Brassica napus: Canola/rapeseed is a winter annual. Producers should plant canola between September and early October when soil temperatures are between 45 and 85 degrees Fahrenheit. Because brassicas grow rapidly and produce lots of biomass, they are good for choking out weeds. Canola/rapeseed are very good nitrogen scavengers, as well as provide very good erosion control. When brassicas decompose, they produce biotoxins that serve as deterrents for some weeds, nematodes, insects and other soil-borne pathogens.
Brassica spp., Sinapis spp.: Mustards, a member of the brassica family, usually have the highest concentration of biotoxins. Producers should plant mustards between September and early October when soil temperatures are between 45 and 85 degrees Fahrenheit. These plants are great deterrents for some pests, weeds, nematodes and other soil-borne pathogens. Mustards have a fibrous root system and a taproot that extends about 3 feet. These roots make mustards very good phosphorous and potassium scavengers.
Raphanus sativa: Radishes, winter annuals, produce large amounts of biomass. Producers should plant radishes between September and early October when soil temperatures are between 45 and 85 degrees Fahrenheit. It decomposes quickly, making nutrients readily available for the subsequent crop. Deep roots scavenge nutrients and develop channels that increase water infiltration and root penetration. Smaller radish roots extend topsoil channels. Radishes also provide excellent weed control, as well as very good compaction reduction and erosion control.
Fagopyrum esculentum: Buckwheat is a fast-growing summer annual broadleaf grain. It should be planted after the last frost. Buckwheat is an excellent cover crop for suppressing weeds and attracting beneficial insects in addition to building organic matter. It is also an excellent phosphorous and potassium scavenger.