Blog

When to Plant Kai Lan in Johnston County, NC

Johnston County, North Carolina Zone 8a May

Top priorities for Johnston County, North Carolina gardeners in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 3
Avg. first frost November 3
Soil temp (4") 66°F
Watering Moderate
Pest pressure Moderate
Daylight 13.9 hrs
  1. Start kai lan under lights

    Label every cell. You will absolutely forget which is which otherwise.

  2. Harvest kai lan as they ripen

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

June prep starts now
  • First harvests: kai lan

Instant PDF download. No spam, unsubscribe any time.

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.

Johnston County, North Carolina is in USDA Zone 8a. The average last spring frost is April 3 and the first fall frost is November 3, giving you a growing season of approximately 214 days.

At an elevation of 1,120 feet, Johnston County receives approximately 49.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 92°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.

Johnston County, NC (Zone 8a) Long season
214 days
Last Spring Frost April 3
214 growing days
First Fall Frost November 3
Share this guide:

Johnston County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (137 days to spare)
Start indoors: Feb 20 Transplant: Mar 27 🍅 Harvest: May 15 – Jun 12
Recommended (50%) ✓ Fits season (137 days to spare)
Start indoors: Feb 27 Transplant: Apr 3 🍅 Harvest: May 22 – Jun 19
Safe Start (90%) ✓ Fits season (126 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 16 – Jul 14

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 Johnston County

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

Soil pH

Your soil pH (5.6–6.7) overlaps with Kai Lan's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Kai Lan.

Organic Matter

Organic matter is moderate (2.6%). 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

5
successive plantings in your 214-day season

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

For a dedicated fall crop, sow by Aug 25.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 4.4" 0" ❄️ Dormant
Feb 4.4" 0" ❄️ Dormant
Mar 5.3" 0" ❄️ Dormant
Apr 4.3" 4.1" 0.2" 💧 Light watering
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 4.2" 0.1" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 4.3" 3.9" 0.4" 💧 Light watering
Dec 4.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Johnston 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 ~998 GDD — county provides 4,066 GDD Excellent fit

Kai Lan Planting Timeline — Johnston County, NC

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors April 3 Apr 3 – Apr 17
Direct Sow March 20 Mar 20 – Apr 10
Harvest May 22 May 22 – Jun 19
Fall Sowing August 25 Aug 25 – Sep 8

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July
August Fall Sowing
September Fall Sowing
October
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

214 days in Johnston County

Growing Tips for Kai Lan in Johnston County

Direct sow Kai Lan outdoors after April 03 in Johnston County when soil has warmed and frost danger has passed.

With Johnston County's clay soil (34% clay), work in 3-4 inches of compost before planting Kai Lan. Avoid tilling when soil is wet to prevent compaction.

Your generous 214.0-day season in Johnston 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 Johnston County, NC?

Johnston County is in Zone 8a with an average last frost of April 3. Plan your Kai Lan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Johnston County, NC?

Johnston County, North Carolina is in USDA Hardiness Zone 8a. The average last spring frost is April 3 and first fall frost is November 3.

🌱

Your Johnston County Garden Planner — Free

A 24-page printable planner built for Johnston County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Johnston 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.