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When to Plant Brussels Sprouts in Nevada County, CA

Nevada County, California Zone 9a May

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

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

Avg. last frost May 10
Avg. first frost October 22
Soil temp (4") 63°F
Watering High
Pest pressure Moderate
Daylight 14.2 hrs
  1. Transplant brussels sprouts outside

    Frost risk is low now in Nevada County, California. If you've been covering beds overnight, you can stop.

Get ahead of June
  • Starting indoors: brussels sprouts

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Brussels sprouts are a cold-hardy brassica that produces miniature cabbage-like heads along a tall stalk. Flavor improves after a light frost.

Nevada County, California is in USDA Zone 9a. The average last spring frost is May 10 and the first fall frost is October 22, giving you a growing season of approximately 165 days.

At an elevation of 2,745 feet, Nevada County receives approximately 44.7 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Brussels Sprouts to ensure they mature before fall.

Nevada County, CA (Zone 9a) Moderate season
165 days
Last Spring Frost May 10
165 growing days
First Fall Frost October 22
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Nevada County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Mar 28 Transplant: Apr 25 🍅 Harvest: Jul 25 – Sep 19
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Apr 12 Transplant: May 10 🍅 Harvest: Aug 9 – Oct 4
Safe Start (90%) ✓ Fits season (26 days to spare)
Start indoors: May 8 Transplant: Jun 5 🍅 Harvest: Sep 4 – Oct 30

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 Nevada County

How your county's soil matches Brussels Sprouts's growing requirements.

Soil pH

Your soil pH (6.8–7.5) is within Brussels Sprouts's preferred range (6.0–7.5).

Soil Texture

The loam soil in Nevada County is excellent for Brussels Sprouts — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Brussels Sprouts.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Brussels Sprouts.

How to Plant Brussels Sprouts

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.1″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 57 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Brussels Sprouts

Brussels Sprouts needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Brussels Sprouts Needs Rainfall You Supplement Action
Jan 9.9" 0" ❄️ Dormant
Feb 8.7" 0" ❄️ Dormant
Mar 7.9" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 3.9" 1.3" 2.6" 🚿 Regular watering
Jun 3.9" 0.2" 3.7" 🚿 Regular watering
Jul 3.9" 0" 3.9" 🚿 Regular watering
Aug 3.9" 0" 3.9" 🚿 Regular watering
Sep 3.9" 0.4" 3.5" 🚿 Regular watering
Oct 3.9" 1.9" 2" 🚿 Regular watering
Nov 4.6" 0" ❄️ Dormant
Dec 6.8" 0" ❄️ Dormant

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

Brussels Sprouts 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.

Brussels Sprouts needs ~1,348 GDD — county provides 2,021 GDD Excellent fit

Brussels Sprouts Planting Timeline — Nevada County, CA

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors April 12 Apr 12 – Apr 26
Transplant Outdoors May 10 May 10 – May 24
Direct Sow April 19 Apr 19 – May 10
Harvest August 9 Aug 9 – Oct 4
Fall Sowing August 27 Aug 27 – Sep 10

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Only during dry spells

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9a

📆 Growing Season

165 days in Nevada County

Growing Tips for Brussels Sprouts in Nevada County

Direct sow Brussels Sprouts outdoors after May 10 in Nevada County when soil has warmed and frost danger has passed.

Common pests for Brussels Sprouts in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 12-14 weeks before first fall frost. Stake tall plants to prevent toppling. Remove lower leaves as sprouts develop to improve air circulation.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Brussels Sprouts in Nevada County, CA?

Nevada County is in Zone 9a with an average last frost of May 10. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Nevada County, CA?

Nevada County, California is in USDA Hardiness Zone 9a. The average last spring frost is May 10 and first fall frost is October 22.

🌱

Your Nevada County Garden Planner — Free

A 24-page printable planner built for Nevada 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 Nevada 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.