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When to plant Coreopsis in Fowler, CA

For Coreopsis in Fowler, the safe spring window opens around February 9 and closes around March 2. Last expected frost is March 2, first fall frost November 23, giving a 266-day growing season.

When to Plant Coreopsis in Fowler, CA

Fresno County, California Zone 9b June

Your June planting checklist for Fresno County, California

Here's what deserves your attention in Fresno County, California this month. Everything below is tailored to Zone 9b and timed around your local frost dates.

Avg. last frost March 2
Avg. first frost November 23
Soil temp (4") 82°F
Watering Critical
Pest pressure High
Daylight 14.5 hrs
  1. Bring in the coreopsis

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

A few tasks this June that'll pay off in 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.

Fowler, California is in USDA Zone 9b. The average last spring frost is March 2 and the first fall frost is November 23, giving you a growing season of approximately 266 days.

At an elevation of 2,276 feet, Fresno County receives approximately 14.9 inches of rainfall annually with predominantly loam soil. Summer highs average 100°F, so Coreopsis may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Coreopsis successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Fowler, CA (Zone 9b) Long season
266 days
Last Spring Frost March 2
266 growing days
First Fall Frost November 23

Fowler Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✓ Fits season (71 days to spare)
Start indoors: Dec 22 Transplant: Feb 2 🌸 Bloom: Mar 30 – Aug 31
Recommended (50%) ✓ Fits season (70 days to spare)
Start indoors: Jan 5 Transplant: Feb 16 🌸 Bloom: Apr 13 – Sep 14
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🌸 Bloom: Jun 22 – Nov 23

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 Fowler

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

Soil pH

Your soil pH (6.5–7.5) is within Coreopsis's preferred range (5.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Coreopsis.

How to Plant Coreopsis

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

Succession Planting Coreopsis

5
successive plantings in your 266-day season

Sow every 6.9 weeks. Last sowing by Sep 04 to harvest before frost.

Coreopsis Water Budget

Plant needs
0.5″/week
Rainfall provides
0.2″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 752 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 2.8" 0" ❄️ Dormant
Feb 3.3" 0" ❄️ Dormant
Mar 2.2" 2.3" 0" ✅ Rainfall sufficient
Apr 2.2" 1" 1.2" 🚿 Regular watering
May 2.2" 0.4" 1.8" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.2" 2" 🚿 Regular watering
Oct 2.2" 0.6" 1.6" 🚿 Regular watering
Nov 2.2" 1.3" 0.9" 💧 Light watering
Dec 2.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Fresno 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 ~1,750 GDD — county provides 6,650 GDD Excellent fit

Coreopsis Planting Timeline — Fowler, CA

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors January 5 Jan 5 – Jan 19
Transplant Outdoors February 16 Feb 16 – Mar 2
Direct Sow February 9 Feb 9 – Mar 2
Bloom April 13 Apr 13 – Sep 14

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

266 days in Fresno County

Growing Tips for Coreopsis in Fowler

Direct sow Coreopsis outdoors after March 02 in Fresno County when soil has warmed and frost danger has passed.

With summer highs reaching 100°F in Fresno County, provide afternoon shade for Coreopsis and water deeply in the morning.

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

Fresno County receives only 15" of rain annually. Coreopsis needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 →

When should I plant Coreopsis in Fowler, CA?

In Fowler, CA, plant Coreopsis after the last frost (around March 2) and before the first frost (around November 23). Best results when soil holds above 50°F.

What growing zone is Fowler, CA for Coreopsis?

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

Can Coreopsis grow in Fowler's climate?

Yes — Coreopsis grows well in Fowler's temperate climate. Fowler averages a 266-day frost-free season, with last frost around March 2 and first frost around November 23.

🌱

Your Fresno County Garden Planner — Free

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