Blog

When to Plant Parsnip in Cass County, MN

Cass County, Minnesota Zone 4a May

May in Cass County, Minnesota — your action list

We've pulled the most time-sensitive tasks for Cass County, Minnesota this May and put them front and centre. Tackle them in order.

Avg. last frost May 12
Avg. first frost September 28
Soil temp (4") 49°F
Watering Moderate
Pest pressure Low
Daylight 14.9 hrs
  1. Put parsnip seeds straight in the ground

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

Instant PDF download. No spam, unsubscribe any time.

Parsnips are a sweet, nutty root vegetable that develops best flavor after exposure to frost. They require a long growing season but reward patient gardeners.

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 Parsnip to ensure they mature before fall.

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

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 8 🍅 Harvest: Aug 21 – Oct 2
Recommended (50%) ✗ May not fit
Transplant: May 12 🍅 Harvest: Aug 25 – Oct 6
Safe Start (90%) ✗ May not fit
Transplant: May 27 🍅 Harvest: Sep 9 – Oct 21

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 Parsnip's growing requirements.

Soil pH

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

Soil Texture

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

Organic Matter

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

How to Plant Parsnip

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 26 gal / 100 sq ft

Monthly Watering Guide for Parsnip

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

Month Parsnip 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 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
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.

Parsnip 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.

Parsnip needs ~1,150 GDD — county provides 1,390 GDD Good fit

Parsnip Planting Timeline — Cass County, MN

Parsnip Planting Calendar

Activity When Date Range
Direct Sow May 5 May 5 – May 26
Harvest August 18 Aug 18 – Sep 29
Fall Sowing July 6 Jul 6 – Jul 20

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow
June
July Fall Sowing
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

100–130 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

139 days in Cass County

Growing Tips for Parsnip in Cass County

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

Your 139.0-day growing season in Cass County is tight for Parsnip (100.0-130.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Parsnip in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Use only fresh seed as parsnip seed viability declines rapidly. Sow directly in spring in deeply worked soil. Leave roots in the ground through winter for sweetest flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Celery

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Parsnip in Cass County, MN?

Cass County is in Zone 4a with an average last frost of May 12. Plan your Parsnip 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.

🌱

Your Cass County Garden Planner — Free

A 24-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.

Instant PDF download. No spam, unsubscribe any time.

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: May 2026.

Sources & credits

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