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On March 07, 2020

To Renovate Your Pastures With Frost Seeding

With the recent warmup and the lack of snow cover over Pennsylvania, things are starting to look green over the landscape.  As we begin to shift from winter and think of early springtime tasks, one of the first on your list should be evaluating the condition of your pastures.  If stands are thin, Extension Agronomists Dwane Miller and Justin Brackenrich recommend frost seeding as an option to thicken pastures.

Before talking about seeding, it is important to note that frost seeding (or overseeding of pastures in general) is not a substitute for addressing poor fertility of pastures.  Proper pH and fertility are essential for desirable production of pastures.  Soil tests should be taken regularly (at least every 3 years), and corrective measures taken.

Although using some type of tillage to renovate pasture has a higher rate of success, using frost seeding is a less expensive option that can be effective if done at the right time and managed properly.  One major factor in frost seeding success is achieving maximum seed-to-soil contact.  Often times, a pasture that has been very aggressively grazed into the fall will present a good opportunity for frost seeding.  Using a chain drag or running over the field lightly with a disk can open the stand as well. Another way to achieve good seed to soil contact is through the trampling effect of livestock.  

Frost seeding works as the ground ‘honey combs’ during this time of year.  As temperatures climb above freezing during the day, but drop below freezing at night, soils open and close, working seed downward and from the soil surface.  Seeding early in the morning before the soil surface begins to thaw is recommended.  If the soil surface is “slimy”, wait to seed until you get another morning when the soil has frozen again.

Most often, we recommend using frost seeding to introduce forage legumes into an established stand.  Legumes have a much better success rate than grasses.  Red clover is usually the species most recommended for frost seeding, due to its seedling vigor and wide tolerance to pH, fertility, drainage, and drought.  Obtaining a desirable stand of grass species from frost seeding is much more difficult.  Research at the University of Wisconsin (West and Undersander, 1997) showed that perennial ryegrass and orchardgrass exhibited the best establishment success.  If you plan to attempt frost seeding of a grass, be aware that you will need to make a separate pass with your seeder, as grasses will not spread as far as legumes.

Frost seeding can be done with any type of a broadcast seeder.  This can be done with a hand seeder, a tractor 3-point hitch mounted unit, or a broadcast seeder on an ATV.

For more information, including best species for frost seeding and seeding rates, see Frost Seeding Legumes and Grasses into Pastures  https://fyi.extension.wisc.edu/forage/frost-seeding-legumes-and-grasses-into-established-pastures/  by University of Wisconsin- Extension. 

To Control Weeds In Alfalfa

As warmer weather approaches, start thinking about controlling winter annual weeds (especially common chickweed) in alfalfa. Extension Weed Specialist Dwight Lingenfelter explains once the temperature rise and alfalfa starts breaking dormancy, it can quickly grow beyond the growth stage to safely spray some of these products. In most cases, 2-inches of alfalfa regrowth is the maximum height listed. Spraying beyond this stage may cause stand and/or yield reductions. Keep in mind all of these herbicides are labeled for use in pure-stand alfalfa. However, only metribuzin, Pursuit, Prowl H2O, and Aim can be applied to established alfalfa-grass mixes. Here are a few guidelines about available products:

Your best bet when controlling Chickweed is Gramoxone SL, Pursuit, Raptor, or Metribuzin (if chickweed is ALS-resistant, Pursuit and Raptor will not control it.). For Annual bluegrass use Gramoxone SL and for Henbit or deadnettle the best choices are Gramoxone SL or Metribuzin. If Yellow rocket is the problem use Pursuit, Raptor, or Metribuzin. For Palmer amaranth use Gramoxone SL+ Prowl H2O or Chateau after 1^st or 2^nd cutting (pure stand alfalfa only)

Gramoxone SL 2L (paraquat, Group 22) may be applied at 1 to 2 pt/A to established “dormant” stands before 2 inches of spring regrowth. (Keep in mind, there is a new higher load formulation, Gramoxone 3L, in which lower rates will be used.) The weeds must be actively growing at the time of application. Gramoxone is also labeled at 1 to 2 pt/A for dormant application on new fall seeded stands. 1 pt/A can be applied between cuttings but no more than 5 days after harvest and before 2” of regrowth. Gramoxone will desiccate any green tissue including actively growing alfalfa and possibly cause stand and/or yield reductions. However, if chickweed infestations are thick, this may be a necessary option to help suppress it. Be especially cautious with new fall seedings. Do not tank-mix with metribuzin on newly seeded (less than 1-year old) alfalfa. Gramoxone is effective on low to moderate infestations of winter annuals including chickweed, henbit, deadnettle, and mustard species. Do not use on mixed stands.

Pursuit 70DG (imazethapyr, Group 2) may be used for weed control in seedling (2 trifoliates or larger) or established alfalfa. Apply Pursuit at 1.08 to 2.16 oz/A plus adjuvants to actively growing weeds 1 to 3 inches in height. Pursuit performance improves with warmer temperatures. If spraying during extended cold periods, expect weeds to respond slower or the herbicide can have reduced activity. Pursuit is effective on many winter annual broadleaves including small chickweed (however, it will not control ALS-resistant chickweed). Pursuit may be used on established alfalfa-grass mixtures.

Raptor 1AS (imazamox, Group 2) may be used for weed control in seedling or established alfalfa. Apply Raptor at 4 to 6 fl oz/A plus adjuvants to small, actively growing weeds and to established alfalfa in the fall or in the spring. Any application should be made before significant alfalfa growth or regrowth (3 inches) to allow Raptor to reach the target weeds. Like Pursuit, Raptor performance is influenced by temperature. Therefore, try to apply the herbicide on warmer days and when weeds are actively growing. Raptor has a similar spectrum of winter annual weed control as Pursuit. Do not use on mixed stands.

For more information see the Agronomy Guide and always read and follow the label instructions.

Quote Of Week: “I’m a success today because I had a friend who believed in me and I didn’t have the heart to let him down.”  Abraham Lincoln