Sow thistle grows with lettuce in one example of shallow/deep rooting
symbiosis. Their roots do not compete with each other.Insect and pest control—At least 2 elements are
important in companion planting for insect control. First
is the use of older plants with well-developed aroma and
essential oil accumulations. You want the insects to
know the plant is there. Second, it is important to use a
large variety of herbs. Five di5erent herbs help
discourage the cabbageworm butter'y, although one
herb may work better than another in your area. Testing
several herbs will help you determine the ones that work