How to make the most of a September oilseed rape drilling window

Planting oilseed rape on into September is very much an option this season - providing conditions remain favourable. 

 In the south and south-west of England, OSR is successfully planted well into September as a matter of routine, says NIAB break crop specialist Colin Peters, who suggests September drilling could well be an option for growers up into the Midlands, as long as conditions are good.  

“It comes down to assessing the conditions and only drilling if conditions are right - the seedbed is good, there is moisture available and flea beetle levels are low,” says Mr Peters. 

 “If you’ve got warm, moist seedbed conditions your crop will be out of the ground like a bullet, but there is no point in drilling if it is hard and dry.” 

 Only time will tell if the low cabbage stem flea beetle numbers seen through to late August persist. Yellow water trap monitoring, which can now be done remotely with Bayer’s newly launched MagicTrap digital yellow water trap, will be useful to keep a check on flea beetle numbers. 

 All the usual good agronomic practices associated with August oilseed rape establishment still apply, although variety selection may need tweaking, says Mr Peters. 

 “There are some varieties that potentially show better bulking up in the cooler conditions and shorter days as we go into the autumn. 

“If I were drilling later, I would be investing a little bit more in genetics, so I would be looking for a hybrid, but I wouldn't necessarily be drilling it any thicker. I don't think that will give you any advantage - you're looking for size of plant, not more plants.” 

Later drilling can also open up a wider window to address any soil structural issues, incorporate organic manures and tackle problem grass-weeds with Roundup, all of which are important considerations after the wet weather-disrupted harvest 2024 season, suggests Bayer technical manager Ellie Borthwick-North.  

 “We really do need to get away from calendar date thinking where OSR drilling is concerned. It is drilling conditions that really count.  If soils have plenty of moisture and sufficient warmth for rapid germination and early crop development, with the much more open autumns and early winters we’re getting these days there is more than enough time to establish resilient and productive canopies ahead of winter,” she says.  

Key to success with September sowing is to get crops up and away quickly, says Ms Borthwick-North, who suggests there are eight ‘establishment essentials’ to put in place:  

• Eliminate compaction, which is particularly harmful to OSR rooting, through targeted subsoiling, preferably with minimal soil disturbance to preserve soil moisture 

• Use well-proven hybrids such as DK Excentric and DK Excited with their fast rates of autumn development and excellent establishment vigour 

• Whatever the establishment regime, aim to sow at a consistent depth into well-firmed soil for even and rapid crop emergence 

• Prioritise seedbed N and P, especially where minimal tillage and/or previous crop residues may temporarily restrict nutrient availability 

• Resist the temptation to increase seed rates more than marginally to avoid higher-than-ideal plant populations 

• Roll soon after drilling, wherever possible, to improve seed-to-soil contact, retain moisture and restrict slug activity 

• Apply carefully targeted ferric phosphate pellets within 24-48 hours of sowing to tackle slug problems 

• Register for the 2024 Dekalb Establishment Scheme  

With the prospect of oilseed rape drilling continuing into September, United Oilseeds’ seed manager Beckii Gibbs sees the Dekalb Establishment Scheme as insurance on an investment.   

“Having that little extra peace of mind can give growers the confidence to make the initial investment in the crop,” she says.  “If you are a first-time grower of OSR and perhaps haven’t had the opportunity to perfect your agronomic strategy, choosing a variety with an establishment scheme seems like a no-brainer.” 

Ms Gibbs advises growers to check dates and deadlines associated with any establishment scheme, as well as the varieties covered. 

 “The DK scheme is available across all DK varieties giving growers the freedom to choose a variety that is right for them,” she says.  

 “Choose a variety that has an establishment scheme. Don’t be afraid to re-consider drilling dates depending on weather and pest pressure and further spread the risk by contracting to one of the United Oilseeds marketing pools,” she concludes.