When to plant Cosmos in Sutter County, CA
Aim to plant Cosmos in Sutter County on or after January 28; the window stays open through February 18. Sutter County's 267-day frost-free season gives you plenty of room for a spring and fall cycle.
When to Plant Cosmos in Sutter County, CA
What to do in June
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Sutter County, California.
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It's harvest week for cosmos
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
A few tasks this June that'll pay off in July
- First harvests: cosmos
Cosmos (Cosmos bipinnatus) is an airy, feathery-foliaged cottage garden annual from Mexico that thrives on neglect. It produces delicate daisy-like blooms in shades of pink, white, and magenta from midsummer until frost. Cosmos is a prolific self-sower — once established in a garden it often returns year after year without replanting. Excellent habitat plant for beneficial insects.
Sutter County, California is in USDA Zone 9b. The average last spring frost is March 4 and the first fall frost is November 26, giving you a growing season of approximately 267 days.
At an elevation of 484 feet, Sutter County receives approximately 21.4 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Cosmos during the growing season.
Sutter County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.7
Drainage
Well Drained
Cosmos Planting Risk Windows
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 Sutter County
How your county's soil matches Cosmos's growing requirements.
Soil pH
Your soil pH (6.8–7.7) is within Cosmos's preferred range (6.0–8.0).
Soil Texture
The loam soil in Sutter County is excellent for Cosmos — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Cosmos.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Cosmos.
How to Plant Cosmos
Succession Planting Cosmos
Sow every 6.9 weeks. Last sowing by Aug 28 to harvest before frost.
Cosmos Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Cosmos
Cosmos 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 | Cosmos Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 4.6" | 0" | ❄️ Dormant |
| Feb | — | 4.2" | 0" | ❄️ Dormant |
| Mar | 2.2" | 3.7" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| May | 2.2" | 0.6" | 1.6" | 🚿 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" | 0.9" | 1.3" | 🚿 Regular watering |
| Nov | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Dec | — | 3.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Sutter County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Cosmos 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.
Cosmos Planting Timeline — Sutter County, CA
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 4 | Feb 4 – Feb 18 |
| Transplant Outdoors | January 28 | Jan 28 – Feb 11 |
| Direct Sow | January 28 | Jan 28 – Feb 18 |
| Bloom | April 8 | Apr 8 – Oct 7 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Transplant Outdoors Direct Sow |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | — |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · 1-2 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: ideal
🗺️ USDA Zone
Zone 9b
📆 Growing Season
267 days in Sutter County
Growing Tips for Cosmos in Sutter County
Direct sow Cosmos outdoors after March 04 in Sutter County when soil has warmed and frost danger has passed.
Common pests for Cosmos in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Sutter County receives only 21" of rain annually. Cosmos needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Direct-sow after last frost; cosmos germinates readily at 65-80°F in 7-10 days. Avoid rich soil — excess fertility produces lush foliage at the expense of blooms. Cosmos tolerates poor, dry soil exceptionally well. Pinch seedlings at 8 inches to encourage branching. Self-sows freely; allow some seed heads to mature and drop for a no-fuss perennial effect in warm climates.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Cosmos in Other Locations
Frequently Asked Questions
When should I plant Cosmos in Sutter County, CA?
Sutter County is in Zone 9b with an average last frost of March 4. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sutter County, CA?
Sutter County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 4 and first fall frost is November 26.
When should I plant Cosmos in Sutter County, CA?
In Sutter County, CA, plant Cosmos after the last frost (around March 4) and before the first frost (around November 26). Best results when soil holds above 50°F.
What growing zone is Sutter County, CA for Cosmos?
Sutter County sits in USDA Zone 9b. Cosmos grows reliably in zones 2a through 11b, so it's a good fit here.
Can Cosmos grow in Sutter County's climate?
Yes — Cosmos grows well in Sutter County's temperate climate. Sutter County averages a 267-day frost-free season, with last frost around March 4 and first frost around November 26.
Your Sutter County Garden Planner — Free
A 22-page printable planner built for Sutter 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.