Bok choy thrives when the weather is cool and the days are short. Plant bok choy in the fall in areas with mild, frost-free winters and hot summers. In climates where summers are cool and wet, plant bok choy in the spring as soon as the last frost has passed. Bok choy are ready to harvest 40 to 60 days after sowing; be sure to harvest the heads before they go to seed.
Take a sharp knife and a basket or bag with you to the garden.
Grasp the top of a bok choy plant gently with one hand to support the plant. Slide your knife through the stem at ground level. Be careful not to damage the outside leaves during harvest.
Trim off any yellowing or slimy leaves before placing the bok choy into your basket or bag. Store the harvest in in the refrigerator at about 32 degrees Fahrenheit. A humidity controlled vegetable crisper is ideal. Bok choy stores well for about three weeks after harvesting.