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When to Plant Tomatillo in Gilliam County, OR

Gilliam County, Oregon Zone 7b May

This month in Gilliam County, Oregon

We've pulled the most time-sensitive tasks for Gilliam County, Oregon this May and put them front and centre. Tackle them in order.

Avg. last frost April 25
Avg. first frost October 15
Soil temp (4") 63°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
  1. Set out tomatillo seedlings

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Seed tomatillo outdoors

    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
  • Starting indoors: 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.

Gilliam County, Oregon is in USDA Zone 7b. The average last spring frost is April 25 and the first fall frost is October 15, giving you a growing season of approximately 173 days.

At an elevation of 965 feet, Gilliam County receives approximately 22.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Tomatillo during the growing season.

Gilliam County, OR (Zone 7b) Moderate season
173 days
Last Spring Frost April 25
173 growing days
First Fall Frost October 15
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Gilliam County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jul 1 – Sep 9
Recommended (50%) ✓ Fits season (26 days to spare)
Start indoors: Mar 7 Transplant: May 9 🍅 Harvest: Jul 11 – Sep 19
Safe Start (90%) ✓ Fits season (26 days to spare)
Start indoors: Mar 25 Transplant: May 27 🍅 Harvest: Jul 29 – Oct 7

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 Gilliam County

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

Soil pH

Your soil pH (5.3–6.7) overlaps with Tomatillo's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Gilliam 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 (4.5%) — Tomatillo will thrive.

How to Plant Tomatillo

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

Succession Planting Tomatillo

3
successive plantings in your 173-day season

Sow every 6.9 weeks. Last sowing by Jul 22 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.5″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,364 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 2.8" 0" ❄️ Dormant
Feb 2.8" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.8" 1.4" 3.4" 🚿 Regular watering
May 4.8" 1.4" 3.4" 🚿 Regular watering
Jun 4.8" 0.8" 4" 🚿 Regular watering
Jul 4.8" 0.3" 4.5" 🚿 Regular watering
Aug 4.8" 0.5" 4.3" 🚿 Regular watering
Sep 4.8" 0.9" 3.9" 🚿 Regular watering
Oct 4.8" 1.7" 3.1" 🚿 Regular watering
Nov 3.7" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Gilliam 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 ~997 GDD — county provides 2,378 GDD Excellent fit

Tomatillo Planting Timeline — Gilliam County, OR

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest July 11 Jul 11 – Sep 19

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December
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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 7b

📆 Growing Season

173 days in Gilliam County

Growing Tips for Tomatillo in Gilliam County

Direct sow Tomatillo outdoors after April 25 in Gilliam 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.

Gilliam County receives only 22" 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 Gilliam County, OR?

Gilliam County is in Zone 7b with an average last frost of April 25. Plan your Tomatillo planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gilliam County, OR?

Gilliam County, Oregon is in USDA Hardiness Zone 7b. The average last spring frost is April 25 and first fall frost is October 15.

🌱

Your Gilliam County Garden Planner — Free

A 24-page printable planner built for Gilliam County (Zone 7b). 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 Gilliam 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.