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When to Plant Shallot in Story County, IA

Story County, Iowa Zone 5b May

What to do in May

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

Avg. last frost April 30
Avg. first frost October 7
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
Before June arrives, get these ready
  • Starting indoors: shallot

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Shallots are a gourmet allium prized for their complex, sweet, and mild flavor. Each bulb multiplies into a cluster, making them easy and rewarding to grow.

Story County, Iowa is in USDA Zone 5b. The average last spring frost is April 30 and the first fall frost is October 7, giving you a growing season of approximately 160 days.

At an elevation of 1,177 feet, Story County receives approximately 34.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Shallot to ensure they mature before fall.

Story County, IA (Zone 5b) Moderate season
160 days
Last Spring Frost April 30
160 growing days
First Fall Frost October 7
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Story County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jul 23 – Sep 10
Recommended (50%) ✓ Fits season (20 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jul 30 – Sep 17
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Aug 13 – Oct 1

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 Story County

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

Soil pH

Your soil pH (6.0–6.8) is within Shallot's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Shallot will thrive.

How to Plant Shallot

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 142 gal / 100 sq ft

Monthly Watering Guide for Shallot

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

Month Shallot Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.2" 2.1" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

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

Shallot 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.

Shallot needs ~1,365 GDD — county provides 2,080 GDD Excellent fit

Shallot Planting Timeline — Story County, IA

Shallot Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 16 Apr 16 – May 7
Harvest July 30 Jul 30 – Sep 17
Fall Sowing July 29 Jul 29 – Aug 12

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

160 days in Story County

Growing Tips for Shallot in Story County

Direct sow Shallot outdoors after April 30 in Story County when soil has warmed and frost danger has passed.

Common pests for Shallot in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant sets in fall for spring harvest or early spring for summer harvest. Mulch heavily if overwintering. Harvest when tops brown and dry, then cure for storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Shallot in Story County, IA?

Story County is in Zone 5b with an average last frost of April 30. Plan your Shallot planting based on this frost date — see the calendar above for exact timing.

What planting zone is Story County, IA?

Story County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 30 and first fall frost is October 7.

🌱

Your Story County Garden Planner — Free

A 24-page printable planner built for Story County (Zone 5b). 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 Story 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.