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When to Plant Lilies in Knox County, OH

Knox County, Ohio Zone 6a June

June to-do list for Knox County, Ohio

A quick June briefing for Knox County, Ohio gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 29
Avg. first frost October 15
Soil temp (4") 68°F
Watering Moderate
Pest pressure High
Daylight 14.9 hrs
July will be here before you know it — start on
  • First harvests: lilies

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Lilies (Lilium spp.) are among the most impressive summer-blooming bulbs, delivering bold, upward- or outward-facing trumpet blooms on tall stems from June through August. Asiatic hybrids are the most cold-hardy, earliest to bloom, and easiest to grow; Oriental hybrids bloom later with intensely fragrant, larger flowers. Orienpet (OT) hybrids combine the hardiness of Asiatics with the fragrance and size of Orientals. True lilies (not to be confused with daylilies, which are Hemerocallis) form scaly bulbs that persist and multiply underground, returning reliably each year with increasingly large clumps.

Knox County, Ohio is in USDA Zone 6a. The average last spring frost is April 29 and the first fall frost is October 15, giving you a growing season of approximately 169 days.

At an elevation of 861 feet, Knox County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Lilies during the growing season.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Knox County, OH (Zone 6a) Moderate season
169 days
Last Spring Frost April 29
169 growing days
First Fall Frost October 15

Knox County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Lilies Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 3 🌸 Bloom: Jul 12 – Oct 18
Recommended (50%) ✗ May not fit
Transplant: May 6 🌸 Bloom: Jul 15 – Oct 21
Safe Start (90%) ✗ May not fit
Transplant: May 23 🌸 Bloom: Aug 1 – Nov 7

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 Knox County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Lilies's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Lilies.

Organic Matter

Organic matter is excellent (4.1%) — Lilies will thrive.

How to Plant Lilies

5"
Planting Depth
12"
Between Plants
18"
Between Rows

Succession Planting Lilies

2
successive plantings in your 169-day season

Sow every 8 weeks. Last sowing by Jun 17 to harvest before frost.

Lilies Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 722 gal / 100 sq ft

Monthly Watering Guide for Lilies

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

Month Lilies Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.2" 1.1" 💧 Light watering
Sep 4.3" 2.7" 1.6" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

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

Lilies 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.

Lilies needs ~1,449 GDD — county provides 2,577 GDD Excellent fit

Lilies Planting Timeline — Knox County, OH

Lilies Planting Calendar

Activity When Date Range
Transplant Outdoors May 6 May 6 – May 20
Bloom July 15 Jul 15 – Oct 21

Plant 5" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–120 days

🧪 Soil pH

Needs 6–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

169 days in Knox County

Growing Tips for Lilies in Knox County

Direct sow Lilies outdoors after April 29 in Knox County when soil has warmed and frost danger has passed.

General growing tips

Plant bulbs in fall (preferred, September–October) or spring, setting them 3 times their diameter deep (typically 4–6 inches) with the pointed end up. Lilies need excellent drainage — they will rot in wet or heavy clay soils. Site with full sun on stems and blooms but cool, shaded soil at the base (ground cover or shallow-rooted annuals at their feet is ideal). Remove spent blooms but leave stems and foliage until they yellow naturally, as the bulb needs the foliage to photosynthesize and rebuild energy stores. Red lily beetle is a serious pest in the Northeast and Pacific Northwest; inspect plants regularly and hand-pick adults and larvae. Never plant Oriental or Asiatic lilies near cats — all Lilium species are highly toxic to cats. Year 2+ bulbs produce the most stems and largest blooms.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lilies in Knox County, OH?

Knox County is in Zone 6a with an average last frost of April 29. Plan your Lilies planting based on this frost date — see the calendar above for exact timing.

What planting zone is Knox County, OH?

Knox County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 29 and first fall frost is October 15.

🌱

Your Knox County Garden Planner — Free

A 22-page printable planner built for Knox County (Zone 6a). 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 Knox County, OH. Local conditions may vary. Last updated: June 2026.

Sources & credits

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