When to Plant Kale in USDA Zone 4a
Top priorities for Zone 4a gardeners in May
May is a pivotal month for Zone 4a gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Set out kale seedlings
Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.
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Seed kale outdoors
Your soil is warming°F — warm enough for these to germinate without babying.
June will be here before you know it — start on
- Starting indoors: kale
Kale is an exceptionally hardy, nutrient-dense green available in curly, lacinato, and Russian varieties. It tolerates heavy frost and often tastes sweeter after cold exposure.
In Zone 4a, the average last spring frost is around May 6 and the first fall frost is around September 28, giving you a growing season of approximately 145 days.
Kale Planting Timeline — Zone 4a
Where Is USDA Zone 4a?
The map below highlights the states that contain Zone 4a. Click any state to see the Kale planting schedule for that location.
Kale Planting Calendar — Zone 4a
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 25 | Mar 25 – Apr 8 |
| Transplant Outdoors | May 6 | May 6 – May 20 |
| Direct Sow | April 29 | Apr 29 – May 20 |
| Harvest | July 1 | Jul 1 – Aug 26 |
| Fall Sowing | July 6 | Jul 6 – Jul 20 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Free Zone 4a Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4a with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · Moderate — regular watering
Days to Maturity
50–70 days
Soil pH
6 – 7.5
Zone Temperature Range
°F to °F average annual minimum
Growing Season
145 days (Zone average)
Planting Specifications
| Planting Depth | 1 inches |
| Plant Spacing | 15 inches apart |
| Row Spacing | 24 inches between rows |
Succession Planting Kale in Zone
Sow every 5.7 weeks for continuous harvest throughout the season.
Growing Tips for Kale in Zone
Zone has a short growing season (~145 days). Start Kale indoors early and use season-extension techniques like row covers and cold frames.
Direct sow or transplant in early spring or late summer. Harvest outer leaves first to keep plants productive. Kale overwinters in many climates and can provide greens all year.
Companion Planting
Good Companions
Avoid Planting Near
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Saving Kale Seeds
Isolate 1/2 mile from other brassicas (broccoli, cabbage, etc.) — they all cross.
Recommended for Your Garden
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Keep your garden organized with durable, weather-resistant plant labels.
Related Plants
Kale in Other Zones
Kale by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Kale in Zone 4a?
In Zone 4a, plan your Kale planting around the average last frost date of May 6. Start seeds indoors around March 25. Direct sow outdoors around April 29. Transplant seedlings around May 6.
Can Kale grow in Zone 4a?
Yes, Kale can grow well in Zone 4a, hardy in USDA zones 2a through 11b. Zone 4a has a growing season of approximately 145 days, which is sufficient for Kale (50-70 days to maturity).
When can I harvest Kale in Zone 4a?
In Zone 4a, expect to harvest Kale from July 1 – August 26. Kale takes 50-70 days from planting to harvest.
What is the last frost date for Zone 4a?
The average last spring frost in Zone 4a is around May 6, and the first fall frost is around September 28. This gives a growing season of approximately 145 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Kale?
Good companion plants for Kale include Beets, Celery, Lettuce, Onion. These companions can help with pest control, pollination, and nutrient sharing.
Your Free Printable Garden Planner
A 24-page printable planner tailored to your zone. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.