Planting the 2018 winter wheat crop

Much of wheat’s yield potential is determined at planting. Attain top yields by having a uniform stand that has time to achieve significant growth before winter dormancy.

Planting the 2018 winter wheat crop

Seeding date

Ideally, winter wheat is planted while the soil and air temperatures are still warm to insure the seedling can emerge quickly and uniformly in plenty of time to develop multiple tillers and a strong root system. In fact, beginning in mid- to late September, potential wheat yields tend to slip at least one bushel for every day planting is delayed. This relationship may not hold, however, once the calendar reaches late October as soil and weather conditions tend to play a more important role.

While the Hessian fly no longer poses a significant threat to wheat in Michigan, the fly-free-date is still a useful reference. The 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 seedings are made within two weeks following the posted fly-free-date. When wheat is planted within a few days of the fly-free-date, seeding rates and fall-applied nitrogen rates should be reduced.

Seeding depth

Attaining a consistent seed depth is important because it will increase the probability of even emergence. Usually, a planting depth of 1 to 1.5 inches is sufficient 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. Where planting depths of 2 inches or greater may be advantageous is when a coarse soil is very dry. In this case, seed should be planted as deep as possible in order to come in contact with moisture.

Seeding 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 week of the fly-free-date. Using high seeding rates are discouraged when seeding relatively early as it may lead to overly thick stands that tend to lodging as the plant approach maturity.

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 1.8 million seeds per acre. The seeding rates should also be adjusted upward when seed is of questionable quality.

Table 1 identifies the pounds of seed needed based on the number of seeds per pound and your population target. For example, if the seed bag specifies 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. 

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

Seed size (seeds/ lb.)

Target seeding rates (millions of seeds per acre)

1.6

1.7

1.8

1.9

2.0

2.1

Amount of seed required (lbs./acre)

10,000

160

170

180

190

200

210

11,000

145

155

164

173

182

191

12,000

133

142

150

158

167

175

13,000

123

131

138

146

154

162

14,000

114

121

129

136

143

150

15,000

107

113

120

127

133

140

16,000

100

106

113

119

125

131

17,000

94

100

106

111

118

124

18,000

89

94

100

106

111

117

* 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)

Target seeding rate (millions per acre)

Seeds per feet of row¹

Seedlings per feet of row²

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%)

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).

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

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