Late winter wheat sowing: seed rate may rise to 250 kg per hectare
Polish agricultural portal Farmer.pl explains that winter wheat sown in the second half of November should have its seed rate raised by at least 15%, and in some cases by up to 30%. The key figure is plant density per square metre, which should not exceed 500.
Polish farmers who are still considering sowing winter wheat in the second half of November need to adjust the seed rate per hectare. According to the agricultural portal Farmer.pl, increasing the rate for very late sowing is not only justified but necessary. Even 250 kg of seed per hectare is not necessarily too much, because plant density, rather than seed weight itself, is what matters most.
Why sow more densely
With late sowing, plants tillering in autumn for a shorter time or not at all. A higher plant count partly makes up for this loss. The portal notes that in this situation plant density is practically equal to the number of ear-bearing shoots.
Worked examples
In the first example, the optimal-date rate is 300 plants per square metre, while in mid-November it is 400. With a thousand-grain weight of 45 g and 95% germination, the difference is 47 kg: 142 kg/ha at the optimal date versus 189 kg/ha later.
In the second example, the seed has a thousand-grain weight of 50 g and 90% germination. Early sowing needs 240 plants per square metre, or 133 kg/ha, while at the end of November a density of 450 plants per square metre requires as much as 250 kg/ha. That is nearly twice the seed cost of the early date, but according to the portal it will most often still be a better decision than sowing a spring variety.
Recommendations
More cautious guidance suggests raising the rate by about 15–20%. This year, given last season's experience, denser sowing is more common, at 25–30% above the optimal-date rate. The maximum recommended density is 500 plants per square metre. The size of the increase depends on sowing date, the variety's capacity for spring tillering and soil conditions.
Late sowing also changes spring management: stimulating tillering in spring will likely be needed, and herbicide protection often shifts to spring as well. In three-spray programmes, fungicide treatments can sometimes be reduced by one, as growth stages are reached later.
