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When to plant Coreopsis in Keyes, CA

Keyes gardeners should plant Coreopsis between February 3 and February 24 in spring. With Keyes's Zone 9b climate (last frost February 24), Coreopsis needs 60–80 days to mature — plant by September 9 for a full harvest.

When to Plant Coreopsis in Keyes, CA

Stanislaus County, California Zone 9b July

July to-do list for Stanislaus County, California

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

Avg. last frost February 24
Avg. first frost November 28
Soil temp (4") 87°F
Watering Critical
Pest pressure High
Daylight 14.4 hrs
  1. Bring in the coreopsis

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

To set up a strong August, finish these tasks
  • 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.

Keyes, California is in USDA Zone 9b. The average last spring frost is February 24 and the first fall frost is November 28, giving you a growing season of approximately 277 days.

At an elevation of 2,887 feet, Stanislaus County receives approximately 15.2 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Coreopsis during the growing season. 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
Keyes, CA (Zone 9b) Year-round
277 days
Last Spring Frost February 24
277 growing days
First Fall Frost November 28

Keyes Soil Profile

Soil Type

Loam

Soil pH

6.5-7.7

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✓ Fits season (93 days to spare)
Start indoors: Dec 12 Transplant: Jan 23 🌸 Bloom: Mar 20 – Aug 21
Recommended (50%) ✓ Fits season (81 days to spare)
Start indoors: Dec 30 Transplant: Feb 10 🌸 Bloom: Apr 7 – Sep 8
Safe Start (90%) ✓ Fits season (46 days to spare)
Start indoors: Feb 21 Transplant: Apr 4 🌸 Bloom: May 30 – Oct 31

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 Keyes

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

Soil pH

Your soil pH (6.5–7.7) overlaps with Coreopsis's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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 277-day season

Sow every 6.9 weeks. Last sowing by Sep 09 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 803 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 3.1" 0" ❄️ Dormant
Feb 2.2" 3.5" 0" ✅ Rainfall sufficient
Mar 2.2" 2.1" 0.1" 💧 Light watering
Apr 2.2" 1.3" 0.9" 💧 Light watering
May 2.2" 0.5" 1.7" 🚿 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" 0.7" 1.5" 🚿 Regular watering
Nov 2.2" 1.5" 0.7" 💧 Light watering
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Stanislaus 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 5,699 GDD Excellent fit

Coreopsis Planting Timeline — Keyes, CA

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors December 30 Dec 30 – Jan 13
Transplant Outdoors February 10 Feb 10 – Feb 24
Direct Sow February 3 Feb 3 – Feb 24
Bloom April 7 Apr 7 – Sep 8

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

Month-by-Month Timeline

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

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: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

277 days in Stanislaus County

Growing Tips for Coreopsis in Keyes

Direct sow Coreopsis outdoors after February 24 in Stanislaus 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.

Stanislaus 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 Keyes, CA?

In Keyes, CA, plant Coreopsis after the last frost (around February 24) and before the first frost (around November 28). Best results when soil holds above 50°F.

What growing zone is Keyes, CA for Coreopsis?

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

Can Coreopsis grow in Keyes's climate?

Yes — Coreopsis grows well in Keyes's temperate climate. Keyes averages a 278-day frost-free season, with last frost around February 24 and first frost around November 28.

🌱

Your Stanislaus County Garden Planner — Free

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