Winter beans can certainly be sown throughout December and January and into the first week of February if conditions are suitable.
January sowings will produce later maturing crops (5-7days) when compared to an early November sowing, straw may be slightly taller and there is an increased chance of aphid attack later in the season, yields are likely to be 10-15% down on the optimum late Oct-early Nov sowings.
In 2010 trials were carried out with Wizard, Arthur and Sultan sown in mid March and compared to Fuego and Tattoo. Results were that yield can be up to 30% lower yielding on less productive sites but can also be comparable to Fuego on more productive land. Maturity is likely to be around 10-12days later than Fuego sown at the same time, straw may be slightly taller, standing ability should not be unduly affected.
Growers are advised to be sure that seed bed conditions are suitable for later sowings.
These results are from one year only and whilst a good indication should be considered carefully.
*Please note high cv for Cambs trial, this figure reduces the confidence in this particular trial. All trials sown mid March, 2010.