Tomato plants should generally be spaced between 24 to 36 inches (61 to 91 cm) apart to ensure good air circulation, sunlight exposure, and healthy growth, which helps reduce disease risk

. Rows should be spaced about 36 to 48 inches (90 to 120 cm) apart for optimal airflow and maintenance

. For supported plants (with stakes or cages), spacing can be a bit closer, around 18 to 24 inches (45 to 60 cm) apart, especially for indeterminate or vining types

. Determinate varieties, which are bushier, typically require spacing of about 18 to 24 inches apart

. Some gardeners recommend even wider spacing-up to 3.5 to 4.5 feet (about 42 to 54 inches) apart-to maximize plant health and yield by reducing disease and pest problems, though this uses more garden space

. In summary:

• Standard spacing: 24–36 inches apart within rows, with rows 36–48 inches apart.
• Supported plants: can be spaced closer, about 18–24 inches apart.
• Larger or vigorous varieties (e.g., beefsteak): may need up to 36–48 inches apart.
• Wider spacing (3.5–4.5 feet) can improve plant health and yield but reduces the number of plants per area.

This spacing ensures tomato plants have enough room to grow, get adequate air circulation, and reduce disease risk while maximizing fruit production