Spring 1995
Tips for Planting and Replanting
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Prairie Grains is the
official publication of
the Minnesota
Association of
Wheat Growers,
North Dakota Grain
Growers Association,
South Dakota Wheat,
Inc., and the
Minnesota Barley
Growers Association.
Probably the best planting depth for small grains is between 1 and 1 1/2 inches. Planting closer to the soil surface is desirable for quick emergence and helps establish a quick stand to compete against weeds. However, during a dry spell the seed could germinate, and a new seedling may be killed in dried out soil.
Planting deeper than 2 inches places seed in cooler soil and increases the time for plants to emerge. If seed is planted deeper than 3 to 4 inches, some seedlings may never emerge.
Uniform seeding depth has been difficult to maintain with older seeding equipment, says Vern Hofman, NDSU extension ag engineer. Newer equipment has solved many of these problems, however, as depth control has been incorporated into machine designs.
Plant as early as possible, as soon as a satisfactory seedbed can be prepared. In general, expect a one percent per day reduction in yield for each day that seeding is delayed after the optimum planting date, according to the University of Minnesota Extension Service.
In northern Minnesota, this decline in yield usually occurs after the first week in May and in the southern part after mid April.
At a 50 bushel/acre yield goal, this is one-half bushel per day.
The main factor contributing to yield reduction due to delayed seeding is the probability of higher temperatures during the 4.0 to 5.5 leaf stage or close to spikelet formation, when the number of spikelets on the head is determined.
Whenever maximum day temperatures reach above 63 degrees during this specific growth stage, the number of spikelets per spike decreases. Further, high temperatures (above 90 degrees) during grain fill will reduce kernel fill, thus also yield.
Stand establishment is the most critical factor in wheat production, according to Jim Helm, NDSU extension agronomist.
The ideal stand will consist of 25 to 35 plants per square foot (30 plants per square foot would be about 1.3 million plants per acre).
Some fields will have areas with less than 25 plants per square foot. If that is the case, sections may be replanted instead of replanting an entire field.
Leaving an undesirable stand risks less production and other problems such as weed competition. But on the other hand, replanting costs must be recovered from a later maturing crop that has a lower yield potential than the original crop. Plus, more moisture is used as a function of soil disturbance.
If reduced stands are uniform with no big skips or holes, consider keeping stands of 15 plants per square foot. If skips are large (three to six feet) or holes are four to six feet in diameter and stand is 18 plants per square foot or less, then consider replanting if moisture is adequate.
After June 1 in northern Minnesota and May 15 in southern Minnesota, a replant decision should be to a crop other than wheat or barley since yields are reduced by about 50 percent when planting after these dates compared to normal planting dates.