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When to Plant Microgreens in Boise County, ID

Boise County, Idaho Zone 7a May

May in Boise County, Idaho — your action list

Each item below is timed to Boise County, Idaho's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 18
Avg. first frost September 27
Soil temp (4") 34°F
Watering Moderate
Pest pressure Low
Daylight 14.6 hrs
  1. Time to transplant microgreens

    Your last frost (May 18) has passed. These warm-season crops can handle outdoor soil now.

  2. Outdoor sowing time: microgreens

    Your soil is 34°F — warm enough for these to germinate without babying.

  3. It's harvest week for microgreens

    If you can't use it all right away, check the food-preservation section of your planner.

A few tasks this May that'll pay off in June
  • Starting indoors: microgreens
  • First harvests: microgreens

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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.

Boise County, Idaho is in USDA Zone 7a. The average last spring frost is May 18 and the first fall frost is September 27, giving you a growing season of approximately 132 days.

At an elevation of 8,023 feet, Boise County receives approximately 24.3 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Microgreens during the growing season.

Boise County, ID (Zone 7a) Short season
132 days
Last Spring Frost May 18
132 growing days
First Fall Frost September 27

Boise County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (93 days to spare)
Start indoors: Mar 31 Transplant: May 5 🍅 Harvest: May 12 – Jun 9
Recommended (50%) ✓ Fits season (97 days to spare)
Start indoors: Apr 13 Transplant: May 18 🍅 Harvest: May 25 – Jun 22
Safe Start (90%) ✓ Fits season (96 days to spare)
Start indoors: May 12 Transplant: Jun 16 🍅 Harvest: Jun 23 – Jul 21

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 Boise County

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

Soil pH

Your soil pH (6.7–7.7) is more alkaline than Microgreens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). 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

26
successive plantings in your 132-day season

Sow every 0.7 weeks. Last sowing by Sep 06 to harvest before frost.

For a dedicated fall crop, sow by Jul 19.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 320 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.8" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 4.3" 3" 1.3" 💧 Light watering
Jun 4.3" 1.9" 2.4" 🚿 Regular watering
Jul 4.3" 1.8" 2.5" 🚿 Regular watering
Aug 4.3" 2.8" 1.5" 💧 Light watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 2.4" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Boise 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 ~203 GDD — county provides 1,914 GDD Excellent fit

Microgreens Planting Timeline — Boise County, ID

Microgreens Planting Calendar

Activity When Date Range
Start Indoors April 13 Apr 13 – Apr 27
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 4 May 4 – May 25
Harvest May 25 May 25 – Jun 22
Fall Sowing July 19 Jul 19 – Aug 2

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 Fall Sowing
September
October
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

132 days in Boise County

Growing Tips for Microgreens in Boise County

Direct sow Microgreens outdoors after May 18 in Boise County when soil has warmed and frost danger has passed.

Your generous 132.0-day season in Boise County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

Boise County receives only 24" 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 Boise County, ID?

Boise County is in Zone 7a with an average last frost of May 18. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Boise County, ID?

Boise County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is May 18 and first fall frost is September 27.

🌱

Your Boise County Garden Planner — Free

A 24-page printable planner built for Boise County (Zone 7a). 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 Boise County, ID. 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.