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When to Plant Microgreens in Shasta County, CA

Shasta County, California Zone 9a May

Shasta County, California gardeners: here's your May plan

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

Avg. last frost June 6
Avg. first frost September 21
Soil temp (4") 70°F
Watering Critical
Pest pressure High
Daylight 14.3 hrs
  1. Sow microgreens where they'll grow

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Looking ahead to June
  • Transplants going out: 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.

Shasta County, California is in USDA Zone 9a. The average last spring frost is June 6 and the first fall frost is September 21, giving you a growing season of approximately 107 days.

At an elevation of 81 feet, Shasta County receives approximately 40.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 85°F, providing good warmth for Microgreens during the growing season. Sandy soil warms quickly in spring — great for early planting — but Microgreens will need more frequent watering and organic matter to retain nutrients.

Shasta County, CA (Zone 9a) Short season
107 days
Last Spring Frost June 6
107 growing days
First Fall Frost September 21

Shasta County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Start indoors: Apr 25 Transplant: May 23 🍅 Harvest: May 30 – Jun 27
Recommended (50%) ✓ Fits season (72 days to spare)
Start indoors: May 9 Transplant: Jun 6 🍅 Harvest: Jun 13 – Jul 11
Safe Start (90%) ✓ Fits season (75 days to spare)
Start indoors: May 25 Transplant: Jun 22 🍅 Harvest: Jun 29 – Jul 27

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 Shasta County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Microgreens's range (6.0–7.0), though not a perfect match.

Soil Texture

Sandy soil in Shasta County warms quickly in spring but drains fast. Microgreens will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Microgreens.

How to Plant Microgreens

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Microgreens

21
successive plantings in your 107-day season

Sow every 0.7 weeks. Last sowing by Aug 31 to harvest before frost.

For a dedicated fall crop, sow by Jul 27.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 7.7" 0" ❄️ Dormant
Feb 8" 0" ❄️ Dormant
Mar 6.8" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 1" 0" ❄️ Dormant
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.4" 3.9" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 4.4" 0" ❄️ Dormant
Dec 7.1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Shasta 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 ~192 GDD — county provides 1,471 GDD Excellent fit

Microgreens Planting Timeline — Shasta County, CA

Microgreens Planting Calendar

Activity When Date Range
Start Indoors May 9 May 9 – May 23
Transplant Outdoors June 6 Jun 6 – Jun 20
Direct Sow May 16 May 16 – Jun 6
Harvest June 13 Jun 13 – Jul 11
Fall Sowing July 27 Jul 27 – Aug 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

107 days in Shasta County

Growing Tips for Microgreens in Shasta County

Direct sow Microgreens outdoors after June 06 in Shasta County when soil has warmed and frost danger has passed.

Sandy soil in Shasta County dries quickly — mulch Microgreens with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Your generous 107.0-day season in Shasta County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

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 Shasta County, CA?

Shasta County is in Zone 9a with an average last frost of June 6. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Shasta County, CA?

Shasta County, California is in USDA Hardiness Zone 9a. The average last spring frost is June 6 and first fall frost is September 21.

🌱

Your Shasta County Garden Planner — Free

A 24-page printable planner built for Shasta County (Zone 9a). 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 Shasta County, CA. 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.