Blog

When to plant Shallot in Mapleton, IA

Mapleton's spring Shallot window runs April 12 through May 3. time plantings around the expected last-frost window for best survival. A second sowing from August 1 to August 15 extends the harvest into fall.

When to Plant Shallot in Mapleton, IA

Monona County, Iowa Zone 5a August

August in Monona County, Iowa — your action list

We've pulled the most time-sensitive tasks for Monona County, Iowa this August and put them front and centre. Tackle them in order.

Avg. last frost April 26
Avg. first frost October 10
Soil temp (4") 80°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. It's harvest week for shallot

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

  2. Sow shallot for an autumn harvest

    Your first frost is about 8 weeks away — plenty of time for these to mature.

Looking ahead to September
  • First harvests: shallot

Instant PDF download. No spam, unsubscribe any time.

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.

Mapleton, Iowa is in USDA Zone 5a. The average last spring frost is April 26 and the first fall frost is October 10, giving you a growing season of approximately 167 days.

At an elevation of 732 feet, Monona County receives approximately 35.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Shallot to ensure they mature before fall.

Mapleton, IA (Zone 5a) Moderate season
167 days
Last Spring Frost April 26
167 growing days
First Fall Frost October 10

Mapleton Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.1

Drainage

Well Drained

Shallot Planting Risk Windows

Early Start (70% safe) ✓ Fits season (25 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🍅 Harvest: Jul 21 – Sep 8
Recommended (50%) ✓ Fits season (27 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jul 26 – Sep 13
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Aug 10 – Sep 28

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 Mapleton

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

Soil pH

Your soil pH (5.7–7.1) overlaps with Shallot's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Shallot.

Organic Matter

Organic matter is excellent (4.4%) — 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.

Shallot Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 744 gal / 100 sq ft
Drought risk

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

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 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Monona 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 ~1,286 GDD — county provides 2,045 GDD Excellent fit

Shallot Planting Timeline — Mapleton, IA

Shallot Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors April 26 Apr 26 – May 10
Direct Sow April 12 Apr 12 – May 3
Harvest July 26 Jul 26 – Sep 13
Fall Sowing August 1 Aug 1 – Aug 15

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 Harvest
August Fall Sowing Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

167 days in Monona County

Growing Tips for Shallot in Mapleton

Direct sow Shallot outdoors after April 26 in Monona 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 →

When should I plant Shallot in Mapleton, IA?

In Mapleton, IA, plant Shallot after the last frost (around April 26) and before the first frost (around October 10). Best results when soil holds above 50°F.

What growing zone is Mapleton, IA for Shallot?

Mapleton sits in USDA Zone 5a. Shallot grows reliably in zones 4a through 10b, so it's a good fit here.

Can Shallot grow in Mapleton's climate?

Yes — Shallot grows well in Mapleton's temperate climate. Mapleton averages a 167-day frost-free season, with last frost around April 26 and first frost around October 10.

🌱

Your Monona County Garden Planner — Free

A 22-page printable planner built for Monona 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Monona County, IA. Local conditions may vary. Last updated: August 2026.