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When to plant Kai Lan in Aroostook County, ME

Aim to plant Kai Lan in Aroostook County on or after May 11; the window stays open through June 1. Aroostook County's 129-day frost-free season gives you just enough for one full spring planting. A second sowing from July 2 to July 16 extends the harvest into fall.

When to Plant Kai Lan in Aroostook County, ME

Aroostook County, Maine Zone 4a June

Your June planting checklist for Aroostook County, Maine

Here's what deserves your attention in Aroostook County, Maine this month. Everything below is tailored to Zone 4a and timed around your local frost dates.

Avg. last frost May 18
Avg. first frost September 24
Soil temp (4") 61°F
Watering Moderate
Pest pressure Moderate
Daylight 15.6 hrs

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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.

Aroostook County, Maine is in USDA Zone 4a. The average last spring frost is May 18 and the first fall frost is September 24, giving you a growing season of approximately 129 days.

At an elevation of 314 feet, Aroostook County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Kai Lan to ensure they mature before fall.

Aroostook County, ME (Zone 4a) Short season
129 days
Last Spring Frost May 18
129 growing days
First Fall Frost September 24

Aroostook County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.3

Drainage

Well Drained

Kai Lan Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Jun 30 – Jul 28
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Jul 6 – Aug 3
Safe Start (90%) ✓ Fits season (49 days to spare)
Start indoors: Apr 20 Transplant: Jun 1 🍅 Harvest: Jul 20 – Aug 17

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 Aroostook County

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

Soil pH

Your soil pH (4.9–6.3) is more acidic than Kai Lan prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). 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 12 weeks before your first frost date for a fall harvest.

Succession Planting Kai Lan

3
successive plantings in your 129-day season

Sow every 5.1 weeks. Last sowing by Jul 26 to harvest before frost.

For a dedicated fall crop, sow by Jul 02.

Kai Lan Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/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 2.8" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 3.3" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 3.6" 0.7" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.9" 0.4" 💧 Light watering
Oct 3.2" 0" ❄️ Dormant
Nov 2.9" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Aroostook 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 ~446 GDD — county provides 1,096 GDD Excellent fit

Kai Lan Planting Timeline — Aroostook County, ME

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 11 May 11 – Jun 1
Harvest July 6 Jul 6 – Aug 3
Fall Sowing July 2 Jul 2 – Jul 16

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

Month-by-Month Timeline

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

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: too_acidic

🗺️ USDA Zone

Zone 4a

📆 Growing Season

129 days in Aroostook County

Growing Tips for Kai Lan in Aroostook County

Direct sow Kai Lan outdoors after May 18 in Aroostook County when soil has warmed and frost danger has passed.

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 Aroostook County, ME?

Aroostook County is in Zone 4a with an average last frost of May 18. Plan your Kai Lan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Aroostook County, ME?

Aroostook County, Maine is in USDA Hardiness Zone 4a. The average last spring frost is May 18 and first fall frost is September 24.

When should I plant Kai Lan in Aroostook County, ME?

In Aroostook County, ME, plant Kai Lan after the last frost (around May 18) and before the first frost (around September 24). Best results when soil holds above 50°F.

What growing zone is Aroostook County, ME for Kai Lan?

Aroostook County sits in USDA Zone 4a. Kai Lan grows reliably in zones 2a through 11b, so it's a good fit here.

Can Kai Lan grow in Aroostook County's climate?

Yes — Kai Lan grows well in Aroostook County's temperate climate. Aroostook County averages a 129-day frost-free season, with last frost around May 18 and first frost around September 24.

🌱

Your Aroostook County Garden Planner — Free

A 22-page printable planner built for Aroostook County (Zone 4a). 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 Aroostook County, ME. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.