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When to Plant Zucchini in Fairfax County, VA

Fairfax County, Virginia Zone 7b May

Top priorities for Fairfax County, Virginia gardeners in May

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

Avg. last frost April 6
Avg. first frost November 3
Soil temp (4") 67°F
Watering Low
Pest pressure Moderate
Daylight 14.1 hrs
  1. Fire up the seed-starting tray: zucchini

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

To set up a strong June, finish these tasks
  • First harvests: zucchini

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Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.

Fairfax County, Virginia is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is November 3, giving you a growing season of approximately 211 days.

At an elevation of 548 feet, Fairfax County receives approximately 53 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Zucchini during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Zucchini root diseases.

Fairfax County, VA (Zone 7b) Long season
211 days
Last Spring Frost April 6
211 growing days
First Fall Frost November 3
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Fairfax County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (93 days to spare)
Start indoors: Feb 27 Transplant: Apr 10 🍅 Harvest: May 29 – Jul 24
Recommended (50%) ✓ Fits season (92 days to spare)
Start indoors: Mar 9 Transplant: Apr 20 🍅 Harvest: Jun 8 – Aug 3
Safe Start (90%) ✓ Fits season (93 days to spare)
Start indoors: Mar 28 Transplant: May 9 🍅 Harvest: Jun 27 – Aug 22

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 Fairfax County

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

Soil pH

Your soil pH (5.4–6.5) is more acidic than Zucchini prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Zucchini.

How to Plant Zucchini

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

Succession Planting Zucchini

5
successive plantings in your 211-day season

Sow every 5.1 weeks. Last sowing by Sep 04 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
1.1″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 272 gal / 100 sq ft

Monthly Watering Guide for Zucchini

Zucchini needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Zucchini Needs Rainfall You Supplement Action
Jan 4.1" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 5.5" 0" ❄️ Dormant
Apr 5.2" 4.1" 1.1" 💧 Light watering
May 5.2" 3.8" 1.4" 💧 Light watering
Jun 5.2" 5" 0.2" 💧 Light watering
Jul 5.2" 5.9" 0" ✅ Rainfall sufficient
Aug 5.2" 4.1" 1.1" 💧 Light watering
Sep 5.2" 3.8" 1.4" 💧 Light watering
Oct 5.2" 3.3" 1.9" 💧 Light watering
Nov 5.2" 4.4" 0.8" 💧 Light watering
Dec 4.4" 0" ❄️ Dormant

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

Zucchini 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.

Zucchini needs ~1,037 GDD — county provides 4,167 GDD Excellent fit

Zucchini Planting Timeline — Fairfax County, VA

Zucchini Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors April 20 Apr 20 – May 4
Direct Sow April 13 Apr 13 – May 4
Harvest June 8 Jun 8 – Aug 3

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · Only during dry spells

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7b

📆 Growing Season

211 days in Fairfax County

Growing Tips for Zucchini in Fairfax County

Direct sow Zucchini outdoors after April 06 in Fairfax County when soil has warmed and frost danger has passed.

Your generous 211.0-day season in Fairfax County allows multiple plantings of Zucchini. Sow every 22.0 days for continuous harvest.

Common pests for Zucchini in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zucchini in Fairfax County, VA?

Fairfax County is in Zone 7b with an average last frost of April 6. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fairfax County, VA?

Fairfax County, Virginia is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is November 3.

🌱

Your Fairfax County Garden Planner — Free

A 24-page printable planner built for Fairfax County (Zone 7b). 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 Fairfax County, VA. 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.