The products can be mixed together before planting, but tests have shown that IdaGold will bolt and flower first, only to be taken over by Pacific Gold. Brown doesn’t recommend mixing Mighty Mustard with other cover crops.
In at least one case, Pacific Gold was planted in a mixture with rye, and most of the rye was killed by the mustard’s natural systemic herbicide— also known as an allelochemical.
Mustards repel most pests because they can’t tolerate the plants’ natural heat, Brown says. But flea beetles and cabbage aphids are attracted to Mighty Mustard plants.