There are two cultivar types for you to choose from:

• Tetraploid: four sets of chromosomes
  
• Diploid: two sets of chromosomes
  

Tetraploid types have larger tillers and seed heads and wider leaves. Tetraploid types also tend to be taller and less dense than diploid types, even in early stages of regrowth. They are usually more disease resistant and may be higher yielding than diploid types. Few diploid varieties perform well in the Midwest as they go dormant during mid-summer.

Description:

• Ryegrasses (Lolium perenne L.) are the most popular and best-adapted cool-season grasses in most of the world.
  
• Perennial ryegrass establishes rapidly, is highly palatable, has a long growing season, is relatively high yielding in suitable environments and has high nutritive value.
  
• Grows from 1-2 feet tall with numerous long, narrow, stiff leaves near the base of the plant.
  
• The under surfaces of the leaves are bright, glossy, and smooth.
  Approximately 227,000 seeds per pound

Best Uses:

• Can be used for grazing, hay, or silage.

Adaptation:

• Grows best in cool, moist climates. Optimum growth occurs between 68-77° F.
  
• Perennial ryegrass grows best on fertile, well-drained soils but has a wide range of soil adaptability. Does not perform as well on sandy soils or under drought conditions.
  
• It is tolerant of poorly drained soils and frequently is used in these environments.
  
• Perennial ryegrass will grow on soils with pH of 5 to 8, but forage production is best at pH of 6 to 7.

Management considerations:

• The crop grows well in early spring and fall, but during the hot summer months it becomes dormant. Even with irrigation or abundant summer rainfall, perennial ryegrass production suffers due to high temperature stress when day temperatures exceed 86° F and night temperatures exceed 77° F. It is more sensitive to temperature extremes and drought than annual ryegrass.
  
• Perennial ryegrass is less winter-hardy than orchardgrass and tall fescue and less drought tolerant than smooth bromegrass.
  Longer drying times make ryegrass better suited for green chop, silage, and grazing than for dry hay.

Planting Dates:

• Early to late spring, late summer.
  
• In southern MN: March 15 – May 15, August 1st - August 15th

Seeding Rate:

• 25-35 lbs/acre alone. 6-10 lbs. in mixtures.
  
• Drill ¼ - ½ inch deep in a well-prepared seedbed. Can be drilled (best method), broadcast or bulk-spread and lightly dragged in.
  
• About 14 days to emergence.

Fertility requirements:

• Perennial ryegrass requires high fertility levels for good production. We expect economical responses from applications of up to 150-200 lbs. N/per acre in pure ryegrass stands under adequate rainfall or irrigation.
  
• Applications of total yearly N should be split, as evenly as possibly to reflect the continuing need for nitrogen throughout the growing season taking weather conditions into account. The first application should be applied at the beginning of the season and the others after each harvest or grazing cycle except the last. This application system produces a greater annual yield and better quality forage than does a single, early spring application and results in better utilization of applied nitrogen.

Pasture management

• Perennial ryegrass is ideally suited for intensive sheep and cattle grazing systems as it can withstand close frequent grazing.
  
• New stands of perennial ryegrass should be well-established and approximately 10-12 inches tall before grazing. Ryegrass plants are established when they have three or four leaves. Established stands can be grazed when 4-10 inches tall, but should not be grazed shorter than 2-3 inches.
  
• When rotational grazing is used, pastures should be rested for a minimum of two weeks following grazing, but longer if growing conditions such as dry or hot weather cause slower regrowth.
  
• Yields of perennial ryegrass have been shown to be higher under rotational than continuous grazing.
  
• Frosted ryegrass is susceptible to damage by trampling livestock.
• Livestock and machinery should be kept off ryegrass pastures under late fall or early spring conditions when freezing occurs.

Management for hay

• Perennial ryegrass often is harvested for silage. It makes up a considerable portion of dairy-quality grass silage in many parts of the world.
  
• As with all forage species, silage quality is influenced greatly by maturity stage. For the optimal compromise between quality and quantity, cut perennial ryegrass in the boot stage.
  
• Harvesting perennial ryegrass for hay is not recommended in high rainfall/humidity areas. Good hay curing weather typically occurs too late in these areas for producing high-quality ryegrass hay.
  
• Mowing with a sickle bar is difficult. Ryegrass needs longer curing times before baling.

Perennial Ryegrass
ftp://ftp-fc.sc.egov.usda.gov/

Ryegrass Types for Pasture and Hay
http://www.uwex.edu/ces/forage/pubs/ryegrass.htm