Joi Choi
Bok Choy in the US

Being a cool season crop, Bok Choy does best when you sow it in spring or fall, dodging the hottest summer months. Check your USDA zone for the best spring and fall sowing times; generally, you'll start a few weeks before your last frost in spring, and again in late summer for a fall crop. You can sow seeds direct into the ground or start them indoors in trays about half an inch deep. Give them a bit of space, aiming for about 6 to 12 inches between plants once they're settled. For a steady supply, sow a small batch every two or three weeks, that's what I do.

If you've started your Bok Choy indoors, you'll want to prick out the seedlings gently into individual cells once they're big enough to handle. Before planting them out into the garden, make sure to harden them off for about a week, giving them a taste of the outdoors. Plant them out once the risk of your last frost has passed for spring crops, or when the heat of summer starts to ease for fall crops, keeping that 6 to 12-inch spacing. They're quite happy in containers too, if you're a bit short on ground space.