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When to Plant Kohlrabi in Alexandria City, VA

Alexandria City, Virginia Zone 8a May

This month in Alexandria City, Virginia

Here's what deserves your attention in Alexandria City, Virginia this month. Everything below is tailored to Zone 8a and timed around your local frost dates.

Avg. last frost April 6
Avg. first frost November 8
Soil temp (4") 68°F
Watering Moderate
Pest pressure Moderate
Daylight 14.1 hrs
  1. Sow kohlrabi in trays indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Start harvesting kohlrabi

    If you can't use it all right away, check the food-preservation section of your planner.

A few tasks this May that'll pay off in June
  • First harvests: kohlrabi

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Kohlrabi is an unusual brassica that forms a swollen stem above ground with a mild, sweet turnip-like flavor. Both the bulb and tender leaves are edible.

Alexandria City, Virginia is in USDA Zone 8a. The average last spring frost is April 6 and the first fall frost is November 8, giving you a growing season of approximately 216 days.

At an elevation of 738 feet, Alexandria City receives approximately 45.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Kohlrabi during the growing season.

Alexandria City, VA (Zone 8a) Long season
216 days
Last Spring Frost April 6
216 growing days
First Fall Frost November 8
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Alexandria City Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (127 days to spare)
Start indoors: Feb 20 Transplant: Mar 27 🍅 Harvest: May 15 – Jun 19
Recommended (50%) ✓ Fits season (132 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: May 25 – Jun 29
Safe Start (90%) ✓ Fits season (141 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 16 – Jul 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 Alexandria City

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

Soil pH

Your soil pH (5.8–6.8) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Alexandria City is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Kohlrabi.

How to Plant Kohlrabi

0.5"
Planting Depth
4"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Kohlrabi

5
successive plantings in your 216-day season

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

For a dedicated fall crop, sow by Aug 30.

Plant Water Budget

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

Monthly Watering Guide for Kohlrabi

Kohlrabi needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Kohlrabi Needs Rainfall You Supplement Action
Jan 4.3" 0" ❄️ Dormant
Feb 3.4" 0" ❄️ Dormant
Mar 4.8" 0" ❄️ Dormant
Apr 3" 3.8" 0" ✅ Rainfall sufficient
May 3" 3.7" 0" ✅ Rainfall sufficient
Jun 3" 3.7" 0" ✅ Rainfall sufficient
Jul 3" 4.9" 0" ✅ Rainfall sufficient
Aug 3" 3.8" 0" ✅ Rainfall sufficient
Sep 3" 3.4" 0" ✅ Rainfall sufficient
Oct 3" 2.6" 0.4" 💧 Light watering
Nov 3" 3.4" 0" ✅ Rainfall sufficient
Dec 4" 0" ❄️ Dormant

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

Kohlrabi 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.

Kohlrabi needs ~1,004 GDD — county provides 3,942 GDD Excellent fit

Kohlrabi Planting Timeline — Alexandria City, VA

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow March 23 Mar 23 – Apr 13
Harvest May 25 May 25 – Jun 29
Fall Sowing August 30 Aug 30 – Sep 13

Plant 0.5" deep · 4" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

216 days in Alexandria City

Growing Tips for Kohlrabi in Alexandria City

Direct sow Kohlrabi outdoors after April 06 in Alexandria City when soil has warmed and frost danger has passed.

Your generous 216.0-day season in Alexandria City allows multiple plantings of Kohlrabi. Sow every 22.0 days for continuous harvest.

Common pests for Kohlrabi in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Harvest when bulbs are 2-3 inches in diameter for best texture and flavor. Larger bulbs may become woody and fibrous.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kohlrabi in Alexandria City, VA?

Alexandria City is in Zone 8a with an average last frost of April 6. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Alexandria City, VA?

Alexandria City, Virginia is in USDA Hardiness Zone 8a. The average last spring frost is April 6 and first fall frost is November 8.

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Your Alexandria City Garden Planner — Free

A 24-page printable planner built for Alexandria City (Zone 8a). 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 Alexandria City, 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.