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When to plant Gladiolus in Tama County County,

Plant Gladiolus in Tama County County, when soil hits 50°F — usually May 5. Continue planting through May 26 for the spring crop.

When to Plant Gladiolus in Tama County, IA

Tama County, Iowa Zone 5a June

This month in Tama County, Iowa

Your Tama County, Iowa garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 28
Avg. first frost October 8
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
July will be here before you know it — start on
  • First harvests: gladiolus

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Gladiolus (Gladiolus spp.) produce tall, stately spikes of trumpet-shaped blooms in a rich array of colors, making them one of the most popular cut flowers in the world. Each spike carries 12–20 florets that open in succession from bottom to top over 7–10 days. By planting corms every two weeks from last frost through early summer, gardeners create a continuous succession of fresh blooms from midsummer through fall. Corms multiply each season — a single planting becomes a growing collection over the years. Ideal for back-of- border planting, cutting gardens, and mixed summer containers.

Tama County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 8, giving you a growing season of approximately 163 days.

At an elevation of 1,268 feet, Tama County receives approximately 38.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Gladiolus during the growing season.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Tama County, IA (Zone 5a) Moderate season
163 days
Last Spring Frost April 28
163 growing days
First Fall Frost October 8

Tama County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Gladiolus Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 29 🌸 Bloom: Jul 22 – Oct 14
Recommended (50%) ✗ May not fit
Transplant: May 5 🌸 Bloom: Jul 28 – Oct 20
Safe Start (90%) ✗ May not fit
Transplant: May 19 🌸 Bloom: Aug 11 – Nov 3

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 Tama County

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

Soil pH

Your soil pH (5.8–6.9) overlaps with Gladiolus's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Gladiolus.

Organic Matter

Organic matter is excellent (5.1%) — Gladiolus will thrive.

How to Plant Gladiolus

5"
Planting Depth
5"
Between Plants
12"
Between Rows

Succession Planting Gladiolus

2
successive plantings in your 163-day season

Sow every 8 weeks. Last sowing by Jun 30 to harvest before frost.

Gladiolus Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 527 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Gladiolus

Gladiolus needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Gladiolus Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

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

Gladiolus 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.

Gladiolus needs ~1,169 GDD — county provides 2,241 GDD Excellent fit

Gladiolus Planting Timeline — Tama County, IA

Gladiolus Planting Calendar

Activity When Date Range
Transplant Outdoors May 5 May 5 – May 19
Direct Sow May 5 May 5 – May 26
Bloom July 28 Jul 28 – Oct 20

Plant 5" deep · 5" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

163 days in Tama County

Growing Tips for Gladiolus in Tama County

Direct sow Gladiolus outdoors after April 28 in Tama County when soil has warmed and frost danger has passed.

General growing tips

Plant corms 4–6 inches deep, pointed end up, as soon as soil reaches 60°F after last frost. Space 4–6 inches apart; rows 12 inches apart. Stake or grow through a support grid — tall varieties reach 4–5 feet and tip in wind. Begin succession plantings every 2 weeks through early July for continuous bloom. Water deeply once a week; mulch to conserve moisture and suppress weeds. Cut spikes for vases when the lowest floret just begins to open. After first killing frost (in cold zones), dig corms, let dry for 3–4 weeks in a ventilated spot, remove cormels, and store in mesh bags at 35–50°F. In zones 7b–8a, corms sometimes survive mild winters in ground with heavy mulch; in zones 8b+, in-ground overwintering is reliable.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Gladiolus in Tama County, IA?

Tama County is in Zone 5a with an average last frost of April 28. Plan your Gladiolus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tama County, IA?

Tama County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 8.

When should I plant Gladiolus in Tama County County, ?

In Tama County County, , plant Gladiolus after the last frost (around April 28) and before the first frost (around October 8). Best results when soil holds above 50°F.

What growing zone is Tama County County, for Gladiolus?

Tama County County sits in USDA Zone 5a. Gladiolus grows reliably in zones 3a through 10b, so it's a good fit here.

Can Gladiolus grow in Tama County County's climate?

Yes — Gladiolus grows well in Tama County County's temperate climate. Tama County County averages a 163-day frost-free season, with last frost around April 28 and first frost around October 8.

🌱

Your Tama County Garden Planner — Free

A 22-page printable planner built for Tama 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 Tama County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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