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When to Plant Ageratum in Elko County, NV

Elko County, Nevada Zone 5b July

What to do in July

Welcome to July in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost June 5
Avg. first frost September 15
Soil temp (4") 62°F
Watering High
Pest pressure High
Daylight 14.7 hrs
  1. Begin indoor sowing: ageratum

    You're about 10 weeks out from your last frost — the perfect window to get these germinating indoors.

Get ahead of August
  • First harvests: ageratum

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Ageratum (Ageratum houstonianum), the floss flower, produces clusters of fluffy, powder-puff blooms in the rare sky-blue and lavender tones difficult to find among warm-season annuals. Compact mounding habit makes it ideal as a front-of-border edging plant. Blooms from early summer through fall with minimal deadheading; heat and humidity tolerant once established.

Elko County, Nevada is in USDA Zone 5b. The average last spring frost is June 5 and the first fall frost is September 15, giving you a growing season of approximately 102 days.

At an elevation of 5,859 feet, Elko County receives approximately 15.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 92°F, providing good warmth for Ageratum during the growing season. Sandy soil warms quickly in spring — great for early planting — but Ageratum will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Ageratum successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Elko County, NV (Zone 5b) Short season
102 days
Last Spring Frost June 5
102 growing days
First Fall Frost September 15

Elko County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.5

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 7 Transplant: Jun 2 🌸 Bloom: Jul 28 – Oct 27
Recommended (50%) ✗ May not fit
Start indoors: Apr 17 Transplant: Jun 12 🌸 Bloom: Aug 7 – Nov 6
Safe Start (90%) ✗ May not fit
Start indoors: Apr 30 Transplant: Jun 25 🌸 Bloom: Aug 20 – Nov 19

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 Elko County

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

Soil pH

Your soil pH (7.2–8.5) is more alkaline than Ageratum prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Ageratum.

Organic Matter

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

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 739 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Ageratum

Ageratum needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Ageratum Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 0.9" 0" ❄️ Dormant
Apr 0.5" 0" ❄️ Dormant
May 0.3" 0" ❄️ Dormant
Jun 4.3" 0.4" 3.9" 🚿 Regular watering
Jul 4.3" 2.7" 1.6" 💧 Light watering
Aug 4.3" 3.1" 1.2" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 1.5" 0" ❄️ Dormant
Nov 0.7" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Ageratum 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.

Ageratum needs ~1,282 GDD — county provides 1,938 GDD Excellent fit

Ageratum Planting Timeline — Elko County, NV

Ageratum Planting Calendar

Activity When Date Range
Start Indoors April 17 Apr 17 – May 1
Transplant Outdoors June 12 Jun 12 – Jun 26
Direct Sow June 12 Jun 12 – Jul 3
Bloom August 7 Aug 7 – Nov 6

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

102 days in Elko County

Growing Tips for Ageratum in Elko County

Direct sow Ageratum outdoors after June 05 in Elko County when soil has warmed and frost danger has passed.

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

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

Elko County receives only 15" of rain annually. Ageratum needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 6–8 weeks before last frost — do not cover seed; it needs light to germinate. Can be direct-sown after last frost once soil warms to 60°F. Transplant or thin to proper spacing after frost danger passes. Deadheading isn't strictly required but tidying spent clusters improves appearance. Provide consistent moisture; drought causes premature setting. Avoid deep shade — blooms best in full sun to light afternoon shade.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Ageratum in Elko County, NV?

Elko County is in Zone 5b with an average last frost of June 5. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Elko County, NV?

Elko County, Nevada is in USDA Hardiness Zone 5b. The average last spring frost is June 5 and first fall frost is September 15.

🌱

Your Elko County Garden Planner — Free

A 22-page printable planner built for Elko County (Zone 5b). 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 Elko County, NV. Local conditions may vary. Last updated: July 2026.

Sources & credits

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