Jarrod O. Miller, Extension Agronomist, jarrod@udel.edu
Six different seeding rates for winter wheat were tested at the Carvel Research Center (Georgetown) over the past two seasons (2017-18 and 2018-19). Seeds were drilled at 0.9, 1.2, 1.5, 1.8, 2.0, and 2.4 million seeds per acre each fall and harvested the following summer. Averaged over the two seasons, yields ranged from 77-89 bu/acre, with some differences between seeding rates (Table 1).
Compared with the lowest seeding rates, yield increases were observed at 1.5 to 2.0 million seeds per acre. Within that range though (1.5 -2.0), yields were not found to be statistically different. This means you could expect similar yields if planting wheat between 1.5 to 2 million seeds per acre. Planting at 2.2 million seeds reduced yield back to 83 bu/acre, which was not found to be different from planting at 1.2 million seeds per acre.
These results support the general recommendation of planting winter wheat at a range of 1.5 to 2 million seeds per acre. Anywhere above or below this range may cause yield losses. Management, soil type, and weather could certainly shift these results, and may not be the same across the state. Soils in Georgetown are sandy with low moisture and nutrient holding capacity, and these results may fit those soil types the best.
Table 1: Yields from the different seeding rates
| Seeding Rate | Yield |
| 900,000 | 78 b |
| 1,200,000 | 77 b |
| 1,500,000 | 83 ab |
| 1,800,000 | 86 a |
| 2,000,000 | 89 a |
| 2,200,000 | 83 ab |
*Yields followed by the same letter are not different from each other (a=0.1)
Figure 1. Yields from the different seeding rates as a graph example.