MSU Extension

Much of wheat’s yield potential is determined at planting. To attain top yields, the goal of the planting operation needs to be an even and uniform stand of seedlings. This, along with timely planting, is critically important if improving wheat performance is the goal.

Field preparations

The chance of achieving a consistent stand is greatly improved by insuring that residue from the previous crop is spread uniformly. Particularly for no-till operations, bunched-up residue is the most common threat to evenness in wheat stands. In some cases, the coulters are unable to cut through the thick residue or the emerging wheat simply rots below the layers of plant material. Adding weight to the drill may help in penetrating crop residue, or hard soil. In some cases, the only alternative would be to use tillage to help disburse and bury the residue.

Planting date

While the Hessian fly no longer poses a significant threat to wheat in Michigan, the Hessian fly-free-date is still a useful reference relative to wheat projecting wheat performance and disease development (see table at the end of this article for county fly-free dates). Highest yields are often attained when planting 10 to 20 days following the fly-free-date. This timely planting helps ensure that seedlings have sufficient time to develop a strong root system and initiate multiple tillers before winter dormancy.

Where planting is delayed a few weeks beyond the fly-free- date, the crop’s yield potential tends to decline at least one bushel for each additional day of delay. When wheat is planted before or within a few days following of the fly-free date, growers should consider lowering their seeding rate; decreasing or eliminating nitrogen fertilizer at planting-time; and monitoring the seedlings for aphids.

Seeding depth

Attaining a consistent depth and thus even emergence is often more critical than fine-tuning actual seeding depth. Usually, a planting depth of approximately 1 inch will be deep enough to reach adequate soil moisture, provide for well-anchored plants, and offer some protection against winter injury. An exception, however, is where the soil is exceptionally dry. In this case, the seed should be placed as deep as necessary to find moisture.

Planting rate

Michigan State University Extension’s recommendation is to plant between 1.4 and 2.2 million seeds per acre. Seeding rates on the lower end of the range should be reserved for fields being planted within a couple weeks of the fly-free-date. Higher rates at this time are discouraged as overly thick stands may encourage lodging. As the planting season goes on, the seeding rates should become progressively higher. If planting continues into the second half of October, the seed rate should be increased to at least 2.0 million per acre. The seeding rates should also be adjusted upward when seed is of questionable quality.

Table 1 identifies the pounds of seed that a grower would need based on the seed count per pound and his target seeding rate. For example, if the seed bag specifies that there are 14,000 seeds per pound and the target seeding rate is 1.8 million seeds per acre, 129 pounds of seed would be needed per acre. Table 2 is useful for assessing the number of seeds being dropped by each row unit (7.5-inch row spacing) and for evaluating actual emergence.

Fall fertilization

Approximately 10 to 25 pounds of fertilizer nitrogen is recommended at the time of planting. All phosphorus and potash should be applied in the fall with rates determined by soil test levels. In general, soils having medium test levels of phosphorus (25 to 40 ppm) require approximately 50 pounds per acre of phosphate. For soils testing medium for potassium (75 to 100 ppm), approximately 100 pounds per acre of potash may be sufficient.

Table 1: Relating seed size and seeding rates to the amount of seed required per acre

* Seeds per acre / seeds per lb. = lbs. of seed per acre

Table 2. Relating target seeding rate per acre to seed and seedling numbers (for 7.5 inch-row spacing)

¹ Target seeding rate/ 43560 X 0 .625 = seeds per ft of row (7.5” spacing). Seeds per sq. ft. = target seeding rate/43,560.
² An estimated emergence rate is given in brackets as percent (the rate tends to decline as seed rates increase).