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When to Plant Hyssop in Sierra County, NM

Sierra County, New Mexico Zone 8a May

This month in Sierra County, New Mexico

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Sierra County, New Mexico.

Avg. last frost April 15
Avg. first frost October 26
Soil temp (4") 55°F
Watering Critical
Pest pressure Moderate
Daylight 13.7 hrs

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Hyssop is a semi-evergreen perennial herb with intense blue flower spikes that attract bees and butterflies. It has a minty, slightly bitter flavor used in liqueurs and teas.

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

Sierra County, NM (Zone 8a) Moderate season
194 days
Last Spring Frost April 15
194 growing days
First Fall Frost October 26

Sierra County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (65 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 15 – Aug 17
Recommended (50%) ✓ Fits season (54 days to spare)
Transplant: Apr 22 🍅 Harvest: Jul 1 – Sep 2
Safe Start (90%) ✓ Fits season (59 days to spare)
Transplant: May 11 🍅 Harvest: Jul 20 – Sep 21

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 Hyssop's growing requirements.

Soil pH

Your soil pH (7.3–8.5) overlaps with Hyssop's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Hyssop.

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Hyssop.

How to Plant Hyssop

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

Succession Planting Hyssop

3
successive plantings in your 194-day season

Sow every 8 weeks. Last sowing by Jul 28 to harvest before frost.

Plant 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 566 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Hyssop

Hyssop 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 Hyssop 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.

Hyssop 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.

Hyssop needs ~1,280 GDD — county provides 3,104 GDD Excellent fit

Hyssop Planting Timeline — Sierra County, NM

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors April 22 Apr 22 – May 6
Harvest July 1 Jul 1 – Sep 2

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

194 days in Sierra County

Growing Tips for Hyssop in Sierra County

Direct sow Hyssop outdoors after April 15 in Sierra County when soil has warmed and frost danger has passed.

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

Sierra County receives only 17" of rain annually. Hyssop needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors or direct sow in spring. Prune back in early spring to encourage bushy growth. Hyssop is drought-tolerant once established and thrives in poor soil.

Companion Planting

Good Companions

Avoid Planting Near

  • Radish

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hyssop in Sierra County, NM?

Sierra County is in Zone 8a with an average last frost of April 15. Plan your Hyssop 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 24-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.

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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 Sierra 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.