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When to plant Microgreens in Lewis County, ID

For Microgreens in Lewis County, the safe spring window opens around May 6 and closes around May 27. Last expected frost is May 20, first fall frost September 23, giving a 126-day growing season. A second sowing from July 15 to July 29 extends the harvest into fall.

When to Plant Microgreens in Lewis County, ID

Lewis County, Idaho Zone 6b July

This month in Lewis County, Idaho

Here's what deserves your attention in Lewis County, Idaho this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost May 20
Avg. first frost September 23
Soil temp (4") 67°F
Watering Critical
Pest pressure High
Daylight 15.2 hrs
  1. Plant your fall garden: microgreens

    Your first frost is about 9 weeks away — plenty of time for these to mature.

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Lewis County, Idaho is in USDA Zone 6b. The average last spring frost is May 20 and the first fall frost is September 23, giving you a growing season of approximately 126 days.

At an elevation of 4,861 feet, Lewis County receives approximately 13.5 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Microgreens during the growing season. With low rainfall, drip irrigation is essential for growing Microgreens successfully. Mulch heavily to conserve soil moisture.

Lewis County, ID (Zone 6b) Short season
126 days
Last Spring Frost May 20
126 growing days
First Fall Frost September 23

Lewis County Soil Profile

Soil Type

Loam

Soil pH

6.7-8

Drainage

Well Drained

Microgreens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (92 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: May 19 – Jun 16
Recommended (50%) ✓ Fits season (91 days to spare)
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: May 27 – Jun 24
Safe Start (90%) ✓ Fits season (87 days to spare)
Start indoors: May 6 Transplant: Jun 10 🍅 Harvest: Jun 17 – Jul 15

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 Lewis County

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

Soil pH

Your soil pH (6.7–8.0) is more alkaline than Microgreens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Lewis County is excellent for Microgreens — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Microgreens.

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Microgreens

24
successive plantings in your 126-day season

Sow every 0.7 weeks. Last sowing by Sep 02 to harvest before frost.

For a dedicated fall crop, sow by Jul 15.

Microgreens Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 740 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Microgreens

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

Month Microgreens Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 4.3" 1.7" 2.6" 🚿 Regular watering
Jun 4.3" 0.8" 3.5" 🚿 Regular watering
Jul 4.3" 1.2" 3.1" 🚿 Regular watering
Aug 4.3" 1.4" 2.9" 🚿 Regular watering
Sep 4.3" 1.2" 3.1" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

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

Microgreens 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.

Microgreens needs ~245 GDD — county provides 2,205 GDD Excellent fit

Microgreens Planting Timeline — Lewis County, ID

Microgreens Planting Calendar

Activity When Date Range
Start Indoors April 15 Apr 15 – Apr 29
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 6 May 6 – May 27
Harvest May 27 May 27 – Jun 24
Fall Sowing July 15 Jul 15 – Jul 29

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

126 days in Lewis County

Growing Tips for Microgreens in Lewis County

Direct sow Microgreens outdoors after May 20 in Lewis County when soil has warmed and frost danger has passed.

Your generous 126.0-day season in Lewis County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

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

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Lewis County, ID?

Lewis County is in Zone 6b with an average last frost of May 20. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lewis County, ID?

Lewis County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 20 and first fall frost is September 23.

When should I plant Microgreens in Lewis County, ID?

In Lewis County, ID, plant Microgreens after the last frost (around May 20) and before the first frost (around September 23). Best results when soil holds above 50°F.

What growing zone is Lewis County, ID for Microgreens?

Lewis County sits in USDA Zone 6b. Microgreens grows reliably in zones 1a through 13b, so it's a good fit here.

Can Microgreens grow in Lewis County's climate?

Yes — Microgreens grows well in Lewis County's temperate climate. Lewis County averages a 126-day frost-free season, with last frost around May 20 and first frost around September 23.

🌱

Your Lewis County Garden Planner — Free

A 22-page printable planner built for Lewis 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 Lewis County, ID. Local conditions may vary. Last updated: July 2026.

Sources & credits

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