Why tomatoes want 60cm of breathing room

Tomato canopies trap humidity. In a closed greenhouse, relative humidity above 80% sustained for six hours invites Botrytis cinerea and powdery mildew.

We recommend 60cm centre-to-centre for indeterminate varieties grown vertically. For Roma and other compact determinate cultivars, 45cm is the floor.

Pair tight spacing with active dehumidification or scheduled venting during the dawn humidity peak between 04:00 and 07:00.