Planting the 2023 Wheat Crop

Dennis Pennington<pennin34@msu.edu>, Martin Nagelkirk and Maninder Singh<msingh@msu.edu>, Michigan State University Extension - September 06, 2022

Much of wheat’s yield potential is determined at planting. To attain top yields, timely planting coupled with appropriate seeding practices can be critical for ensuring an even and uniform stand.

Winter wheat growing in a field. — Photo by Dennis Pennington, MSU

Planting preparations

Achieving top yields requires a uniform stand of healthy seedlings. This is dependent on seeds being dropped as evenly as possible and at a uniform depth. Good seed placement, in turn, requires that fields are appropriately prepped, and planting equipment receive disciplined inspection, necessary adjustments and deliberate calibrations.

Tillage systems

Wheat establishment can be successful under conventional, minimum tillage and no-till systems. Generally speaking, no-till has won favor in recent years. It tends to result in more unevenness in the stand, but it can often provide improved moisture retention and less susceptibility to cold temperature damage. Tillage, even at a minimal level, can be helpful in distributing and incorporating residue, fertilizer and lime; and create a more uniform seedbed. Tillage can also be useful when attempting to reduce disease inoculum borne in crop residue (e.g. corn stubble or stalks infected with Fusarium).

Seeding date

Ideally, winter wheat is planted while the soil and air temperatures are still warm to ensure that seedlings can emerge quickly and in plenty of time to develop a couple of tillers and a strong root system. In a recent study conducted by MSU extension, yield loss of about 0.6 bushels per day occurs when planting after October 1.

While the Hessian fly no longer poses a significant threat to wheat in Michigan, the fly-free-date is still a useful reference (Table 1). The standard fly-free-date is during the first week of September in the northern Lower peninsula, around mid- September in mid-state areas and approximately the third or fourth week of September for southern Michigan. Highest yields are often attained when seedlings emerge within two weeks following the posted fly-free-date, assuming heat unit accumulation is near normal in October and November. When wheat is planted within a few days of the fly-free-date, seeding rates and fall-applied nitrogen rates should be significantly reduced to avoid excessive growth. The goal is to plant early enough to achieve 2-3 tillers produced prior to the winter vernalization period.

Table 1. Hessian fly-free-dates for Michigan
County	Sept.	County	Sept.	County	Sept.	County	Sept.
Alcona	6	Eaton	16	Lapeer	15	Ogemaw	10
Allegan	20	Emmett	4	Leelanau	8	Osceola	10
Alpena	9	Genesee	17	Lenawee	25	Oscoda	7
Antrim	4	Gladwin	12	Livingston	16	Otsego	6
Arenac	13	Grand Traverse	8	Macomb	18	Ottawa	19
Barry	18	Gratiot	15	Manistee	13	Presque Isle	8
Bay	14	Hillsdale	19	Mason	13	Roscommon	7
Benzie	16	Huron	13	Mecosta	12	Saginaw	16
Berrien	23	Ingham	17	Midland	15	Sanilac	15
Branch	19	Ionia	16	Missaukee	9	St. Clair	16
Calhoun	19	Iosco	7	Monroe	21	St. Joseph	23
Cass	22	Isabella	11	Montcalm	15	Shiawassee	16
Charlevoix	3	Jackson	16	Montmorency	7	Tuscola	15
Cheboygan	4	Kalamazoo	20	Muskegon	18	Van Buren	22
Clare	12	Kalkaska	5	Newaygo	15	Washtenaw	18
Clinton	17	Kent	18	Oakland	16	Wayne	18
Crawford	6	Lake	13	Oceana	16	Wexford	9

Oftentimes, weather conditions make it difficult to plant wheat on time. How late a wheat crop can be planted is really a question of how much risk a grower is willing to take. If a grower expects to have the crop insured, then the answer is straightforward because Oct. 25 is the last planting date for crop insurance eligibility. For those trying to estimate the odds of achieving a reasonable yield, it is important to recognize that the challenge to late wheat is not only the inherent constraints on grain yield, but also its greater susceptibility to winter injury.

Planting wheat on time starts with the previous crop. Soybean fields that are to be planted to wheat in the fall can benefit from management considerations such as optimum planting time and maturity group (MG) selection (Figure 1). Selection of late-maturity soybean varieties (e.g. 3.0 compared to 2.0 MG around Lansing) before May 15 planting can lead to 5-8 bu/ac increase in soybean yield, while still reaching maturity by late-September. This system would provide greater soybean yields while allowing adequate time for an optimum wheat planting date after soybean harvest. However, for later soybean plantings (after mid-May), early-maturity varieties can be used without a soybean yield penalty while allowing adequate time for wheat planting.

Figure 1. Impact of planting date and maturity group selection on soybean seed yield (bu/acre, left panel) and date to reach R7 stage (one mature pod on the main stem, right panel). Add 15-20 days to R7 to estimate harvest date. Data is average of four Michigan site-years.

Seeding depth

Attaining a consistent seed depth is important in order to increase the probability of even emergence. Usually, a planting depth of 1 to 1.5 inches is enough in heavy soil. Deeper seed placement may have an advantage when some types of winter stresses occur, but usually this is outweighed by the advantage in more rapid emergence posed by more shallowly placed seed. The exception may be where a coarse soil is very dry. In this case, seed should be planted as deep as possible to reach moist soil.

Seeding rate

The recommendation is to plant between 1.2 and 2.0 million seeds per acre. Seeding rates on the lower end of the range should be used when planting within a week of the fly-free-date to avoid overly thick stands that can promote disease development and increase the likelihood of lodging the following season. As the calendar advances, seeding rates should become progressively higher. If planting continues into the second half of October, the seeding rate should be increased to at least 1.6 million seeds per acre.             

Table 2 identifies the pounds of seed needed based on the number of seeds per pound and your population target. For example, if seed size is 12,000 seeds per pound and the target seeding rate is 1.4 million seeds per acre, then 117 pounds of seed would be needed per acre. Table 3 is useful for assessing the number of seeds being dropped by each row unit (7.5-inch row spacing) and for evaluating actual seedling density. So, with the 1.4 million target, a 7.5-inch drill would drop approximately 20 seeds per foot and, assuming a 92% emergence rate, lead to an estimated 18.5 wheat seedlings.

Table 2. Relating seed size and target seeding rates to the number of pounds required per acre
Seed size (seeds per pound)	Target seeding rates (millions of seeds per acre)
	1.2	1.4	1.6	1.8	2.0	2.2
	Actual pounds of seed required per acre *
9,000	133	156	178	200	222	244
10,000	120	140	160	180	200	220
11,000	109	127	145	164	182	200
12000	100	117	133	150	167	183
13,000	92	108	123	138	154	169
14,000	86	100	114	129	143	157
15,000	80	93	107	120	133	147
16,000	75	88	100	113	125	138
*Target seeding rate divided by seeds per pound = required pounds of seed per acre.

Table 3. Relating target seeding rate per acre to seed and seedling numbers (for 7.5-inch row spacing)
Seeding rate (millions/ac)	Seeds per foot of row	Seedlings* per foot of row
1.2	17.2	16.2 (94%)
1.4	20.1	18.5 (92%)
1.6	23.0	20.7 (90%)
1.8	25.8	22.7 (88%)
2.0	28.7	24.7 (86%)
2.2	31.6	26.5 (84%)
*Projected number of seedlings based on an estimated declining emergence rate as percent.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).

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