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When to Plant Microgreens in Adams County, WA

Adams County, Washington Zone 7a May

Your May planting checklist for Adams County, Washington

May is a pivotal month for Adams County, Washington gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 7
Avg. first frost October 3
Soil temp (4") 55°F
Watering Critical
Pest pressure Low
Daylight 14.9 hrs
  1. Transplant microgreens outside

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Harvest microgreens as they ripen

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to 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.

Adams County, Washington is in USDA Zone 7a. The average last spring frost is May 7 and the first fall frost is October 3, giving you a growing season of approximately 149 days.

At an elevation of 2,402 feet, Adams County receives approximately 17.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°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.

Adams County, WA (Zone 7a) Short season
149 days
Last Spring Frost May 7
149 growing days
First Fall Frost October 3

Adams County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (117 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: May 4 – Jun 1
Recommended (50%) ✓ Fits season (114 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: May 14 – Jun 11
Safe Start (90%) ✓ Fits season (121 days to spare)
Start indoors: Apr 17 Transplant: May 22 🍅 Harvest: May 29 – Jun 26

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 Adams County

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

Soil pH

Your soil pH (5.7–6.4) overlaps with Microgreens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.3%) — Microgreens will thrive.

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

29
successive plantings in your 149-day season

Sow every 0.7 weeks. Last sowing by Sep 12 to harvest before frost.

For a dedicated fall crop, sow by Jul 25.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 824 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 2.7" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.4" 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" 0.4" 3.9" 🚿 Regular watering
Sep 4.3" 0.6" 3.7" 🚿 Regular watering
Oct 4.3" 1.6" 2.7" 🚿 Regular watering
Nov 2.5" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Adams 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 ~256 GDD — county provides 2,719 GDD Excellent fit

Microgreens Planting Timeline — Adams County, WA

Microgreens Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors May 7 May 7 – May 21
Direct Sow April 23 Apr 23 – May 14
Harvest May 14 May 14 – Jun 11
Fall Sowing July 25 Jul 25 – Aug 8

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow Harvest
June Harvest
July Fall Sowing
August Fall Sowing
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: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

149 days in Adams County

Growing Tips for Microgreens in Adams County

Direct sow Microgreens outdoors after May 07 in Adams County when soil has warmed and frost danger has passed.

Your generous 149.0-day season in Adams County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

Adams County receives only 17" 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 Adams County, WA?

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

What planting zone is Adams County, WA?

Adams County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is May 7 and first fall frost is October 3.

🌱

Your Adams County Garden Planner — Free

A 24-page printable planner built for Adams 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.

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 Adams 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.