If you live in an area where the surface layer of soil freezes during winter, you can save fuel and equipment costs by frost-seeding a portion of your plots. Frost seeding involves spreading seed on frozen ground and allowing the freeze-thaw-freeze-thaw cycle that occurs as spring approaches to provide good seed-to-soil contact. When moisture in the top layer of soil freezes, ice expands upward, carrying soil with it. This process, called “heaving,” helps work small seeds like clover and alfalfa into the soil, the same way light disking or cultipacking creates good seed-to-soil contact. When early spring temperatures are optimal, the seeds will germinate.
This works best when there is minimal to no competing vegetation in the food plot, and you achieve this by spraying the field with the appropriate herbicide the fall before you frost seed, or by frost seeding a field that was planted in an annual the year before, such as wheat or oats.
You can frost-seed cool-season perennials such as alfalfa, red and white clover, trefoil and chicory, and cool-season annuals like oats, wheat or rye. Do not frost seed warm-season annuals such as corn or soybeans, and while brassicas can be frost-seeded, I prefer to plant them later in the summer. You can frost-seed a new plot or frost-seed cool-season species into an existing plot that is thinning.
Where I live in northern Pennsylvania, green-up occurs in mid-April so the preferred time for frost seeding is generally from late February through March, and I like to frost seed onto a couple inches of snow if possible. This is the ideal frost-seeding time as we typically start getting some warm days that create the necessary freeze-thaw-freeze-thaw conditions you’re looking for. The ideal time for frost-seeding will vary based on your location, from January and February in the South to as late as early April in the Northeast. Study historical weather data to time your planting with the last few weeks of freezing weather in your location, or ask your local extension agent for advice.
When frost-seeding, use the recommended broadcast seeding rate for the particular crop you are planting. For example: 8 lbs./acre for white clover, 15 lbs./acre for red clover, and 20 to 25 lbs./acre for alfalfa. Cut these rates in half if you are overseeding a thinning plot or bare patches.
Don’t forget to amend the soil with fertilizer and lime based on soil-test results. Also, remember that legume seeds like clover and alfalfa must be inoculated with the appropriate bacteria before planting.
You won’t get as high of a germination rate with frost-seeding as you do with more intensive planting techniques, but it’s one way to save some money, and I’ve had great results from frost seeding during the past several years.