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University of Minnesota Extension

Seeding depth

How deep do I drill wheat, barley and oats down to find moisture?

Under most conditions, the optimum seeding depth for small grains is 1.5 to 2 inches.

Aim to place the seed in a zone with ample moisture, but shallow enough so the crop can quickly emerge. Adjusting and monitoring your seeding depth is critical.

Deep seeding

Cooler soil temperature at the depth of the seed increases emergence time.

Deep seeding requires greater seedling vigor, reduces the number of seeds that emerge and may eliminate the emergence of the coleoptile tiller. This reduces the stand’s vigor, increasing the risk of seedling diseases and developing root rot.

Soil crusting, cold weather or other adverse conditions make deeper seeding risky. Unless conditions are favorable, yield losses occur due to deep seeding.

How variety affects planting depth

The introduction of semi-dwarf varieties in wheat has made depth control more important because semi-dwarf wheat tends to have shorter coleoptiles. The coleoptile is a leaf sheath that surrounds and protects the first true leaf as it grows from the seed toward the surface.

If the coleoptile is shorter than the depth of planting, emergence becomes difficult and the first leaf may not reach the surface, ultimately dying and resulting in stand loss.

Correlation between plant height and coleoptile length

Overall plant height and coleoptile length are correlated. Taller varieties tend to produce longer coleoptiles.

If you’re planting a taller wheat variety, you generally have more latitude with planting depth. When planting shorter semi-dwarfs, maintaining a shallower planting depth becomes crucial.

Barley varieties tend to have shorter coleoptiles than wheat, also demonstrating the need to carefully calibrate and monitor planting depth.

Jochum Wiersma, Extension agronomist; Joel Ransom, Extension agronomist and Vern Hofman, emeritus agricultural engineer, North Dakota State University

Reviewed in 2018

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