Cover Crop Species to Plant Mid-September

Corn silage harvest has already started and very soon high moisture corn and early corn and soybeans will start too. Cover crops are especially key after corn silage to protect the soil from erosion, remediate soil compaction caused by harvest traffic, have a living root to make soil resist manure spreading traffic later, be able to spread manure over the fall and winter so nutrients are not going to waste, provide weed control, and possibly use some of the cover for forage or grazing purposes. But they are also important for the same reasons after other crops. For success with cover crops, timeliness is key so you should have the cover crop seed on hand and the drill ready to go with an operator in the seat when you start your harvest. It gives a lot of satisfaction to see the drill in a field that is being harvested!

While there are still quite many options for cover crop species to be planted in the south, the options are getting fewer in the northern parts of the state as can be seen in the table below. You will notice no warm season annuals (such as millets, sorghum and sudangrass, cowpea, sunhemp and buckwheat) are listed because temperatures are already too low to plant those. Some choices still available in the south are annual ryegrass, crimson clover, hairy vetch and rape – it is already too late to plant those further north. So you are down to the winter-hardy cereals in much of the state very soon. The benefits of planting oats and radish at this time are already questionable anywhere in the state because their growth will be limited before they winterkill. The recommendations in the table are based on research done without manure or fertilizer. Our experience tells us that if a field has higher fertility, planting dates can be relaxed a bit – it is likely that 2 weeks later planting than what is listed in the table can still be successful in that scenario.

Planting date recommendations for fall-established cover crops in Pennsylvania

* Will winterkill throughout Pennsylvania

This material is based upon work supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, through the Northeast Sustainable Agriculture Research and Education program under subaward number ONE16-287c./p>