Zone-Specific Guide
Grow Choy Sum in Zone 4a
Your complete guide to growing choy sum in USDA Hardiness Zone 4a — planting windows, care tips, and harvest timing.
Spring/Fall
🌡️ Zone 4a
Days to Harvest
35–50
Spacing
6–10"
Method
Direct sow
Season
Spring/Fall
When to Plant Choy Sum in Zone 4a
Start Indoors
Mar 1 – Apr 1, Jul 1 – Aug 1
Transplant Outdoors
May 1 – Jun 1, Aug 1 – Sept 1
Direct Sow
Apr 15 – Jun, Aug – Sept
How to Grow Choy Sum in Zone 4a
📋 Key Timing Note
Spring and fall windows. Fall planting often produces better heads — less pest pressure.
Direct sow seeds between Apr 15 – Jun, Aug – Sept. Space plants 6–10" apart. Expect to harvest in approximately 35–50 days.
Common Pests in Zone 4a
Watch for these pests when growing choy sum in your area.
Frequently Asked Questions
When should I plant Choy Sum in Zone 4a?
Start seeds indoors Mar 1 – Apr 1, Jul 1 – Aug 1. Transplant outdoors May 1 – Jun 1, Aug 1 – Sept 1.
How far apart should I plant Choy Sum in Zone 4a?
Space choy sum plants 6–10" apart in Zone 4a. This gives them adequate room for airflow and root development.
What pests affect Choy Sum in Zone 4a?
Common pests for choy sum in Zone 4a include flea beetles, aphids. Use companion planting and row covers as first-line defense.
How long until Choy Sum is ready to harvest in Zone 4a?
In Zone 4a, expect choy sum to be ready in approximately 35–50 days from planting. Spring and fall windows. Fall planting often produces better heads — less pest pressure.