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When to Plant Kai Lan in Onslow County, NC

Onslow County, North Carolina Zone 8b May

This month in Onslow County, North Carolina

Here's what deserves your attention in Onslow County, North Carolina this month. Everything below is tailored to Zone 8b and timed around your local frost dates.

Avg. last frost March 21
Avg. first frost November 18
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Basket week: kai lan

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Before June arrives, get these ready
  • First harvests: kai lan

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Kai lan (Chinese broccoli) is a brassica grown for its thick, glossy stems and small flower buds. It has a slightly bitter, broccoli-like flavor essential in Cantonese cooking.

Onslow County, North Carolina is in USDA Zone 8b. The average last spring frost is March 21 and the first fall frost is November 18, giving you a growing season of approximately 242 days.

At an elevation of 541 feet, Onslow County receives approximately 46.8 inches of rainfall annually with predominantly clay loam soil. Summer highs average 90°F, providing good warmth for Kai Lan during the growing season. Clay soil retains moisture well for Kai Lan, but amend with compost to improve drainage and prevent root rot.

Onslow County, NC (Zone 8b) Long season
242 days
Last Spring Frost March 21
242 growing days
First Fall Frost November 18
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Onslow County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (168 days to spare)
Start indoors: Feb 4 Transplant: Mar 11 🍅 Harvest: Apr 29 – May 27
Recommended (50%) ✓ Fits season (165 days to spare)
Start indoors: Feb 14 Transplant: Mar 21 🍅 Harvest: May 9 – Jun 6
Safe Start (90%) ✓ Fits season (161 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: May 27 – Jun 24

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 Onslow County

How your county's soil matches Kai Lan's growing requirements.

Soil pH

Your soil pH (5.5–6.2) is more acidic than Kai Lan prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The clay loam soil in Onslow County is excellent for Kai Lan — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Kai Lan.

How to Plant Kai Lan

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Kai Lan

6
successive plantings in your 242-day season

Sow every 5.1 weeks. Last sowing by Sep 19 to harvest before frost.

For a dedicated fall crop, sow by Sep 09.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 404 gal / 100 sq ft

Monthly Watering Guide for Kai Lan

Kai Lan needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Kai Lan Needs Rainfall You Supplement Action
Jan 4" 0" ❄️ Dormant
Feb 3.9" 0" ❄️ Dormant
Mar 4.3" 4.2" 0.1" 💧 Light watering
Apr 4.3" 3.1" 1.2" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 4" 0.3" 💧 Light watering
Dec 4" 0" ❄️ Dormant

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

Kai Lan 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.

Kai Lan needs ~919 GDD — county provides 4,235 GDD Excellent fit

Kai Lan Planting Timeline — Onslow County, NC

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors February 14 Feb 14 – Feb 28
Transplant Outdoors March 21 Mar 21 – Apr 4
Direct Sow March 7 Mar 7 – Mar 28
Harvest May 9 May 9 – Jun 6
Fall Sowing September 9 Sep 9 – Sep 23

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

242 days in Onslow County

Growing Tips for Kai Lan in Onslow County

Direct sow Kai Lan outdoors after March 21 in Onslow County when soil has warmed and frost danger has passed.

With Onslow County's clay soil (30% clay), work in 3-4 inches of compost before planting Kai Lan. Avoid tilling when soil is wet to prevent compaction.

Your generous 242.0-day season in Onslow County allows multiple plantings of Kai Lan. Sow every 22.0 days for continuous harvest.

Common pests for Kai Lan 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 flower buds first appear but before they open. Cut stems at the base to encourage side shoots. Prefers cool weather.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kai Lan in Onslow County, NC?

Onslow County is in Zone 8b with an average last frost of March 21. Plan your Kai Lan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Onslow County, NC?

Onslow County, North Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 21 and first fall frost is November 18.

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Your Onslow County Garden Planner — Free

A 24-page printable planner built for Onslow County (Zone 8b). 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 Onslow County, NC. 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.