Up to 70 days. Pak Choi is also known as Bok Choy. The plant produces large, green leaves off a thick, white stem. Leaves have a mild and peppery flavor, making them an exciting addition to many dishes. This hardy garden crop can be grown in climate zones one through nine. After around seventy days, the leaves can be harvested. They can be kept for three months after harvesting.
It is recommended to sow Pak Choi seeds indoors, and transplant them after one month, to ensure that they will thrive in their new outdoor environment. When transplanting them, put them in full or partial sun, but be sure to keep the soil moist for them. For best results, harden them off over a week-long period. They will also need to be watered often, about two inches of water for every week they grow, and thrive when there is compose added to their soil. The heads will be firm at around 70 days. They can be harvested at this point. Remove the full plant to harvest them, including the stem and the root for healthy remaining soil. Leaves can stay fresh for up to three months after they are harvested and have a mild and peppery flavor.