I want to report the result of my test using mustard cover crop against root knot nematode in carrot beds. Last year I planted mustard seeds as recommended around end of June and let them grow for about 2 month until flowering stage. After that I chopped the plants with weed wacker and dug them in the soil, watered and covered with clear plastic. So I had (I hopped) 3 ways to kill nematodes - trap in the mustard roots(they can't get out), fumigate with gas, that crashed mustard produces and also solarize the soil for at least one hot month. This year I planted carrots in the same spot. The results were not that excellent as I hopped. For about 15 carrots I took out so far, at least 3 were very deformed, and additional 3-4 were strait, but had some galls at the roots at the very end of the carrot. So nematodes are still there(sigh). But I am able to get some reasonable crop(for home garden I do not care much about the shape and appearance) anyway. So even if I promised myself it will be my last attempt to grow carrots if nematodes are still there, I decided to do more research. The KRN resistant carrot seeds are still in development, so my next attempt could be marigolds or beneficial nematodes. It was a post here recommended beneficial nematodes against KRN. I see one particular site that sells them(SF nematodes) and climes they are 100% successful against KRN. However, all other sites I can find selling the same type of beneficial nematodes do not even mention KRN in a long list of pets they treat. Did anybody tried them in their gardens? What was the results?