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When to Plant Shallot in Whitman County, WA

Whitman County, Washington Zone 6b May

What to do in May

We've pulled the most time-sensitive tasks for Whitman County, Washington this May and put them front and centre. Tackle them in order.

Avg. last frost May 10
Avg. first frost September 29
Soil temp (4") 59°F
Watering Critical
Pest pressure Low
Daylight 14.8 hrs
  1. Move shallot into the garden

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

Get ahead of June
  • 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.

Whitman County, Washington is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is September 29, giving you a growing season of approximately 142 days.

At an elevation of 1,541 feet, Whitman County receives approximately 14.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Shallot during the growing season. With low rainfall, drip irrigation is essential for growing Shallot successfully. Mulch heavily to conserve soil moisture.

Whitman County, WA (Zone 6b) Short season
142 days
Last Spring Frost May 10
142 growing days
First Fall Frost September 29
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Whitman County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Mar 25 Transplant: Apr 29 🍅 Harvest: Jul 29 – Sep 16
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Aug 9 – Sep 27
Safe Start (90%) ✗ May not fit
Start indoors: May 2 Transplant: Jun 6 🍅 Harvest: Sep 5 – Oct 24

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 Whitman County

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

Soil pH

Your soil pH (5.5–6.7) overlaps with Shallot's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — 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
0.4″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 722 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 2.2" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 4.3" 0.8" 3.5" 🚿 Regular watering
Jun 4.3" 0.6" 3.7" 🚿 Regular watering
Jul 4.3" 0.3" 4" 🚿 Regular watering
Aug 4.3" 0.2" 4.1" 🚿 Regular watering
Sep 4.3" 0.6" 3.7" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Whitman 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 ~1,680 GDD — county provides 2,272 GDD Excellent fit

Shallot Planting Timeline — Whitman County, WA

Shallot Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 10 May 10 – May 24
Direct Sow April 26 Apr 26 – May 17
Harvest August 9 Aug 9 – Sep 27
Fall Sowing July 21 Jul 21 – Aug 4

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Fall Sowing
August Fall Sowing Harvest
September Harvest
October
November
December
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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 6b

📆 Growing Season

142 days in Whitman County

Growing Tips for Shallot in Whitman County

Direct sow Shallot outdoors after May 10 in Whitman 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.

Whitman County receives only 14" of rain annually. Shallot needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Whitman County, WA?

Whitman County is in Zone 6b with an average last frost of May 10. Plan your Shallot planting based on this frost date — see the calendar above for exact timing.

What planting zone is Whitman County, WA?

Whitman County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 10 and first fall frost is September 29.

🌱

Your Whitman County Garden Planner — Free

A 24-page printable planner built for Whitman County (Zone 6b). 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 Whitman County, WA. 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.