18 in Malheur 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.

Malheur County receives only 18" 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

  • Fennel
  • Dill

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Tomatillo in Malheur County, OR?

Malheur County is in Zone 6b with an average last frost of May 18. Plan your Tomatillo planting based on this frost date — see the calendar above for exact timing.

What planting zone is Malheur County, OR?

Malheur County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is May 18 and first fall frost is September 29.

🌱

Your Malheur County Garden Planner — Free

A 24-page printable planner built for Malheur County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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