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When to plant Tomatillo in Ada County, ID

Plant Tomatillo in Ada County, when soil hits 50°F — usually April 30. Continue planting through May 21 for the spring crop.

When to Plant Tomatillo in Ada County, ID

Ada County, Idaho Zone 7a July

Top priorities for Ada County, Idaho gardeners in July

Here's what deserves your attention in Ada County, Idaho this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost April 23
Avg. first frost October 16
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.9 hrs
  1. Bring in the tomatillo

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Get ahead of August
  • 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.

Ada County, Idaho is in USDA Zone 7a. The average last spring frost is April 23 and the first fall frost is October 16, giving you a growing season of approximately 176 days.

At an elevation of 4,372 feet, Ada County receives approximately 19.8 inches of rainfall annually with predominantly 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.

Ada County, ID (Zone 7a) Moderate season
176 days
Last Spring Frost April 23
176 growing days
First Fall Frost October 16

Ada County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Tomatillo Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jul 1 – Sep 9
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Mar 5 Transplant: May 7 🍅 Harvest: Jul 9 – Sep 17
Safe Start (90%) ✓ Fits season (27 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 Ada County

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

Soil pH

Your soil pH (6.4–7.7) is more alkaline than Tomatillo prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Tomatillo.

How to Plant Tomatillo

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

Succession Planting Tomatillo

3
successive plantings in your 176-day season

Sow every 6.9 weeks. Last sowing by Jul 23 to harvest before frost.

Tomatillo Water Budget

Plant needs
1.1″/week
Rainfall provides
0.5″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,179 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 4.8" 2" 2.8" 🚿 Regular watering
May 4.8" 2.4" 2.4" 🚿 Regular watering
Jun 4.8" 1.4" 3.4" 🚿 Regular watering
Jul 4.8" 1.8" 3" 🚿 Regular watering
Aug 4.8" 2.4" 2.4" 🚿 Regular watering
Sep 4.8" 1.5" 3.3" 🚿 Regular watering
Oct 4.8" 1.8" 3" 🚿 Regular watering
Nov 1.3" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ada 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 3,080 GDD Excellent fit

Tomatillo Planting Timeline — Ada County, ID

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors May 7 May 7 – May 21
Direct Sow April 30 Apr 30 – May 21
Harvest July 9 Jul 9 – Sep 17

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7a

📆 Growing Season

176 days in Ada County

Growing Tips for Tomatillo in Ada County

Direct sow Tomatillo outdoors after April 23 in Ada 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.

Ada County receives only 20" 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 Ada County, ID?

Ada County is in Zone 7a with an average last frost of April 23. Plan your Tomatillo planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ada County, ID?

Ada County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is April 23 and first fall frost is October 16.

When should I plant Tomatillo in Ada County, ID?

In Ada County, ID, plant Tomatillo after the last frost (around April 23) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Ada County, ID for Tomatillo?

Ada County sits in USDA Zone 7a. Tomatillo grows reliably in zones 4a through 11b, so it's a good fit here.

Can Tomatillo grow in Ada County's climate?

Yes — Tomatillo grows well in Ada County's temperate climate. Ada County averages a 176-day frost-free season, with last frost around April 23 and first frost around October 16.

🌱

Your Ada County Garden Planner — Free

A 22-page printable planner built for Ada County (Zone 7a). 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 Ada County, ID. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.