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When to Plant Asparagus in Scott County, IA

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.

Scott County, Iowa is in USDA Zone 5a. The average last spring frost is April 15 and the first fall frost is October 17, giving you a growing season of approximately 185 days.

At an elevation of 678 feet, Scott County receives approximately 37.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Asparagus to ensure they mature before fall.

Scott County, IA (Zone 5a) Moderate season
185 days
Last Spring Frost April 15
185 growing days
First Fall Frost October 17

Scott County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Apr 24
Recommended (50%) ✓ Fits season
Transplant: Apr 29
Safe Start (90%) ✓ Fits season
Transplant: May 17

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 Scott County

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

Soil pH

Your soil pH (5.8โ€“6.7) is more acidic than Asparagus prefers (6.5โ€“7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Scott County is excellent for Asparagus โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.6%) โ€” 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
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

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 โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.9" 0" โ„๏ธ Dormant
Mar โ€” 2.9" 0" โ„๏ธ Dormant
Apr 3.5" 3.8" 0" โœ… Rainfall sufficient
May 3.5" 4" 0" โœ… Rainfall sufficient
Jun 3.5" 4.8" 0" โœ… Rainfall sufficient
Jul 3.5" 4.6" 0" โœ… Rainfall sufficient
Aug 3.5" 3.9" 0" โœ… Rainfall sufficient
Sep 3.5" 3" 0.5" ๐Ÿ’ง Light watering
Oct 3.5" 3" 0.5" ๐Ÿ’ง Light watering
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 2.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Scott County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~11,178 GDD — county provides 2,266 GDD May not mature

Asparagus Planting Timeline โ€” Scott County, IA

Asparagus Planting Calendar

Activity When Date Range
Transplant Outdoors April 29 Apr 29 โ€“ May 13

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

730โ€“1095 days

๐Ÿงช Soil pH

Needs 6.5โ€“7.5 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

185 days in Scott County

Growing Tips for Asparagus in Scott County

Direct sow Asparagus outdoors after April 15 in Scott County when soil has warmed and frost danger has passed.

Your 185.0-day growing season in Scott 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 Scott County, IA?

Scott County is in Zone 5a with an average last frost of April 15. Plan your Asparagus planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Scott County, IA?

Scott County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 15 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Scott County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Scott County, IA. Local conditions may vary. Last updated: April 2026.