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When to Plant Yarrow in Humboldt County, NV

Humboldt County, Nevada Zone 6b July

Top priorities for Humboldt County, Nevada gardeners in July

Welcome to July in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 30
Avg. first frost September 15
Soil temp (4") 60°F
Watering High
Pest pressure High
Daylight 14.7 hrs
August prep starts now
  • Starting indoors: yarrow
  • First harvests: yarrow

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Achillea millefolium (Yarrow) is a tough, drought-tolerant native perennial with aromatic finely-divided foliage and broad flat-topped flower clusters that serve as a landing platform for hundreds of beneficial insect species. Available in white (the species type) and a wide range of cultivars spanning yellow, gold, pink, salmon, and deep red. Spreads by rhizome to form ground-covering colonies; blooms from late spring through midsummer with reblooming into fall if deadheaded. Exceptional in hot, dry sites where other perennials fail.

Humboldt County, Nevada is in USDA Zone 6b. The average last spring frost is May 30 and the first fall frost is September 15, giving you a growing season of approximately 108 days.

At an elevation of 5,527 feet, Humboldt County receives approximately 8.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94°F, providing good warmth for Yarrow during the growing season. Sandy soil warms quickly in spring — great for early planting — but Yarrow will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Yarrow successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting Fragrant
Humboldt County, NV (Zone 6b) Short season
108 days
Last Spring Frost May 30
108 growing days
First Fall Frost September 15

Humboldt County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.6

Drainage

Well Drained

Yarrow Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 20 Transplant: May 29 🌸 Bloom: Aug 7 – Dec 4
Recommended (50%) ✗ May not fit
Start indoors: Mar 28 Transplant: Jun 6 🌸 Bloom: Aug 15 – Dec 12
Safe Start (90%) ✗ May not fit
Start indoors: Apr 16 Transplant: Jun 25 🌸 Bloom: Sep 3 – Dec 31

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 Humboldt County

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

Soil pH

Your soil pH (7.2–8.6) is more alkaline than Yarrow prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Yarrow.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting Yarrow.

How to Plant Yarrow

18"
Between Plants
24"
Between Rows

Succession Planting Yarrow

2
successive plantings in your 108-day season

Sow every 6.9 weeks. Last sowing by Jun 17 to harvest before frost.

Yarrow Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 382 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Yarrow

Yarrow 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 Yarrow Needs Rainfall You Supplement Action
Jan 0.6" 0" ❄️ Dormant
Feb 0.5" 0" ❄️ Dormant
Mar 0.4" 0" ❄️ Dormant
Apr 0.3" 0" ❄️ Dormant
May 2.2" 0.2" 2" 🚿 Regular watering
Jun 2.2" 0.3" 1.9" 🚿 Regular watering
Jul 2.2" 1.3" 0.9" 💧 Light watering
Aug 2.2" 1.6" 0.6" 💧 Light watering
Sep 2.2" 1.1" 1.1" 🚿 Regular watering
Oct 0.8" 0" ❄️ Dormant
Nov 0.4" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Humboldt County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Yarrow 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.

Yarrow needs ~1,538 GDD — county provides 2,214 GDD Excellent fit

Yarrow Planting Timeline — Humboldt County, NV

Yarrow Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors June 6 Jun 6 – Jun 20
Direct Sow May 30 May 30 – Jun 20
Bloom August 15 Aug 15 – Dec 12

· 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Direct Sow
June Transplant Outdoors Direct Sow
July
August Bloom
September Bloom
October Bloom
November Bloom
December Bloom

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 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

108 days in Humboldt County

Growing Tips for Yarrow in Humboldt County

Direct sow Yarrow outdoors after May 30 in Humboldt County when soil has warmed and frost danger has passed.

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

Common pests for Yarrow in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Humboldt County receives only 8" of rain annually. Yarrow 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; seeds need light for germination — press onto soil surface, do not cover. Direct sow after last frost or divide established clumps in spring or fall. Thrives in poor, well-drained soil — rich soil and high fertility cause floppy stems and reduce flower count. Avoid overwatering; excellent drought tolerance once established. Deadhead spent clusters to encourage rebloom. Divide every 2–3 years to prevent center die-out and control spread. Year 2+ plants bloom most heavily; first-year plants may produce limited flowers. Dried flowers retain color well for arrangements.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Yarrow in Humboldt County, NV?

Humboldt County is in Zone 6b with an average last frost of May 30. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.

What planting zone is Humboldt County, NV?

Humboldt County, Nevada is in USDA Hardiness Zone 6b. The average last spring frost is May 30 and first fall frost is September 15.

🌱

Your Humboldt County Garden Planner — Free

A 22-page printable planner built for Humboldt County (Zone 6b). 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 Humboldt County, NV. Local conditions may vary. Last updated: July 2026.

Sources & credits

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