When to Plant Choy Sum in Zone 4
In USDA zone 4a, plant outdoors May 1 to June 15, and expect your first harvest around June 15. Zone 4 also has a fall planting window opening around July 26. (4a shown here — see 4a and 4b dates separately below.)
Choy Sum planting calendar for USDA Zone 4a
Average last spring frost
May 15
Average first fall frost
September 20
spring planting
Direct sow
May 1
Projected first harvest
Jun 15
fall planting
Direct sow
Jul 26
Projected first harvest
Sep 9
spring planting
fall planting
Choy Sum is ready to harvest in about 45 days, needing roughly 128 frost-free days in zone 4a.
Choy Sum planting calendar for USDA Zone 4b
Average last spring frost
May 10
Average first fall frost
September 25
spring planting
Direct sow
Apr 26
Projected first harvest
Jun 10
fall planting
Direct sow
Jul 31
Projected first harvest
Sep 14
spring planting
fall planting
Choy Sum is ready to harvest in about 45 days, needing roughly 138 frost-free days in zone 4b.
Not sure whether you're in 4a or 4b? Set your ZIP in HomeSown for dates tuned to your exact location.
Varieties to grow
1 variety of choy sum in the HomeSown library. Tap any for its full grow guide.
Common problems with choy sum
What to watch for, with identification and treatment for each
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