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When to Plant Tomatillo in Adair County, OK

Adair County, Oklahoma Zone 7b May

What to do in May

Each item below is timed to Adair County, Oklahoma's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 7
Avg. first frost October 27
Soil temp (4") 66°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Fire up the seed-starting tray: tomatillo

    You're about 24 weeks out from your last frost — the perfect window to get these germinating indoors.

A few tasks this May that'll pay off in June
  • First harvests: 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.

Adair County, Oklahoma is in USDA Zone 7b. The average last spring frost is April 7 and the first fall frost is October 27, giving you a growing season of approximately 203 days.

At an elevation of 486 feet, Adair County receives approximately 33.9 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Tomatillo during the growing season.

Adair County, OK (Zone 7b) Long season
203 days
Last Spring Frost April 7
203 growing days
First Fall Frost October 27

Adair County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (62 days to spare)
Start indoors: Feb 7 Transplant: Apr 11 🍅 Harvest: Jun 13 – Aug 22
Recommended (50%) ✓ Fits season (56 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jun 23 – Sep 1
Safe Start (90%) ✓ Fits season (62 days to spare)
Start indoors: Mar 7 Transplant: May 9 🍅 Harvest: Jul 11 – Sep 19

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 Adair County

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

Soil pH

Your soil pH (6.7–7.1) overlaps with Tomatillo's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Tomatillo will thrive.

How to Plant Tomatillo

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

Succession Planting Tomatillo

3
successive plantings in your 203-day season

Sow every 6.9 weeks. Last sowing by Aug 03 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 720 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 1" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.8" 4.2" 0.6" 💧 Light watering
May 4.8" 4.5" 0.3" 💧 Light watering
Jun 4.8" 5.5" 0" ✅ Rainfall sufficient
Jul 4.8" 4.1" 0.7" 💧 Light watering
Aug 4.8" 3.6" 1.2" 💧 Light watering
Sep 4.8" 3.1" 1.7" 💧 Light watering
Oct 4.8" 2.4" 2.4" 🚿 Regular watering
Nov 1.2" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Adair 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 ~1,432 GDD — county provides 4,009 GDD Excellent fit

Tomatillo Planting Timeline — Adair County, OK

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 14 Apr 14 – May 5
Harvest June 23 Jun 23 – Sep 1

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September Harvest
October
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: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

203 days in Adair County

Growing Tips for Tomatillo in Adair County

Direct sow Tomatillo outdoors after April 07 in Adair 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.

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 Adair County, OK?

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

What planting zone is Adair County, OK?

Adair County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is April 7 and first fall frost is October 27.

🌱

Your Adair County Garden Planner — Free

A 24-page printable planner built for Adair 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 Adair County, OK. 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.