One of the best ways to accomplish pasture renovation is by frost seeding, sometimes referred to as overseeding, and is an easy and relatively inexpensive way to establish legumes. Frost seeding is simply broadcasting legume or grass seed on existing grass pastures in late winter or very early spring when the ground is still frozen. Freezing and thawing, plus early spring rains, provide the only seed coverage.
Successful Frost Seeding Steps
1. Site Selection – Thinning grass stands have been a preferred site to use frost seeding. The pasture or hay field should be closely grazed or clipped in the fall or winter to open the stand and expose soil.
2. Soil Fertility – Proper soil pH and fertility are essential for efficient forage production. Soil tests should be taken.
3. Species Selection – Most frost seedings have been made to introduce or increase a forage legume species into an established grass stand. Forage quality is improved when legumes are added to grass stands. Research has proven that legumes will improve animal growth rates, milk production, and reproductive efficiency.
- Red clover has widely been accepted as the legume of choice for frost seeding. Red clover has high seedling vigor and is somewhat tolerant of a wide range of conditions relating to pH and fertility, drainage, and drought. Red clover stands last generally two years. Improved red clover varieties are FSG 402 and Bear Cat.
- Birdsfoot trefoil is slow to establish but is bloat-free and when established, does well in a wide range of conditions. A mixture of trefoil with red clover may be desirable. Red clover establishes quickly and produces well for one or two years, while trefoil stands improve with time and become the dominant legume as red clover dies out. Improved varieties are Pardee, Leo, and Norcen.
- White Clover and Ladino Clover will last somewhat longer than red clover, but is less tolerant of low fertility, drought, and overgrazing. Ladino and white clover stands may last three years or more. Improved varieties are Stamina and Crusade White Clover and Pinnacle Ladino Clover.
Regardless of the species, all seedings should be made with high quality, improved variety seed. While frost seeding is an economical practice, there is no justification to use low quality seed. The economics will be in favor of high quality, improved variety seed when you consider the entire lifetime of a stand. Grasses do not establish with the same level of success as do legumes.
4. General Seeding Rates for Frost Seeding
Forage Species // Seeding Rate (lb/A)
- Red Clover // 6-10
- Birdsfoot Trefoil // 5-8
- Ladino & White Clover // 2-5
5. Seeding Time and Method – The basic principal behind frost seeding is the “honey-combing” action that is created by alternating freezing and thawing cycles in late winter. To take advantage of these environmental changes, frost seeding should occur in late February or March. Seeding should be done when the ground is still frozen. Avoid seeding on heavy snow since a fast melt may wash off seeds. Frost seeding on top of snow, especially with fertilizer, is not recommended because rapid snow melting may cause the seed to be washed off the pasture.
6. Post-Seeding Management – Control of grass and weed competition during the first two or three months of the growing season is critical for the establishment of adequate legume stands. Use moderate periodic grazing after the grass starts growing but avoid close grazing. Some mowing may be necessary to help control grass and weeds.
Frost seeding can be an effective, economical means of introducing a new forage species or to maintain the current composition of a stand to an existing pasture and hay field. Frost seeding is frequently implemented where tillage is not a viable option because of erosion concerns. Desired results can be obtained when attention is paid to site selection, fertility, species selection, seeding rates, seeding times and method, and post-seeding management.
~ Written by : Scott Rushe – SEEDWAY , LLC Forage Market Development Manager