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When to Plant Asparagus in Mower County, MN

Mower County, Minnesota Zone 4b May

May to-do list for Mower County, Minnesota

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 28
Avg. first frost October 7
Soil temp (4") 53°F
Watering Moderate
Pest pressure Low
Daylight 14.5 hrs
  1. Set out asparagus seedlings

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

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Asparagus is a long-lived perennial vegetable that produces tender spears each spring for 15-20 years once established. It requires patience but rewards with reliable harvests.

Mower County, Minnesota is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 7, giving you a growing season of approximately 162 days.

At an elevation of 577 feet, Mower County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Asparagus to ensure they mature before fall.

Mower County, MN (Zone 4b) Moderate season
162 days
Last Spring Frost April 28
162 growing days
First Fall Frost October 7

Mower County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 8
Recommended (50%) ✓ Fits season
Transplant: May 12
Safe Start (90%) ✓ Fits season
Transplant: May 28

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 Mower County

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

Soil pH

Your soil pH (6.3–6.7) overlaps with Asparagus's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Asparagus

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Asparagus

Asparagus needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Asparagus Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3.5" 3.7" 0" ✅ Rainfall sufficient
May 3.5" 3.4" 0.1" 💧 Light watering
Jun 3.5" 3.9" 0" ✅ Rainfall sufficient
Jul 3.5" 3.3" 0.2" 💧 Light watering
Aug 3.5" 3.6" 0" ✅ Rainfall sufficient
Sep 3.5" 2.8" 0.7" 💧 Light watering
Oct 3.5" 2.4" 1.1" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

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

Asparagus 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.

Asparagus needs ~10,494 GDD — county provides 1,863 GDD May not mature

Asparagus Planting Timeline — Mower County, MN

Asparagus Planting Calendar

Activity When Date Range
Transplant Outdoors May 12 May 12 – May 26

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

730–1095 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

162 days in Mower County

Growing Tips for Asparagus in Mower County

Direct sow Asparagus outdoors after April 28 in Mower County when soil has warmed and frost danger has passed.

Your 162.0-day growing season in Mower County is tight for Asparagus (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant crowns in deep trenches with compost. Do not harvest spears for the first two years to allow root establishment. Mulch heavily to suppress weeds and retain moisture.

Companion Planting

Good Companions

Avoid Planting Near

  • Garlic
  • Onion

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Asparagus in Mower County, MN?

Mower County is in Zone 4b with an average last frost of April 28. Plan your Asparagus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mower County, MN?

Mower County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 7.

🌱

Your Mower County Garden Planner — Free

A 24-page printable planner built for Mower County (Zone 4b). 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 Mower 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.