Oklahoma State University




Traditionally, switchgrass is planted into a clean-tilled seedbed; however, there has been an increased interest in no-till establishment. Regardless of the seeding method, a critical factor for success is planting the seed into a moist, firm (not wet or hard) seedbed. This will allow for greater seed-to-soil contact, which is extremely important so the seed can absorb the moisture necessary for germination. Soil texture and soil depth within a site will determine the moisture availability, and thus influence the choice of planting method.

A good switchgrass seedbed is firm and has no clods.
The shoe impression did not sink into the soil (firm),
yet it made a clear impression. For sandy soils, more
small clods would be desirable to inhibit wind erosion.

Seed depth
Seed should be placed at a depth of 1/4 to 1/2
inch and drill rows should not be so deep that
soil is washed in on top of the seeds.

No-till seedbed
A no-till seedbed for switchgrass establishment.


Seed Quality

Historically, the logical place to begin when planning a new forage seeding is to begin with the pure live seed (PLS) concept. The concept of using PLS is important because switchgrass seed often varies widely in quality and cost. Some seed lots can contain large amounts of inert material and undesirable seed. Because only live seeds are of value, the PLS method is the method used for buying, selling, and planting most forage seed.

It should be noted, the Oklahoma state seed law requires all seed sold must have a label including kind and variety, pure seed (percent), other crop seed (percent), inert matter (percent), and weed seed (percent). All noxious weeds must be listed in number per pound. Germination plus any dormant percentages and the date of test also are shown. The seed should be retested if the analysis is more than a year old. The labeler’s name and city/state are required as well. Be sure to read the label and understand the quality of the seed.

Seed quality is a primary consideration for switchgrass establishment. Thus, it is important that switchgrass seed be tested at a reputable seed testing laboratory, so the seed germination percentage, seed purity, and percentage of dormant seed is known. Seed dormancy may be the most critical factor determining successful switchgrass establishment. Dormant seed is classified as live seed. However, a dormant seed will not germinate until the dormancy is eliminated. This can occur either with time or wet-cold stratification.


Time of Seeding

A general rule of thumb is to plant switchgrass during the same establishment window as corn; however, seeding date for switchgrass is somewhat variable and depends on the method. Seed germination for switchgrass occurs around 60° F and higher. Based on this, a normal time of seeding for switchgrass in the southern Great Plains is between April 1 and May 1. Nevertheless, it is not uncommon for dormant season plantings to occur from January through March. Seeding at this time is not for earlier germination, but rather an attempt to overcome some of the challenges of seed dormancy.

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