Seeding rate is among the many factors that affect grain yield that can be controlled. The ability to control seeding rate allows farmers flexibility in their management practices. For example, when fall seeding is delayed the tillering period is shortened. To compensate for this reduction in fall tillers, farmers can increase seeding rates.
To some extent, wheat is inherently capable of compensating for factors that influence yield. However, optimum seeding rate are required to optimize the plant population, which in turn is important for maximizing grain yield and quality and controlling weeds.
Seeding rates are typically expressed as seeds per acre or pounds per acre. Determining seeding rates using pounds per acre is problematic because seed size and weight can differ considerably among plant varieties. Seeding different varieties at the same pounds per acre can result in significantly different plant populations. Therefore, to maximize yield seeding rate recommendations in pounds per acre should be converted to seeds per acre.
Sometimes recommendations for good wheat stands are based on seedlings per foot of row. To use this recommendation, a farmer must decide the optimal number of seeds per foot of row at time of planting. This number can be estimated by identifying the target seedling number per foot of row and adjusting that number for seed germination and mortality rates. This adjusted target number of seedlings equals the number of seeds that should be planted per foot of row. The final seeding rate can then be calculated as pounds per acre.
Calculating seeding rates and converting among the different units of measure—seeds per acre, pounds per acre, or seedlings per foot of row—can be tedious and time-consuming. Washington State University has developed a user-friendly, online seeding rate converter that is now available for your convenience.