Wheat Drill Calibration Tables

Chad Lee, Extension Agronomist, University of Kentucky

As producers gear up for wheat planting, calibration of the seeder is extremely important. Below are two tables to use as quick references in the calibration process. Most producers are using drills with 7.5-inch row spacing. The first table calculates how much seed to collect in 50 linear feet from one row of the drill. Target populations of 30 and 35 seeds per square foot are used for the calculations. The needed seed weights are listed as ounces (oz.) and as grams.

Wheat planting when futures are high and seed might be short

Chad Lee and Jim Herbek, University of Kentucky

Many producers locked in wheat contracts for 2011 at or over $7 per bushel and some are growing wheat for the first time in five years. There are rumors that seed supply is tight. If these rumors are accurate, there may be some temptation to skimp on seeding rates in order to cover more acres.  If you are one of those producers, just know what your risks are by cutting back and proceed with caution.

Maximum wheat yields normally require a final stand of 30 to 35 plants per square feet, but under the right conditions, stands as low as 20 plants per square foot will yield well. Getting a successful stand requires several things, including timely seeding, an accurate seeding rate, correct seed depth (1.0 to 1.5 inches), adequate soil moisture, and no seedling diseases.

Wheat should be planted from about October 10 to October 30 for most of Kentucky. This window is normally provides the best opportunity for getting a good stand and good growth before the cold winter months. Seed rates can be 30 to 35 seeds per square feet, but if you are considering dropping back a little, this is the time to try it. If planting occurs after October 30, then the seed rate should be 35 to 40 seeds per square foot. These seed rates assume a standard germination of 90%. For seed lots with lower standard germinations, a higher seeding rate is needed.

Drill calibration is absolutely necessary to dropping the correct amount of seeds. This process takes time and should be conducted with each seed lot you receive. If you do not have the time and/or patience for this procedure, then hire someone to calibrate your drill. This procedure will benefit your wheat production system.  Guidelines on calibrating wheat drills is available in the ID:125 Comprehensive Guide to Wheat Management, Chapter 4 “Planting and Drill Calibration” http://www.uky.edu/Ag/GrainCrops/ID125Section4.html.

Adjusting the drill for planting depth also takes time but will result in better stands. These adjustments need to be made in the field on the day of planting. Field conditions change from day to day and the pressure needed to get the desired depth may change day to day as well.

So, if you decide you are short on wheat and you want to skimp on seed, be sure you know the conditions in which you are planting. If possible, try to skimp in situations that will still provide a chance for good stand establishment. In a year when a large part of the 2011 crop may already be sold, skimping on seeding rates should only be used as a last resort.