Zone 4 · Brassicas Growing Guide

When to Plant Brussels Sprouts
in Zone 4

The most patient brassica — needs cold to form tight buttons. Flavour dramatically improves after frost. Definitely a fall crop.

Plant outdoors
May 10 – Jun 1
Start indoors
Apr 1 – Apr 15
Last Frost
~May 1
Days to harvest
90–110 days
Difficulty
Hard
Start indoors — Zone 4
Harvest window: Oct – Nov

Planting Calendar

In Zone 4, Brussels Sprouts should be planted outdoors May 10 – Jun 1, after the average last frost date of approximately May 1. Start seeds indoors around Apr 1 – Apr 15 for a head start.

Harvest improves with each frost.

Care Guide

Sunlight
Full sun · 6–8 hrs/day
Watering
Regular
Spacing
18–24 inches
Soil
Rich, fertile, well-draining
Days to maturity
90–110 days
Soil pH
6.0–7.5
plant tip · Zone 4

Harvest improves with each frost.

Feeding Schedule

How often
monthly
Feed type
high nitrogen then balanced
Key timing
switch to balanced when sprouts form

Long season crop. Feed monthly. Avoid excess nitrogen late season or sprouts will be loose and leafy.

Companion Planting for Brussels Sprouts

What you plant next to brussels sprouts makes a real difference — some plants actively help, others compete or attract pests.

Grows well with
  • Celery
  • Onions
  • Hyssop
Keep away from
  • Tomatoes
  • Strawberries
  • Fennel

These guides get better when growers like you contribute. If something’s wrong or you’ve learned something worth sharing, we’d love to hear it.

What needs correcting?

What should it say?

Your zone (optional)

Thanks — we'll review this and update the guide if needed.

Your growing tip for Brussels Sprouts

Your name (optional)

Your zone (optional)

Tips are reviewed before publishing. Accepted tips earn you a Founding Grower badge when the plant app launches.

Thanks for contributing! We'll review your tip and be in touch before launch.

Common questions

In Zone 4, start brussels sprouts seeds indoors around Apr 1 – Apr 15, then transplant outdoors May 10 – Jun 1 after your last frost around May 1. Harvest improves with each frost.
Zone 4 has an average last spring frost of approximately May 1 and a first fall frost around Oct 1. These dates vary by specific location — use your ZIP code in the plant app for precision based on the nearest NOAA weather station.
Good companion crops for brussels sprouts include Celery, Onions, Hyssop. Avoid planting near Tomatoes, Strawberries, Fennel, which can compete for nutrients or attract pests.
Brussels Sprouts typically takes 90–110 days from transplant or direct sow to harvest in Zone 4. Expected harvest window: Oct – Nov.

Free app · iOS February 2028

Track your Brussels Sprouts in plant

Get a live traffic light for every crop in your garden — zone-aware planting calendar, real-time weather alerts, and a community of growers near you.

Be first to back on Kickstarter and lock in the founding price.

Brussels Sprouts in other zones
Crop Guides