Companion plants for tomatoes

Basil may help mask tomato host cues from thrips.

Penn State describes basil interplanting as host-cue masking. This does not establish improved tomato flavor, yield, or protection against all pests. Both favor sunny, well-drained sites.

Spacing: Retain mature tomato and basil spacing; no universal pair-specific distance is established.

Pests: Potential thrips mechanism, not a substitute for monitoring or integrated pest management.

Selected marigold cover crops can suppress certain nematodes before tomatoes.

UF/IFAS supports selected Tagetes cultivars grown in the future vegetable bed for at least two months before vegetables. Effects depend on nematode species, cultivar and temperature. A few adjacent flowers are not proven broad pest repellents.

Spacing: This is a preplant cover-crop strategy, not a recommendation to crowd flowers beside tomatoes.

Pests: Identify the nematode and appropriate cultivar first; susceptible marigolds can increase nematodes.

Early lettuce can be harvested as later tomatoes expand.

University of Minnesota describes relay planting: an early crop nears maturity as the later tomato planting is introduced. This is timing and space use, not a pest or growth-stimulation claim.

Spacing: Reserve mature tomato space; harvest lettuce before canopy crowding becomes substantial.

Pests: No pest-control benefit is established by this relay-planting guidance.

Tomatoes and potatoes share susceptibility to late blight.

Both host Phytophthora infestans. Infected tubers or transplants and windblown spores can introduce disease. This is shared disease risk, not chemical incompatibility.

Spacing: Preserve airflow. No safe separation distance is established; adjacent rows do not prevent airborne infection.

Pests: Use healthy planting material and monitor both crops; rotation alone does not prevent airborne late blight.