

As soon as it has usable leaves.
Once the plants are flowering, pick a few leaves and taste them. If they're woody, pick the rest of the flowers and toss the plants on the compost pile. Otherwise, harvest the best tender leaves and flower stalks before discarding the plants.
Flowers are edible and can be harvested and taste best right before they open.
A. Cutting at the base will keep the head in tact, and will be a one-time harvest.
B. 'Cut-and-come-again:' bok choy leaves can be harvested like Swiss chard by cutting roughly 2 inches from the base. Should be able to have 2-3 cuttings before the plant starts to flower.

If cut at the base, baby heads: 2 per bunch
and full size: one head
For loose leaves: add baby leaves to salad mixes
and full size leaves can be sold with 5-9 stems per bunch.

White leaf spot is a fungal disease common to Brassicas. remove any diseased plants immediately to prevent disease spread and build-up in the planting location. When present, avoid overhead sprinkler irrigation if possible as this causes water-splash spread which makes the disease worse. Only work in garden beds when leaves are dry to prevent spread of disease through contact with hands, tools or clothing.

Flea beetles will feed on the leaves which may cause the harvest to be unmarketable. Use row covering protect plants from egg-laying adults.
