Proper calibration of seeding equipment requires that the operator be able to calculate the number of seeds that will be planted per foot of row using the desired plants per acre. It is often beneficial to calculate seeds per acre from seeds per foot of row as well.
Seeds per foot of row = [seeds/acre]/43,560] x [row spacing/12]
where 43,560 is the square feet in an acre, row spacing is the distance between two adjacent rows in inches; and 12 is the inches in one foot.
The equation above can be manipulated to calculate seeds per acre from seeds per foot of row as well.
Seeds per acre = [43,560 x 12]/row spacing x seeds per foot of row
where 43,560 is the square feet in an acre, row spacing is the distance between two adjacent rows in inches; and 12 is the inches in one foot.
You are planting soybean in 15 inch rows and intend to plant at 200,000 seeds per acre. How many seeds per foot of row will be planted?
Seeds per foot of row = [200,000 seeds per acre]/43,560] x [15 inches/12]
= 5.74 seeds per foot of row
You calibrate your planter to drop 6 seeds per foot of row. During a test run you find that it is actually dropping 5 seeds per foot of row. If you do not change the settings on the planter, what will be your seeding rate in plants per acre?
Seeds per acre = [43,560 x 12]/15 x 5
= 174,240 seeds per acre