https://spudsmart.com/mustering-mustard-potato-productivity/ Last year I planted Nemagon mustard in a small area, for a cover crop. The first test was to see if it would grow overwinter, as a green manure cover crop. It did. I planted it in mid December. I am zone 8a or 8b. By April, it had grown very dense, and was blooming in May. The mustard is most beneficial if you chop it and till it in while blooming. Later, I planted squashes there. I didn't expect a difference, and didn't see any. It's tomatoes, peppers, potatoes that I am most concerned about. I think there is good science behind using nematocidal mustards to reduce the nematode pest load. It's recommended as a cover crop on potato farms, to suppress potato early dying complex (PED). PED is mainly caused by the joint effects of Verticillium fungal pathogen species and root-lesion nematode species. (link) The whole article is very interesting. Rainy day reading. More from the link... "all the plants in the brassica family – such as canola, mustard, broccoli and cabbage – contain chemicals called glucosinolates. When the glucosinolates in the plant tissues break down in the soil, they are converted into gaseous compounds called isothiocyanates. Research has shown isothiocyanates are able to suppress or kill Verticillium fungi and root-lesion nematodes." But the Nemagon mustard was developed for higher levels of glucosinolates. More... "Mustards can also reduce various other soil-borne pathogens and insect pests through their isothiocyanate effect and/or through other brassica mechanisms, such as emitting compounds from their roots that suppress or kill such organisms" I figure, since my space is limited, I want to do everything I can to reduce soil-borne diseases and pests. This winter, most of my beds wont be in use for growing a crop. I usually mulch them with leaves. I decided, this year, I'll grow a cover crop of nemagon mustard and then chop it / till it in a week or two or three before planting my Spring crop. That will increase soil organic matter and, who knows? Maybe reduce soil borne diseases and pests? I want to think so, anyway. It's not exactly what the potato farmers are doing, but similar and maybe it will help keep the soil healthier. I will plant the mustard where, next year, there will be tomatoes and peppers. Maybe for potatoes too, although potatoes are planted much earlier. I wanted to grow nematocidal marigolds, but their prime growing season is the same as most garden crops, so it's more challenging. I still want to grow them separately and at least till them in where the schedule works out. I sort of did that with one bed already, but with French marigolds. Info from Canada https://www2.gnb.ca/content/dam/gnb/Departments/10/pdf/Agriculture/GrowingMustardBiofumigation.pdf Info from Australia. https://www.abc.net.au/gardening/how-to/nematodes/9429726 I ordered a pound of seeds, online. They should be here in a week or two.