Wallaces Farmer

Frost seeding, interseeding for pastures

Here are guidelines and considerations for improving pastures in late winter and spring.

Rod Swoboda

March 3, 2020

3 Min Read
tractor in field
INTERSEEDING: Production of low-yielding pastures can be doubled or tripled with the introduction of more productive grass or legume species.Wallaces Farmer

Now is time to be thinking about improving pasture stands by frost seeding in late winter, February and early March, by broadcasting the seed. Or, by using an interseeding method such as no-till drilling the seed later in the spring months. Iowa State University Extension field agronomists Rebecca Vittetoe and Meaghan Anderson provide the following considerations and guidelines. A retired ISU Extension forage agronomist also contributed to this article. 

Frost-seeding steps to success

Frost seeding involves spreading forage seed on existing pastures during late winter or very early spring, while the ground is still frozen. Freeze-thaw cycles then provide shallow coverage of the seed, which helps shield the seeds from early spring rains. Frost seeding is the easiest method to add new forage legumes to pastures, and is likely the least expensive method as well. To increase this method’s success, spread seed on the thinnest pasture sod areas first, and on areas where bare soil has been exposed due to heavy grazing or disturbance.

When it comes to frost seeding, don’t frost-seed on top of a snow cover. The goal of frost seeding is to get seed on bare soil. If snow accumulates after you’ve frost-seeded on bare ground, that is perfectly fine.

Red clover has been the Iowa forage species of choice for frost seeding. Other legumes, such as white clover and birdsfoot trefoil, also can be frost-seeded, but with less success than red clover. In general, frost seeding doesn’t work as well with grasses.

A few well-researched steps will improve the success of frost seeding. Those steps, seeding rates and guidelines are available in the ISU Extension publication ”Improving Pasture by Frost Seeding.

Interseeding is another option

Interseeding offers an opportunity for improving pasture productivity, too. This involves using a no-till drill to add additional forage species into an existing pasture stand. Interseeding is normally done from mid-March through early May, when soil moisture and temperature are more suitable for rapid seedling establishment.

Interseeding can be accomplished with relatively few field operations. Opening of the grass sod, shallow seed placement and seed coverage are required. While a number of drills are available for use in sod-seeding efforts, drills vary in their effectiveness based on ability to penetrate sod, provide uniform seed depth and metering, and ability to cover the furrow. Equipment limitations for sod-seeding implements sometimes are overcome by operator experience and home shop modifications.

Clovers, alfalfa and birdsfoot trefoil are legumes that have been successfully interseeded. Legumes interseeded into grass sod will help increase pasture yield, improve forage quality, and eliminate or minimize the need for nitrogen fertilizer. Perennial forage grasses can also be successfully established by interseeding. Thin, low-producing grass sod might best be improved by interseeding a grass and legume mixture.

Control existing competition

Delaying seeding into late spring to improve growing conditions often also leads to greater competition from the existing grass sod. Close grazing in the fall or spring, ahead of interseeding, will help to reduce sod competition. Contact herbicides are sometimes also used to further reduce competition temporarily from plants present in the stand. Use only labeled herbicides for sod suppression, and follow label instructions.

Interseeding success depends a lot on paying attention to details, timeliness, careful management of sod competition, controlling seeding depth to no deeper than a quarter-inch to a half-inch — and a little bit of luck with weather.

Interseeding research has been conducted in many parts of the U.S. and around the world. It shouldn’t come as a surprise that the conclusions from these efforts all point to several very important conditions that must be met for successful interseeding. See ISU Extension publication “Interseeding and No-Till Pasture Renovation” for suggested seeding rates and guidelines. For more information and answers to specific questions, contact your local Iowa State University Extension and Outreach field agronomoist. 

Source: ISU, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all of its subsidiaries are not responsible for any of the content contained in this information asset.

 

 

 

About the Author

Rod Swoboda

Rod Swoboda is a former editor of Wallaces Farmer and is now retired.

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