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When to Plant Daylily in Pullman, WA

Whitman County, Washington Zone 6b July

July to-do list for Whitman County, Washington

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

Avg. last frost May 10
Avg. first frost September 29
Soil temp (4") 79°F
Watering Critical
Pest pressure High
Daylight 15.3 hrs
  1. Start daylily indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

To set up a strong August, finish these tasks
  • First harvests: daylily

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Hemerocallis (Daylily) is one of the most adaptable and trouble-free perennials in cultivation. Though each flower lasts only a single day, established clumps produce dozens to hundreds of buds per stem, delivering weeks of continuous color through summer. Modern hybrids extend the range from pale cream and melon through deep burgundy and purple. Nearly indestructible once established — tolerating poor soil, drought, competition, and neglect — daylilies form dense spreading clumps that effectively suppress weeds. An excellent low-maintenance choice for slopes, borders, and naturalized areas.

Pullman, Washington is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is September 29, giving you a growing season of approximately 142 days.

At an elevation of 1,541 feet, Whitman County receives approximately 14.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Daylily during the growing season. With low rainfall, drip irrigation is essential for growing Daylily successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Good for cutting
Pullman, WA (Zone 6b) Short season
142 days
Last Spring Frost May 10
142 growing days
First Fall Frost September 29

Pullman Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Daylily Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 25 Transplant: May 6 🌸 Bloom: Jul 22 – Nov 11
Recommended (50%) ✗ May not fit
Start indoors: Mar 8 Transplant: May 17 🌸 Bloom: Aug 2 – Nov 22
Safe Start (90%) ✗ May not fit
Start indoors: Apr 4 Transplant: Jun 13 🌸 Bloom: Aug 29 – Dec 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 Pullman

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

Soil pH

Your soil pH (5.5–6.7) overlaps with Daylily's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Whitman County is excellent for Daylily — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.0%) — Daylily will thrive.

How to Plant Daylily

1"
Planting Depth
24"
Between Plants
30"
Between Rows

Succession Planting Daylily

2
successive plantings in your 142-day season

Sow every 6.9 weeks. Last sowing by Jul 01 to harvest before frost.

Daylily Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 90 gal / 100 sq ft

Monthly Watering Guide for Daylily

Daylily 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 Daylily Needs Rainfall You Supplement Action
Jan 2.2" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 2.2" 0.8" 1.4" 🚿 Regular watering
Jun 2.2" 0.6" 1.6" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.2" 2" 🚿 Regular watering
Sep 2.2" 0.6" 1.6" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

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

Daylily 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.

Daylily needs ~1,200 GDD — county provides 2,272 GDD Excellent fit

Daylily Planting Timeline — Pullman, WA

Daylily Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors May 17 May 17 – May 31
Bloom August 2 Aug 2 – Nov 22

Plant 1" deep · 24" apart · Rows 30" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

142 days in Whitman County

Growing Tips for Daylily in Pullman

Direct sow Daylily outdoors after May 10 in Whitman County when soil has warmed and frost danger has passed.

Whitman County receives only 14" of rain annually. Daylily needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Daylilies are most commonly propagated by division rather than seed; cultivar seeds do not come true. Transplant bare-root or potted divisions in early spring or fall, setting crowns no more than 1 inch below soil level. If starting from seed (species types only), start indoors 8–10 weeks before last frost. Established plants are extremely drought-tolerant; moderate water during bloom period improves flower quality. Divide crowded clumps every 3–5 years in early spring or fall to maintain vigor. In warm zones (8+), some cultivars are evergreen; in cold zones, foliage dies back each fall. Year 2+ plants bloom most heavily — first-year transplants may produce limited flowers.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

🌱

Your Whitman County Garden Planner — Free

A 22-page printable planner built for Whitman 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 Whitman County, WA. Local conditions may vary. Last updated: July 2026.