Although it may be a dim memory at this point, we started the 2016 growing season on the wet side. Some planned spring forage seedings did not happen due to wet conditions and a compressed spring planting season. Add to this the fact that some alfalfa stands are not holding up as planned because of harvest injury during the wet and rainy conditions of 2015 and now the dry summer conditions of 2016 and there are potentially a lot of acres of alfalfa or other perennial forages that need to be planted as we look ahead to 2017. August provides another window of opportunity to establish a perennial forage stand.
Typically the main risk with an August planting is sufficient moisture for seed germination and plant growth and it looks like this year will not be an exception, as the weather outlook for August is for rainfall to be below normal. Most of our perennial forage grasses and legumes are shallow seeded crops and should be planted no deeper than ½ inch and ideally closer to ¼ inch. If the seed bed is too dry germination and emergence will be poor. This year’s weather pattern needs to be considered and planting may depend upon a favorable forecast for rain. As I write this, our Wayne County area and all of northeastern Ohio, are under moderate drought conditions according to the USDA drought monitor web site. Keep in mind it is best to plant into moist soil or right before a large rain system is forecast.
There are some advantages to late summer forage planting as compared to a spring planting. One big plus is that planting time and field preparation is not competing with corn and soybean field work. No-till planting following a small grain crop often works well. Late summer planting means forage seedlings are not competing with the flush of annual spring and summer weed emergence/growth. The soil borne root rot and damping off disease organisms that thrive in cool, wet soils are not an issue.
Ideally, planting should be completed by mid-August in Northern Ohio and by the end of August in Southern Ohio. These timelines are based on average frost dates and the time needed for forage plants to develop a root system capable of overwintering. For example, at about 8 to 10 weeks after emergence alfalfa plants pull the growing point below the soil surface, a process is called ‘contractile growth’. Once contractile growth occurs the alfalfa plant is considered a true perennial. The alfalfa plant needs to reach this growth stage to overwinter. Clover plants also need to have a crown formed, and grasses should be at least in the tillering stage of development before the onset of winter. If the fall is warm and extended, similar to what we have experienced the past few years, later planting dates can result in successful establishment. Some alfalfa growers believe that the late summer planting deadline dates can be moved back by several weeks due to climate change and longer falls. Just keep in mind the unpredictability of weather.
In a no-till situation, minimize competition from existing weeds by applying a burndown application of glyphosate before planting. Post-emergence herbicide options exist for alfalfa. After the alfalfa is up and growing, late summer and fall emerging winter annual broadleaf weeds must be controlled. A mid- to late fall application of Butyrac, Pursuit or Raptor and Buctril are the primary herbicide options. Fall application is much more effective than a spring application for control of these weeds. Pursuit and Raptor can control winter annual grasses in the fall but should not be used with a mixed alfalfa/grass planting. Consult the 2016 Ohio and Indiana Weed Control Guide and always read the specific product label for guidelines on timing and rates before applying any product.
When tillage is used to prepare the soil for planting, a firm seedbed is needed to ensure good seed-to-soil contact. Follow the "footprint guide" that soil should be firm enough for a footprint to sink no deeper than one-half inch. A pre-plant herbicide is not needed for a tilled seed bed. Generally, the risk associated with establishing a tilled seed bed for a late summer planting is the loss of moisture. Finally, keep in mind the importance of soil fertility and pH. The recommended soil pH for alfalfa is 6.8. Forage grasses and clovers should have a pH of 6.0 or above. The minimum or critical soil phosphorus level for forage legumes is 25 ppm and the critical soil potassium level is somewhere between 100 and 125 ppm for many of our soils.
Contact the Wayne County Extension office at 330-264-8722 for more information about forage establishment.