Why September Drilling Can Still Work
Across the UK, more growers are proving that oilseed rape sown in early–mid September can establish well and deliver competitive yields—provided you manage seedbed conditions, variety choice and pest risk with intent. Several trial programmes and farm case studies point the same way: later drilling is no longer a last-ditch option; in many seasons it’s the right option.
Cabbage stem flea beetle (CSFB) pressure is closely linked to drill date. AHDB notes that crops drilled from late August into early September often coincide with peak adult migration—when seedlings are most vulnerable. Shifting drilling later so emergence falls after that peak can materially reduce damage.
On farm, this plays out. There are many reported successes from drilling in the first half of September including the recent world record set in the Lincolnshire Wolds, with emergence in mid–late September “missing” the key flea beetle migration and producing gross margins which would be on par with the highest performing crops on farm.
Breeders and trial managers back the window too. NPZ UK (previously known as LSPB) have repeatedly highlighted that many breeder and official trials are sown into September and still perform strongly, arguing that September remains a valid drilling slot for vigorous hybrids. Temperature analysis from Cambridgeshire & Lincolnshire suggest conditions are typically warm enough for establishment through much of September, and the data can be analysed for individual farm locations based on historical patterns.
What, then, are the keys to making late OSR work?
1) Choose the right genetics. Hybrid varieties with strong early vigour and fast autumn development help plants growth through vulnerable stages and compete with volunteers and companions. Guidance for later drilling has long favoured hybrids for this reason, and there are a number of suitable varieties within the ADM portfolio.
2) Drill for moisture, not the calendar. In dry Augusts particularly as we have seen over the past two weeks, waiting for a forecast that delivers seed-soil contact and uniform emergence is often more valuable than chasing an early date. Later drilling into moisture beats earlier into dust.
3) Stack establishment aids. Drilling methods which conserve moisture; consider increasing seed rates as we move into September, apply modest starter nutrition in the seedbed; and use rolling to seal in moisture. (Multiple establishment schemes now underwrite OSR to share risk, reflecting industry confidence in well-managed approaches.)
4) Use companion crops and cultural CSFB tactics. Companion species like buckwheat and berseem clover can confuse or cushion CSFB pressure, and also help offset some of the OSR establishment risk whereby growers are already signed into a companion cropping option within the Sustainable Farming Incentive (SFI).
5) Watch agronomy after emergence. September-drilled crops still need tight disease and weed monitoring. As an example, Phoma thresholds can be reached earlier on smaller, later-drilled plants – therefore it is important to treat at threshold however selecting varieties with strong Phoma resistance should counter this issue. Varieties such as Karat from NPZ UK with RlmS and Rlm12 phoma resistances give robust plant health.
Cut-off? There isn’t a single UK-wide “stop” date: location, latitude, altitude, soil, moisture and forecast matter more than the calendar, and it is important to remember the thermal time calculation for a crop to reach a sufficient size prior to winter dormancy (800-1000 day degrees). Recent on-farm results and trial networks show viable performance into mid-September where conditions allow. Use local data and be pragmatic about seedbed and weather.
In conclusion – with August having been dry in many areas, a planned early-September drilling – into moisture, with vigorous genetics and cultural support—can set OSR up for a strong, resilient start – please contact your ADM Farm Trader to discuss your requirements.
