When to plant Shallot in Union County, IA
The best window to plant Shallot in Union County, is April 9–April 30, when soil warms to 50°F. Last frost typically hits April 23; first frost October 11. A second sowing from August 2 to August 16 extends the harvest into fall.
When to Plant Shallot in Union County, IA
August to-do list for Union County, Iowa
August rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Union County, Iowa.
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Basket week: shallot
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
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Direct-sow shallot for cool weather
Fall crops get sweeter with a light frost. Don't be afraid of cool nights.
To set up a strong September, finish these tasks
- First harvests: shallot
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.
Union County, Iowa is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 11, giving you a growing season of approximately 171 days.
At an elevation of 1,311 feet, Union County receives approximately 39 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.
Union County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-7.3
Drainage
Well Drained
Shallot Planting Risk Windows
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 Union County
How your county's soil matches Shallot's growing requirements.
Soil pH
Your soil pH (6.3–7.3) overlaps with Shallot's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Union County is excellent for Shallot — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.8%) — Shallot will thrive.
How to Plant Shallot
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Shallot Water Budget
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 | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| May | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jun | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Aug | 4.3" | 4" | 0.3" | 💧 Light watering |
| Sep | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Oct | 4.3" | 3" | 1.3" | 💧 Light watering |
| Nov | — | 2.8" | 0" | ❄️ Dormant |
| Dec | — | 2.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Union 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 Planting Timeline — Union County, IA
Shallot Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 19 | Mar 19 – Apr 2 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 9 | Apr 9 – Apr 30 |
| Harvest | July 23 | Jul 23 – Sep 10 |
| Fall Sowing | August 2 | Aug 2 – Aug 16 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
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: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
171 days in Union County
Growing Tips for Shallot in Union County
Direct sow Shallot outdoors after April 23 in Union 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
Check more plant combinations with our Companion Planting Checker →
Shallot in Other Locations
Frequently Asked Questions
When should I plant Shallot in Union County, IA?
Union County is in Zone 5b with an average last frost of April 23. Plan your Shallot planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, IA?
Union County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 11.
When should I plant Shallot in Union County, IA?
In Union County, IA, plant Shallot after the last frost (around April 23) and before the first frost (around October 11). Best results when soil holds above 50°F.
What growing zone is Union County, IA for Shallot?
Union County sits in USDA Zone 5b. Shallot grows reliably in zones 4a through 10b, so it's a good fit here.
Can Shallot grow in Union County's climate?
Yes — Shallot grows well in Union County's temperate climate. Union County averages a 171-day frost-free season, with last frost around April 23 and first frost around October 11.
Your Union County Garden Planner — Free
A 22-page printable planner built for Union 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.