At least 1 m²11 ft². If your bed is smaller, the planner grays this plant team out, says why, and offers the nearest adaptation that fits. It never swaps in something else without telling you.
What it looks like planted
3 × Cabbage
8 × Thyme
The real placement on an example 4 ft bed, the same layout the planner draws.
Between seasons
Living perennials stay in the bed between seasons, so only part of the ground gets rotated.
What it claims
Less cabbage-worm damage has been reported, and the reason isn't known yet
How it works: Unresolved, and we don't pick one. Two explanations have been proposed. The herbs' volatile oils (their scent) may mask the cues pests use to find the host plant, or they may disrupt the pests' landing. The trials that report an effect measured damage, which can't separate fewer eggs laid from fewer larvae surviving or more predators arriving. So no mechanism here is established; there are only candidates.
Evidence: checked against 1 source in the research-based literature.
