Source: Michigan State University Extension

By James DeDecker

Oct. 25, 2013 — Harvest operations are well underway on most Michigan grain farms, but the significant likelihood of above normal precipitation totals over the next couple of weeks could quickly return combines to the shed. Harvest delays mean that some of the state’s 2014 winter wheat crop will not be planted until well after the recommended seeding window of Sept. 18 to Oct. 8. Delayed planting increases the risk of poor stand establishment, limited fall tillering and cold injury. As of Oct. 18, 2013, the crop’s yield potential is already declining by at least one bushel each additional day that planting is delayed. That said, there are a number of adjustments that growers can make to maximize the yield potential of a late planted wheat crop.

Seed Treatment

Planting certified seed treated with a fungicide can help protect the crop from a number of seed and soil borne fungal pathogens. While the added cost of seed treatment is almost always recovered through increased yields, keeping plants free of disease is particularly important when yield potential is already compromised by delayed planting. Saved seed should be cleaned prior to treatment using a commercial seed conditioner to ensure thorough coverage.

Seeding Rate

Late seeding reduces the amount of time available for plants to develop roots and tillers prior to winter dormancy. Increasing seeding rates can compensate, to an extent, for this lack of fall growth and increase the crop’s yield potential. Michigan State University Extension recommends increasing seeding rates by 200,000 seeds per acre for each week that planting is delayed beyond the optimum seeding date for your area. If seeding is delayed four weeks or more, the maximum recommended seeding rate of 2.2 million seeds per acre should be used. Table 1 shows the pounds of seed needed to achieve a desired per acre seeding rate based on seed count per pound.

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)
10,000 610 170 180 190 200 210
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

Seeding Depth

Traditional guidelines suggest seeding wheat at a depth of 1-1.5 inches. In the case of delayed planting, seeding shallowly may encourage quicker and more consistent fall emergence. However, the potential advantage of putting on more above ground growth before dormancy must be weighed against an increased risk of winter injury due to shallow planting. Seeding late winter wheat as close as possible to 1 inch deep will help growers strike a balance between these concerns.

Nitrogen Fertilization

Many producers apply 10 to 25 pounds of fertilizer nitrogen to wheat in the fall. If planting is delayed more than a couple of weeks beyond the optimum seeding date, MSU Extension wheat educator Martin Nagelkirk recommends increasing nitrogen rates to 20-40 pounds per acre at planting. This additional shot of nitrogen will support vigorous seedling growth and encourage quick stand establishment, even as soils cool and mineralization of organic nitrogen slows.

Even if wheat planting is delayed significantly, until mid-November for example, acceptable yields can be achieved. Weather conditions after planting are, of course, the most important factor in achieving this goal. However, following the recommendations above will increase your chance of success.

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