What Cover Crop Should I Plant?

Tips for Southeastern and South-Central Pennsylvania farmers to consider regarding which cover crop to plant.

Wet and Cold, then Hot and Dry, now Wet and Cold again. This year gets my vote as one of the most unusual and challenging in recent history. Last year also started Wet & Cool, and then also moved into Hot and Dry; however, August and September stayed that way giving us an early harvest. Cover crops, alfalfa and small grain seedings were all able to be planted in a timely manner. Not so this year.

The recent rains (this article was written on September 6,) will push silage harvest back another week and have many folks playing catch-up. Those who hoped to supplement low forage inventories with oats or another fall forage may be disappointed. You may be wondering when do I drop more expensive and time sensitive seedings and “Fall” back on one of the cereals such as Rye?

As they say in real-estate “location is everything;” and depending upon your location, the planting window is rapidly closing. Here in the Southeast, we have been known to cheat on many published planting dates. However; the survivability, dry matter accumulation, nutrient scavaging, and less tangible soil building benefits decrease with delayed planting of cover crops.

Below are some tips for Southeastern and South-Central farmers to consider as the planting window begins to narrow in the next few weeks.

  • After Mid-September forget about growing a fall forage (oats) and focus on what your needs will be for the spring.
  • Legumes tend not to grow as aggressively as grasses, after September 15, consider seeding Crimson Clover and hairy vetch with a companion, as part of a mix - or not at all in October.
  • Fertility enhances growth. Dairymen know that planting into a field with a fresh coat of manure is hard to beat. No manure? Consider 30 units of Ammonium Sulfate on predominate grass mixes.
  • October is the month to focus on cereals. Once you turn the calendar it’s time to focus on Wheat, Rye, Triticale, Ryegrass, and Barley. Increase seeding rates as you approach the end of the month.

Can I violate these dates? Yes, you can! I have seen Ryegrass and legumes such as Crimson Clover & Hairy Vetch planted in mid October survive the winter. Sometimes it works well – especially if you want to delay spring planting to allow for increased growth. If you do have a later crop such as Soybeans, Tobacco or Vegetables you may consider keeping a legume in the mix for the Nitrogen and soil building benefits. Finally, we have the moisture! Seeds planted today will be sprouting tomorrow. Heat units however are unknown and often just as critical.

Mixtures which I personally like. We’ve done six years of cover crop plots on farms here in Lancaster County and if you are going to “cheat” a little, these are some to consider - especially if you can allow spring growth to continue until early May.

  • Crimson Clover (15#/acre) & Annual Ryegrass (12#/acre) or Triticale (2 bu./acre)
  • Oats (2 bu./acre) & Crimson Clover (15#/acre)
  • Triticale (75#/acre) & Ryegrass (10#/acre)


There are as many uses for fall seeded grasses and legumes as there are species and combinations. Know what your goals are and what your planting constraints (timeliness, etc.) are. Cereal Rye is the king of winter cover crops for a very good reason. It often meets multiple needs, takes abuse well, and is economical. Before switching to something different know what advantages and pitfalls you may encounter.

Contact Information

Jeffrey S Graybill
  • Extension Educator, Agronomy
Phone: 717-394-6851