When to Plant Coreopsis in Sierra County, NM
July in Sierra County, New Mexico — your action list
Each item below is timed to Sierra County, New Mexico's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Pick coreopsis
If you can't use it all right away, check the food-preservation section of your planner.
Coming up in August — start thinking about
- First harvests: coreopsis
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.
Sierra County, New Mexico is in USDA Zone 8a. The average last spring frost is April 15 and the first fall frost is October 26, giving you a growing season of approximately 194 days.
At an elevation of 4,898 feet, Sierra County receives approximately 17.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 88°F, providing good warmth for Coreopsis during the growing season. Sandy soil warms quickly in spring — great for early planting — but Coreopsis will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Coreopsis successfully. Mulch heavily to conserve soil moisture.
Sierra County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.3-8.5
Drainage
Well Drained
Coreopsis 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 Sierra County
How your county's soil matches Coreopsis's growing requirements.
Soil pH
Your soil pH (7.3–8.5) is more alkaline than Coreopsis prefers (5.5–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Sierra County warms quickly in spring but drains fast. Coreopsis will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Coreopsis.
Organic Matter
Organic matter is low (0.7%). Add 2-3 inches of compost before planting Coreopsis.
How to Plant Coreopsis
Succession Planting Coreopsis
Sow every 6.9 weeks. Last sowing by Aug 07 to harvest before frost.
Coreopsis Water Budget
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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1" | 0" | ❄️ Dormant |
| Apr | 2.2" | 0.6" | 1.6" | 🚿 Regular watering |
| May | 2.2" | 0.4" | 1.8" | 🚿 Regular watering |
| Jun | 2.2" | 0.5" | 1.7" | 🚿 Regular watering |
| Jul | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Sierra 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 Planting Timeline — Sierra County, NM
Coreopsis Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 18 | Feb 18 – Mar 4 |
| Transplant Outdoors | April 15 | Apr 15 – Apr 29 |
| Direct Sow | April 8 | Apr 8 – Apr 29 |
| Bloom | June 17 | Jun 17 – Nov 11 |
Plant 0.1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 · 1-2 times/week
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 8a
📆 Growing Season
194 days in Sierra County
Growing Tips for Coreopsis in Sierra County
Direct sow Coreopsis outdoors after April 15 in Sierra County when soil has warmed and frost danger has passed.
Sandy soil in Sierra County dries quickly — mulch Coreopsis with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
Common pests for Coreopsis in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Sierra County receives only 17" 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 →
Coreopsis in Other Locations
Frequently Asked Questions
When should I plant Coreopsis in Sierra County, NM?
Sierra County is in Zone 8a with an average last frost of April 15. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sierra County, NM?
Sierra County, New Mexico is in USDA Hardiness Zone 8a. The average last spring frost is April 15 and first fall frost is October 26.
Your Sierra County Garden Planner — Free
A 22-page printable planner built for Sierra County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.