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When to Plant Rosemary in Grant County, NM

Grant County, New Mexico Zone 7b May

Your May game plan for Grant County, New Mexico

Each item below is timed to Grant County, New Mexico's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 27
Avg. first frost October 22
Soil temp (4") 58°F
Watering Critical
Pest pressure Moderate
Daylight 13.7 hrs
  1. Move rosemary from tray to bed

    Frost risk is low now in Grant County, New Mexico. If you've been covering beds overnight, you can stop.

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Rosemary is an aromatic evergreen shrub with needle-like leaves and a piney, citrus flavor. It is a Mediterranean herb that thrives in warm, dry conditions.

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 Rosemary during the growing season. Sandy soil warms quickly in spring — great for early planting — but Rosemary will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Rosemary successfully. Mulch heavily to conserve soil moisture.

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

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 24 🍅 Harvest: Jul 17 – Dec 4
Recommended (50%) ✗ May not fit
Transplant: May 4 🍅 Harvest: Jul 27 – Dec 14
Safe Start (90%) ✓ Fits season (303 days to spare)
Transplant: May 29 🍅 Harvest: Aug 21 – Jan 8

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 Rosemary's growing requirements.

Soil pH

Your soil pH (6.9–8.2) is more alkaline than Rosemary prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Grant County warms quickly in spring but drains fast. Rosemary will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Rosemary.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting Rosemary.

How to Plant Rosemary

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Rosemary

2
successive plantings in your 178-day season

Sow every 9.1 weeks. Last sowing by Apr 25 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.4″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 33 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Rosemary

Rosemary needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Rosemary Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 0.8" 0" ❄️ Dormant
Apr 1.3" 0.5" 0.8" 🚿 Regular watering
May 1.3" 0.3" 1" 🚿 Regular watering
Jun 1.3" 0.6" 0.7" 🚿 Regular watering
Jul 1.3" 2.8" 0" ✅ Rainfall sufficient
Aug 1.3" 2.8" 0" ✅ Rainfall sufficient
Sep 1.3" 2.4" 0" ✅ Rainfall sufficient
Oct 1.3" 1.6" 0" ✅ Rainfall sufficient
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.

Rosemary 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.

Rosemary needs ~2,470 GDD — county provides 3,382 GDD Excellent fit

Rosemary Planting Timeline — Grant County, NM

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors May 4 May 4 – May 18
Harvest July 27 Jul 27 – Dec 14

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
October Harvest
November Harvest
December Harvest

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Only during dry spells

📅 Days to Maturity

80–180 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7b

📆 Growing Season

178 days in Grant County

Growing Tips for Rosemary in Grant County

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

Sandy soil in Grant County dries quickly — mulch Rosemary with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Your 178.0-day growing season in Grant County is tight for Rosemary (80.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Grow in well-drained soil and avoid overwatering. In cold climates, grow in containers and bring indoors for winter. Propagate from stem cuttings for faster results than seed.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rosemary in Grant County, NM?

Grant County is in Zone 7b with an average last frost of April 27. Plan your Rosemary 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.

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Your Grant County Garden Planner — Free

A 24-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: May 2026.

Sources & credits

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