Lift seed rates for winter beans drilled very late

Bean growers can still achieve reasonable crop yields when drilling winter varieties in the spring, providing they lift the seed rates.

One of the wettest autumns for many years has resulted in delayed drilling on many farms and one key question being asked by growers is: how late can winter beans can be grown?

In fact for some growers, it’s so wet that drilling may have to be abandoned until next spring, leaving unused winter seed, especially as winter beans will rot in waterlogged soils.

See also: How to sample your grain on farm to get the top price

But trials carried out by the Processors and Growers Research Organisation in autumn 2012 – the last time conditions were very wet – offer some reassurance that not all is lost. 

It concluded that winter beans sown in the spring are not a disaster, even at 18 plants/sq m. However, maturity is later – by the order of 7-12 days for Wizard.   

Results also show that growers should treat them as spring beans, by increasing the plant population to levels more like that of spring varieties (typically 40 plants/sq m).

In the 2012 trial, winter bean varieties Wizard and Clipper were sown at three sites, at four populations and and at three sowing dates.

The results from the sites at Dowsby, Lincoln and Thorney were:

  • On average, winter beans Wizard and Clipper sown in the spring at 18 plants/sq m gave a 34% yield reduction compared with autumn sowings at the same population.
  • This yield gap was lowered to 18% on average by planting at 36 plants/sq m in the spring compared with 18 plants/sq m in the autumn.
  • Spring sown winter beans at 36 plants/sq m did not match the yield of spring sown Fuego, with Wizard and Clipper yielding 83% and 90% of Fuego, respectively.
  • Autumn-sown Wizard and Clipper at 18 plants/sq m yielded as well as, or a little better than, spring-sown Fuego.
  • End-February sown Wizard matured 12 days later than mid-October drilled Wizard and seven days later than late-October drilled Wizard.
  • End-February sown Wizard matured eight days later than early-March sown Fuego.