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When to plant Coreopsis in Yuba County, CA

In Yuba County, plant Coreopsis in spring between April 1 and April 22, once soil temps hold above 50°F. Yuba County's last frost averages April 22, so aim for a steady week of warm soil before planting. For a fall crop, sow between and — roughly 60–80 days before the first frost on November 9.

When to Plant Coreopsis in Yuba County, CA

Yuba County, California Zone 9b June

Top priorities for Yuba County, California gardeners in June

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

Avg. last frost April 22
Avg. first frost November 9
Soil temp (4") 87°F
Watering Critical
Pest pressure High
Daylight 14.8 hrs
  1. Start coreopsis indoors

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. It's harvest week for coreopsis

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Looking ahead to July
  • First harvests: coreopsis

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Coreopsis (Tickseed) is a cheerful, long-blooming native perennial that produces a continuous flush of bright yellow, gold, or bi-colored daisy-like flowers from early summer well into fall. One of the most reliable cut-and-come-again bloomers in the perennial garden, it thrives in hot, dry, sunny conditions and poor soil where many competitors struggle. An invaluable nectar source for native bees and butterflies, and a butterfly host plant for several species.

Yuba County, California is in USDA Zone 9b. The average last spring frost is April 22 and the first fall frost is November 9, giving you a growing season of approximately 201 days.

At an elevation of 303 feet, Yuba County receives approximately 26.5 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Coreopsis during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Yuba County, CA (Zone 9b) Long season
201 days
Last Spring Frost April 22
201 growing days
First Fall Frost November 9

Yuba County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.3

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✓ Fits season (4 days to spare)
Start indoors: Feb 17 Transplant: Mar 31 🌸 Bloom: May 26 – Oct 27
Recommended (50%) ✓ Fits season (5 days to spare)
Start indoors: Feb 25 Transplant: Apr 8 🌸 Bloom: Jun 3 – Nov 4
Safe Start (90%) ✗ May not fit
Start indoors: Apr 2 Transplant: May 14 🌸 Bloom: Jul 9 – Dec 10

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 Yuba County

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

Soil pH

Your soil pH (6.3–7.3) is within Coreopsis's preferred range (5.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Coreopsis.

How to Plant Coreopsis

0.1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Coreopsis

3
successive plantings in your 201-day season

Sow every 6.9 weeks. Last sowing by Aug 21 to harvest before frost.

Coreopsis Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/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 Coreopsis

Coreopsis needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Coreopsis Needs Rainfall You Supplement Action
Jan 4.9" 0" ❄️ Dormant
Feb 5.6" 0" ❄️ Dormant
Mar 4.6" 0" ❄️ Dormant
Apr 2.2" 2.2" 0" ✅ Rainfall sufficient
May 2.2" 0.7" 1.5" 🚿 Regular watering
Jun 2.2" 0.2" 2" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.3" 1.9" 🚿 Regular watering
Oct 2.2" 1.1" 1.1" 🚿 Regular watering
Nov 2.2" 2.8" 0" ✅ Rainfall sufficient
Dec 4.1" 0" ❄️ Dormant

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

Coreopsis 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.

Coreopsis needs ~1,435 GDD — county provides 4,120 GDD Excellent fit

Coreopsis Planting Timeline — Yuba County, CA

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors February 25 Feb 25 – Mar 11
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow April 1 Apr 1 – Apr 22
Bloom June 3 Jun 3 – Nov 4

Plant 0.1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

201 days in Yuba County

Growing Tips for Coreopsis in Yuba County

Direct sow Coreopsis outdoors after April 22 in Yuba County when soil has warmed and frost danger has passed.

Common pests for Coreopsis in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 8–10 weeks before last frost or direct sow after last frost. Seeds germinate easily without stratification. Thrives in poor to average, well-drained soil — rich soil promotes foliage over flowers. Drought tolerant once established; overwatering is the most common mistake. Deadhead spent blooms to maintain continuous flowering through the season. Shear plants by one-third in midsummer for a fresh flush of late-season blooms. Year 2+ plants bloom most heavily. Divide every 2–3 years in early spring to rejuvenate crowded clumps.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Coreopsis in Yuba County, CA?

Yuba County is in Zone 9b with an average last frost of April 22. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yuba County, CA?

Yuba County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 22 and first fall frost is November 9.

When should I plant Coreopsis in Yuba County, CA?

In Yuba County, CA, plant Coreopsis after the last frost (around April 22) and before the first frost (around November 9). Best results when soil holds above 50°F.

What growing zone is Yuba County, CA for Coreopsis?

Yuba County sits in USDA Zone 9b. Coreopsis grows reliably in zones 3a through 9b, so it's a good fit here.

Can Coreopsis grow in Yuba County's climate?

Yes — Coreopsis grows well in Yuba County's temperate climate. Yuba County averages a 201-day frost-free season, with last frost around April 22 and first frost around November 9.

🌱

Your Yuba County Garden Planner — Free

A 22-page printable planner built for Yuba 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 Yuba County, CA. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.