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When to Plant Tomatoes in Ida County, IA

Ida County, Iowa Zone 5a May

Top priorities for Ida County, Iowa gardeners in May

A quick May briefing for Ida County, Iowa gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 25
Avg. first frost October 8
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Move tomatoes into the garden

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Put tomatoes seeds straight in the ground

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

Looking ahead to June
  • Starting indoors: tomatoes

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Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Ida County, Iowa is in USDA Zone 5a. The average last spring frost is April 25 and the first fall frost is October 8, giving you a growing season of approximately 166 days.

At an elevation of 920 feet, Ida County receives approximately 38.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Tomatoes to ensure they mature before fall.

Ida County, IA (Zone 5a) Moderate season
166 days
Last Spring Frost April 25
166 growing days
First Fall Frost October 8

Ida County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Start indoors: Feb 24 Transplant: May 5 🍅 Harvest: Jul 7 – Sep 15
Recommended (50%) ✓ Fits season (19 days to spare)
Start indoors: Feb 28 Transplant: May 9 🍅 Harvest: Jul 11 – Sep 19
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Mar 15 Transplant: May 24 🍅 Harvest: Jul 26 – Oct 4

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 Ida County

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

Soil pH

Your soil pH (6.1–6.9) is within Tomatoes's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.9%) — Tomatoes will thrive.

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

3
successive plantings in your 166-day season

Sow every 6.9 weeks. Last sowing by Jul 15 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
1.0″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 319 gal / 100 sq ft

Monthly Watering Guide for Tomatoes

Tomatoes needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Tomatoes Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 5.2" 4" 1.2" 💧 Light watering
May 5.2" 4.4" 0.8" 💧 Light watering
Jun 5.2" 4.2" 1" 💧 Light watering
Jul 5.2" 3.9" 1.3" 💧 Light watering
Aug 5.2" 3.9" 1.3" 💧 Light watering
Sep 5.2" 3.7" 1.5" 💧 Light watering
Oct 5.2" 3.4" 1.8" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ida County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Tomatoes 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.

Tomatoes needs ~725 GDD — county provides 1,660 GDD Excellent fit

Tomatoes Planting Timeline — Ida County, IA

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest July 11 Jul 11 – Sep 19

Plant 0.5" deep · 24" apart · Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · Only during dry spells

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

166 days in Ida County

Growing Tips for Tomatoes in Ida County

Direct sow Tomatoes outdoors after April 25 in Ida County when soil has warmed and frost danger has passed.

Common pests for Tomatoes 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. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35°F, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Ida County, IA?

Ida County is in Zone 5a with an average last frost of April 25. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ida County, IA?

Ida County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 25 and first fall frost is October 8.

🌱

Your Ida County Garden Planner — Free

A 24-page printable planner built for Ida County (Zone 5a). 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 Ida County, IA. 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.