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When to Plant Microgreens in San Benito County, CA

San Benito County, California Zone 9b May

Your May planting checklist for San Benito County, California

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

Avg. last frost February 21
Avg. first frost November 29
Soil temp (4") 76°F
Watering Critical
Pest pressure High
Daylight 14 hrs

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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.

San Benito County, California is in USDA Zone 9b. The average last spring frost is February 21 and the first fall frost is November 29, giving you a growing season of approximately 281 days.

At an elevation of 149 feet, San Benito County receives approximately 13 inches of rainfall annually with predominantly loam soil. Summer highs average 94°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.

San Benito County, CA (Zone 9b) Year-round
281 days
Last Spring Frost February 21
281 growing days
First Fall Frost November 29

San Benito County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (255 days to spare)
Start indoors: Jan 8 Transplant: Feb 5 🍅 Harvest: Feb 12 – Mar 12
Recommended (50%) ✓ Fits season (246 days to spare)
Start indoors: Jan 24 Transplant: Feb 21 🍅 Harvest: Feb 28 – Mar 28
Safe Start (90%) ✓ Fits season (222 days to spare)
Start indoors: Mar 11 Transplant: Apr 8 🍅 Harvest: Apr 15 – May 13

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 San Benito County

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

Soil pH

Your soil pH (6.5–7.4) overlaps with Microgreens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). 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

55
successive plantings in your 281-day season

Sow every 0.7 weeks. Last sowing by Nov 08 to harvest before frost.

For a dedicated fall crop, sow by Oct 04.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 2,429 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 2.5" 0" ❄️ Dormant
Feb 4.3" 2.6" 1.7" 💧 Light watering
Mar 4.3" 2.2" 2.1" 💧 Light watering
Apr 4.3" 1.1" 3.2" 🚿 Regular watering
May 4.3" 0.3" 4" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.1" 4.2" 🚿 Regular watering
Oct 4.3" 0.5" 3.8" 🚿 Regular watering
Nov 4.3" 1.3" 3" 🚿 Regular watering
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in San Benito 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 ~287 GDD — county provides 5,781 GDD Excellent fit

Microgreens Planting Timeline — San Benito County, CA

Microgreens Planting Calendar

Activity When Date Range
Start Indoors January 24 Jan 24 – Feb 7
Transplant Outdoors February 21 Feb 21 – Mar 7
Direct Sow January 31 Jan 31 – Feb 21
Harvest February 28 Feb 28 – Mar 28
Fall Sowing October 4 Oct 4 – Oct 18

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

281 days in San Benito County

Growing Tips for Microgreens in San Benito County

Direct sow Microgreens outdoors after February 21 in San Benito County when soil has warmed and frost danger has passed.

Your generous 282.0-day season in San Benito County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

San Benito County receives only 13" 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 San Benito County, CA?

San Benito County is in Zone 9b with an average last frost of February 21. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Benito County, CA?

San Benito County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 21 and first fall frost is November 29.

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Your San Benito County Garden Planner — Free

A 24-page printable planner built for San Benito County (Zone 9b). 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 San Benito 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.