Alfalfa is also a good choice for a rotational crop because its frequent cutting cycle reduces many weeds, and herbicides available to use on this crop eliminate most other weeds. Other crops considered as useful rotational crops with tomatoes include wheat, cotton, rice, dry beans, onions, carrots, and safflower. Rotational crops that are not recommended include potatoes, peppers, and eggplant because they are genetically similar, and all but potatoes have similar cultural practices. Similar herbicides are used in these solanaceous crops, which often result in common uncontrolled weeds. For the same reasons, mono cropping tomatoes is also not recommended.
Soil solarization can provide control of many soilborne diseases, nematodes, and weed pests.
Avoid moving weed seeds into fields on equipment. When equipment has been used in a weedy field, clean it before entering other fields. Once dodder attaches to the tomato plant, it does not require connection with the soil and cannot be selectively controlled with cultivation. To reduce dodder problems, control broadleaf weeds that act as alternate hosts for dodder, allowing it to spread onto tomatoes. At thinning, eliminate tomato plants that have dodder attached to help reduce the spread of this weed.