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Agronomic Crops Network

Ohio State University Extension


Don’t leave your fields naked if taking the prevent plant option on corn and soybean ground – Farms underwater won’t have a choice but farmers still have options.


It’s been a rough spring for much of Ohio and the counties that have received the most rainfall typically have less than 20% of the county planted. Many unplanted acres remain across the Corn Belt and in Ohio. The decision to plant or not to plant still lingers in a farmer’s mind. Farmers truly want to plant but with the June 20 deadline for planting soybeans or declaring prevent plant, many farmers will be taking the prevent plant option. Additionally, on the acres not planted, weed pressure is becoming more and more of a problem.  

Prevent Planted fields should not be left bare/naked. Without competition for sunlight, weeds will continue to germinate and grow to create a weed seed back for many years to come. Soil erosion on bare soil can occur even on flat fields. Therefore, make a plan to prevent planted fields: control weeds first to prevent seed set, if the soil surface is uneven, then tillage should only be done when soil is dry to avoid compaction. Cover crops can then be sown which will protect the soil until 2020 crop planting.

Prevented planting rules and guidelines should be reviewed and can be found in the Risk Management Agency (RMS) website document, Prevented Planting Insurance Provisions Consult your Farm Service Agency (FSA) and crop insurance agent when considering options for prevented planting acres.

Cover crops can be a good way to take advantage of an otherwise unfortunate situation. A full season cover crop is a great opportunity to improve soil health and function. Cover crops can help to reduce soil erosion and compaction, capture nutrients, fix nitrogen, suppress weeds, moderate soil moisture, and build soil health. Benefits accomplished with these cover crops will put farmers at an advantage for the following cash crop and for years to come. A full season legume cover crop can provide considerable nitrogen for next season’s corn crop. This is also a good opportunity to capitalize on the benefits of a diverse cover crop mix. Mixing species is a good way to compound the benefits from multiple species. Many of these benefits will lead to increased soil resiliency (the ability for soil to adjust to climatic or practice changes) in the coming years.

As with typical crop planting, make sure to plant when field conditions are fit. Fieldwork under wet soil conditions can impact soil function for years to come. The growing window for cover crops is an opportunity in 2019.  


When looking at the selection of cover crops, there are 3 main categories/options of species to select from.Crimson Clover

  • Grasses (oats, annual ryegrass, winter cereals, and summer grasses) build soil organic matter quickly while generating the most above and below ground biomass. Oats can be planted at any time outside the winter months and is the least cost option. Be aware that the heat of summer is not ideal for oats, but they can still be successfully utilized. Oats can be drilled at 30-60 lbs. per acre and at a depth of ½ to 1 ½ inches. If you are looking for weed control, summer grasses like sorghum-sudangrass is a good option. Sorghum-sudangrass can be planted early summer. Summer grasses will winter-kill, but their residues will continue to provide some protection through the winter and next spring. Winter cereals and annual ryegrass are another option but realize when you planted them early they may not perform the same as when they are planted later in the season. Winter cereals and annual ryegrass can be planted mid-to-late summer and are winter hardy requiring termination next spring.
  • Legumes fix atmospheric nitrogen providing a source for next year’s crop. Red clover or berseem clover can be planted early summer, while for late summer planting consider crimson clover, sweet clover, hairy vetch or winter peas.
  • Non-Legumes Broadleaves (Brassicas), such as radishes, mustards, and rapeseed, have taproots to break up compaction and improve permeability plus are also excellent nitrogen scavengers. Brassicas can be planted late summer. Planting radish before August can result in bolting and going to seed, limiting the size of the taproot. Mowing can be used to help prevent bolting in some cases.

Summer annual cover crop species are ideal to prevent plant situations, but each come with their own concerns. Cool season cereals such as rye, wheat, and barley planted in the heat of the summer will not produce as much biomass, may not overwinter successfully, and will be at increased disease risk.

There are reasons to look beyond these species to meet your cover crop needs. A few of these considerations are listed below.

  • Cover crop seed availability is limited for many species. Contact your seed dealer to find out what species are available and affordable to you.
  • Teff is small seeded and does well when planted with a Brillion seeder or cultipacker.
  • Sunn Hemp thrives in warm climates and will have more nitrogen benefit in southern regions of the Midwest.
  • Sunflowers are susceptible to white mold.
  • Buckwheat is successful in a short timeframe but goes to seed quickly.

Specific questions can be directed to those who specialize in cover crops such as Extension Educators, Cover Crop Seed persons and even your experienced neighbors who have been using cover crops for years.


SorghumDo your homework when selecting a cover crop. Look at what you are trying to do in your field while selecting the cover crops and how cover crops might help you this year. Be aware that planting some species out of season is not ideal. Some cover crops are sensitive to some residual herbicides. If you have already applied residual herbicides, consult herbicide labels for plant back restrictions (see Resources). While the resources below have general guidelines, note that farming practices vary from farm to farm. 

  • Managing Weed Pressure – If you are planning to use cover crops in fields with heavy broadleaf weed pressure (i.e. marestail, waterhemp, etc.), consider using a grass species as a cover crop so that broadleaf herbicides can be utilized to manage weed populations over the summer.
  • Seed Availability – If summer annual cover crop (listed above) seed availability is low, you might consider controlling weeds until August and then planting a cool season species or mix.
  • Grazing/Forage Harvest – Discuss insurance details and payments with your agent. Cover crops may be harvested/grazed after November 1, or harvested/grazed before November 1 for partial payment on prevented plant acres.
  • Residual Herbicides – Consider herbicides that may have already been applied in anticipation of cash crops. Refer to herbicide labels for details. Brassica and legume cover crops can be especially sensitive to residual herbicides.
  • Preparing for Wheat – If you plan to plant wheat this fall, a cover crop that fits in a short window and produces nitrogen is ideal. Cowpea and Mung Bean are legumes that are appropriate for a short window in the summer months. Wheat contaminated with buckwheat seed can affect export to Japan. Other cereal crops such as rye can also be a problematic contaminate in wheat.

Using Cover Crops as a Forage

Additionally, when looking at a cover crop for forage for livestock, definitely look to the clovers as an option for forage. Sorghum-sudangrass and some summer grasses are other good options. The use of cover crops as a forage opens a different set of species can be used that are not typically considered for cover crops. These species are cover crops such as Teff or the millets. The caution is if you are looking for cover crops as a forage and you are taking a prevent plant insurance option first consult with your crop insurance agent for restrictions. Many of the plant species that can be used could also be used for grazing and harvested for feed. RMA has strict rules regarding grazing and haying specifically:

  1. Plant a cover crop during or after the late planting period and do not hay or graze this cover crop before November 1 to receive a full prevented planting payment.
  2. Plant a cover crop during or after the late planting period and do hay or graze this cover crop before November 1 and receive no prevented planting payment.
  3. Plant a cover crop after the late planting period and do hay or graze this cover crop before November 1 and receive 35 percent of a prevented planting payment for your first crop.   

References and Additional Resources

Cover Crop Considerations for Prevent Planting,

Managing Cover Crops Profitability, 3rd Edition,

Midwest Cover Crops Field Guide, second edition,

Midwest Cover Crops Council,

Midwest Cover Crops Council Selector Tool,

Prevented Planting Standards Handbook, 2019 and Succeeding Crop Years; USDA,—25000/Prevented-Planting/2019-25370-Prevented-Planting-Standards.ashx?la=en

Corn Herbicide Carryover Table; Penn State University Extension,

Soybean Herbicide Carryover Table; Penn State University Extension,




Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.