Selected Brassicas Diakon radish is a tillage radish with a large taproot that can penetrate compacted soil layers. It acts like a natural plough increasing soil aeration, water-holding capacity and nutrients. The taproot holds residual nutrients over winter, then decays quickly, releasing them for the following spring crop. It helps suppress weeds and works well as a single crop or as part of a mix. Swiss Chard is a leafy Brassica grown for its leaf and stems with a high nutritional content of minerals and vitamins.