Have you ever seeded a pasture or hay field and still have seed in the back of your pickup truck or trailer that was meant to be in the soil upon completion of the seeding? How about getting 85 percent of the field sown and there was no seed left in the back of the pickup truck or in the trailer to complete the task? These problems can be avoided with proper calibration of the seeder.
Remember to calibrate your seeder! (Photo Credit: Keith Johnson)
Your seeder likely came with instructions on how to calibrate it. If the instructions cannot be found, or you would like to try an approach to calibration that works well, note the following steps.
Calibrating a Drill for Seeding Rate
- Determine from a reputable source the desired Pure Live Seed pounds delivered per acre.
- Determine the Pure Live Seed percentage of the desired seed from the seed tag. (% Purity x % Germination / 100 = % Pure Live Seed)
- Determine the bulk seed per acre seeding rate.
- Attach plastic bags to several detached seed tubes.
- Drive at seeding speed a determined marked distance (at least 100 feet.) and collect seed in the bags.
- Weigh the collected seed to the nearest gram. Inexpensive gram scales are available.
- Determine the seeding rate with algebraic equations.
- Adjust flow of seed to meet the desired target weight.
Example
- 15 pounds pure live seed alfalfa per acre
- 90 percent Pure Live Seed
- 15 pounds pure live seed per acre / .90 = 16.7 pounds bulk seed per acre is the target
- Collected seed from four tubes on a drill that has 7 inch row spacing.
- 4 rows x 7 inches per row = 28 inches / 12 inches per foot = 2.33 feet
- 33 feet x 100 feet driving distance = 233 square feet / 43560 square feet per acre = 0.00535 acre
- 00535 acre x 16.7 pounds per acre = 0.0893 pound seed target collected.
- 0893 pound seed x 454 grams / pound = Target of 41 grams target to be collected
Calibrating a Broadcaster or Cultipacker Seeders for Seeding Rate
- Determine from a reputable source the desired Pure Live Seed pounds delivered per acre.
- Determine the Pure Live Seed percentage of the desired seed from the seed tag. (% Purity x % Germination /100 = % Pure Live Seed)
- Determine the bulk seed per acre seeding rate.
- Multiply the bulk seed per acre seeding rate by the number of seed per pound (from 2017-Section-2.4-or-Table-2A.pdf (analyzeseeds.com) Or better, determine seed per pound by weighing a gram (suggested) and counting to get seed per acre.
- Divide number of seed per acre by 43560 square feet per acre to determine the number of seed per square foot.
- Drive the tractor at seeding speed with seeder attached on a surface of contrasting color for several yards so the number of seed per square foot can be counted. Take several readings and average the numbers to get a value.
- Adjust flow of seed to meet the desired number of seed per square foot.
Example
- 15 pounds of pure live seed alfalfa per acre
- 90 percent Pure Live Seed
- 15 pounds of Pure Live Seed per acre / .90 = 16.7 pounds bulk seed per acre is the target
- 227,000 seed per pound x 16.7 pounds bulk seed per acre = 3,790,900 seed per acre
- 3,790,900 seed per acre / 43,560 square feet per acre = Target of 87 seed per square foot
Avoid the frustration of seeding too little or too much seed. Take time to calibrate your seeder so the desired amount of seed is sown. It is a “best management practice” that needs to be done. It is worth the time!
