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When to Plant Coreopsis in Grant County, NM

Grant County, New Mexico Zone 7b August

Your August gardening checklist

A quick August briefing for Grant County, New Mexico gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 27
Avg. first frost October 22
Soil temp (4") 76°F
Watering Moderate
Pest pressure High
Daylight 13.2 hrs
  1. Collect coreopsis at their peak

    If you can't use it all right away, check the food-preservation section of your planner.

September will be here before you know it — start on
  • 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.

Grant County, New Mexico is in USDA Zone 7b. The average last spring frost is April 27 and the first fall frost is October 22, giving you a growing season of approximately 178 days.

At an elevation of 3,721 feet, Grant County receives approximately 15.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 92°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.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Grant County, NM (Zone 7b) Moderate season
178 days
Last Spring Frost April 27
178 growing days
First Fall Frost October 22

Grant County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.9-8.2

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 13 Transplant: Apr 24 🌸 Bloom: Jun 26 – Nov 13
Recommended (50%) ✗ May not fit
Start indoors: Feb 23 Transplant: May 4 🌸 Bloom: Jul 6 – Nov 23
Safe Start (90%) ✗ May not fit
Start indoors: Mar 20 Transplant: May 29 🌸 Bloom: Jul 31 – Dec 18

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 Grant County

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

Soil pH

Your soil pH (6.9–8.2) is more alkaline than Coreopsis prefers (5.5–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Grant 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 (0.8%). Add 2-3 inches of compost before planting Coreopsis.

How to Plant Coreopsis

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

Succession Planting Coreopsis

3
successive plantings in your 178-day season

Sow every 6.9 weeks. Last sowing by Aug 03 to harvest before frost.

Coreopsis Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 527 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 0.8" 0" ❄️ Dormant
Apr 2.2" 0.5" 1.7" 🚿 Regular watering
May 2.2" 0.3" 1.9" 🚿 Regular watering
Jun 2.2" 0.6" 1.6" 🚿 Regular watering
Jul 2.2" 2.8" 0" ✅ Rainfall sufficient
Aug 2.2" 2.8" 0" ✅ Rainfall sufficient
Sep 2.2" 2.4" 0" ✅ Rainfall sufficient
Oct 2.2" 1.6" 0.6" 💧 Light watering
Nov 0.9" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Grant 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 ~1,330 GDD — county provides 3,382 GDD Excellent fit

Coreopsis Planting Timeline — Grant County, NM

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors February 23 Feb 23 – Mar 9
Transplant Outdoors May 4 May 4 – May 18
Direct Sow April 27 Apr 27 – May 18
Bloom July 6 Jul 6 – Nov 23

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Direct Sow
May Transplant Outdoors Direct Sow
June
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 7b

📆 Growing Season

178 days in Grant County

Growing Tips for Coreopsis in Grant County

Direct sow Coreopsis outdoors after April 27 in Grant County when soil has warmed and frost danger has passed.

Sandy soil in Grant 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.

Grant County receives only 16" 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 →

Frequently Asked Questions

When should I plant Coreopsis in Grant County, NM?

Grant County is in Zone 7b with an average last frost of April 27. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant County, NM?

Grant County, New Mexico is in USDA Hardiness Zone 7b. The average last spring frost is April 27 and first fall frost is October 22.

🌱

Your Grant County Garden Planner — Free

A 22-page printable planner built for Grant County (Zone 7b). 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 Grant County, NM. Local conditions may vary. Last updated: August 2026.

Sources & credits

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