Zone 4 · Leafy Greens Growing Guide

When to Plant Bok Choy
in Zone 4

Fast, productive, and delicious stir-fried or in soups. Baby bok choy can be harvested whole at 30 days or left to mature as full heads. Cool-season crop that tolerates light frost.

Plant outdoors
Apr 15 – Jun 10, Aug 10 – Sep 1
Start indoors
Direct sow
Last Frost
~May 1
Days to harvest
45–60 days
Difficulty
Easy
Plant now — Zone 4
Harvest window: May – Jul, Sep – Oct

Planting Calendar

In Zone 4, Bok Choy should be planted outdoors Apr 15 – Jun 10, Aug 10 – Sep 1, after the average last frost date of approximately May 1.

Spring and fall crops. Sow every 2 weeks in spring for continuous harvest before heat bolts plants.

Care Guide

Sunlight
Full sun to partial shade · 3–8 hrs/day
Watering
Regular
Spacing
6–12 inches
Soil
Fertile, moisture-retentive, well-draining
Days to maturity
45–60 days
Soil pH
6.0–7.0
plant tip · Zone 4

Spring and fall crops. Sow every 2 weeks in spring for continuous harvest before heat bolts plants.

Feeding Schedule

How often
every 3 weeks
Feed type
balanced (10-10-10)
Key timing
throughout growing season

Fast-growing and a moderate feeder. Liquid balanced feed every 3 weeks. Bolts in heat regardless of feeding.

Succession Planting

Sow every 3 weeks

Sow every 3 weeks from early spring and again from late summer. Bolts in heat — time sowings to mature before temperatures exceed 75°F.

Companion Planting for Bok Choy

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

Grows well with
  • Garlic
  • Onions
  • Beets
  • Spinach
Keep away from
  • Tomatoes
  • Fennel
  • Nightshades

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 Bok Choy

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, bok choy has two planting windows: Apr 15 – Jun 10, Aug 10 – Sep 1. The spring window opens after your last frost around May 1. The fall window lets you grow a second crop before first frost around Oct 1. Spring and fall crops. Sow every 2 weeks in spring for continuous harvest before heat bolts plants.
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 bok choy include Garlic, Onions, Beets, Spinach. Avoid planting near Tomatoes, Fennel, Nightshades, which can compete for nutrients or attract pests.
Bok Choy typically takes 45–60 days from transplant or direct sow to harvest in Zone 4. Expected harvest window: May – Jul, Sep – Oct.

Free app · iOS February 2028

Track your Bok Choy 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.

Bok Choy in other zones
Crop Guides