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When to plant Daylily in Cass County, MN

Cass County's short 139-day growing season means one Daylily planting between May 26 and June 9. No fall crop in Zone 4a.

When to Plant Daylily in Cass County, MN

Cass County, Minnesota Zone 4a July

July to-do list for Cass County, Minnesota

Your garden in Cass County, Minnesota is working on a schedule, even when you're not. Here's where you should be this July.

Avg. last frost May 12
Avg. first frost September 28
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 15.3 hrs
  1. Get daylily seeds going inside

    Your window is short. These crops want several weeks of indoor growth before they go outside.

Before August arrives, get these ready
  • 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.

Cass County, Minnesota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 28, giving you a growing season of approximately 139 days.

At an elevation of 938 feet, Cass County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Daylily to ensure they mature before fall.

Perennial Blooms in Summer Pollinator-friendly Good for cutting
Cass County, MN (Zone 4a) Short season
139 days
Last Spring Frost May 12
139 growing days
First Fall Frost September 28

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Daylily Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 27 Transplant: May 22 🌸 Bloom: Aug 21 – Oct 23
Recommended (50%) ✗ May not fit
Start indoors: Mar 3 Transplant: May 26 🌸 Bloom: Aug 25 – Oct 27
Safe Start (90%) ✗ May not fit
Start indoors: Mar 18 Transplant: Jun 10 🌸 Bloom: Sep 9 – Nov 11

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 Cass County

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

Soil pH

Your soil pH (5.9–6.9) overlaps with Daylily's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — Daylily will thrive.

How to Plant Daylily

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

Succession Planting Daylily

2
successive plantings in your 139-day season

Sow every 6.9 weeks. Last sowing by Jun 30 to harvest before frost.

Daylily Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 3.9" 0" ✅ Rainfall sufficient
Jul 2.2" 3.8" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.5" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Cass 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 ~750 GDD — county provides 1,390 GDD Excellent fit

Daylily Planting Timeline — Cass County, MN

Daylily Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 – Mar 17
Transplant Outdoors May 26 May 26 – Jun 9
Bloom August 25 Aug 25 – Oct 27

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

139 days in Cass County

Growing Tips for Daylily in Cass County

Direct sow Daylily outdoors after May 12 in Cass County when soil has warmed and frost danger has passed.

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 →

Frequently Asked Questions

When should I plant Daylily in Cass County, MN?

Cass County is in Zone 4a with an average last frost of May 12. Plan your Daylily planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cass County, MN?

Cass County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 28.

When should I plant Daylily in Cass County, MN?

In Cass County, MN, plant Daylily after the last frost (around May 12) and before the first frost (around September 28). Best results when soil holds above 50°F.

What growing zone is Cass County, MN for Daylily?

Cass County sits in USDA Zone 4a. Daylily grows reliably in zones 3a through 10b, so it's a good fit here.

Can Daylily grow in Cass County's climate?

Yes — Daylily grows well in Cass County's temperate climate. Cass County averages a 139-day frost-free season, with last frost around May 12 and first frost around September 28.

🌱

Your Cass County Garden Planner — Free

A 22-page printable planner built for Cass County (Zone 4a). 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 Cass County, MN. 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.