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When to Plant Asparagus in Northumberland County, PA

Northumberland County, Pennsylvania Zone 6b May

Your May gardening checklist

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

Avg. last frost April 17
Avg. first frost October 26
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Move asparagus from tray to bed

    Frost risk is low now in Northumberland County, Pennsylvania. If you've been covering beds overnight, you can stop.

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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.

Northumberland County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 17 and the first fall frost is October 26, giving you a growing season of approximately 192 days.

At an elevation of 324 feet, Northumberland County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Asparagus during the growing season.

Northumberland County, PA (Zone 6b) Moderate season
192 days
Last Spring Frost April 17
192 growing days
First Fall Frost October 26

Northumberland County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Apr 27
Recommended (50%) ✓ Fits season
Transplant: May 1
Safe Start (90%) ✓ Fits season
Transplant: May 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 Northumberland County

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

Soil pH

Your soil pH (5.1–6.6) is more acidic than Asparagus prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Asparagus.

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 3.2" 0" ❄️ Dormant
Feb 2.8" 0" ❄️ Dormant
Mar 3.4" 0" ❄️ Dormant
Apr 3.5" 3.2" 0.3" 💧 Light watering
May 3.5" 3.8" 0" ✅ Rainfall sufficient
Jun 3.5" 4" 0" ✅ Rainfall sufficient
Jul 3.5" 3.8" 0" ✅ Rainfall sufficient
Aug 3.5" 3.4" 0.1" 💧 Light watering
Sep 3.5" 3.3" 0.2" 💧 Light watering
Oct 3.5" 3.8" 0" ✅ Rainfall sufficient
Nov 2.7" 0" ❄️ Dormant
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Northumberland 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 ~16,653 GDD — county provides 3,504 GDD May not mature

Asparagus Planting Timeline — Northumberland County, PA

Asparagus Planting Calendar

Activity When Date Range
Transplant Outdoors May 1 May 1 – May 15

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: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

192 days in Northumberland County

Growing Tips for Asparagus in Northumberland County

Direct sow Asparagus outdoors after April 17 in Northumberland County when soil has warmed and frost danger has passed.

Your 192.0-day growing season in Northumberland 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 Northumberland County, PA?

Northumberland County is in Zone 6b with an average last frost of April 17. Plan your Asparagus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Northumberland County, PA?

Northumberland County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 17 and first fall frost is October 26.

🌱

Your Northumberland County Garden Planner — Free

A 24-page printable planner built for Northumberland County (Zone 6b). 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 Northumberland County, PA. 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.