Improve summer pastures with crabgrass

By Michaela King

After being brought to the forefront by studies done at the Noble Research Institute (Ardmore, Okla.), crabgrass began gaining favor as a high-quality forage alternative. Many farmers are now considering it for improving summer pastures.

In an Arkansas Dairy e-News article, John Jennings, an extension forage specialist with the University of Arkansas (UA), notes crabgrass is a warm-season annual and, depending on rainfall, produces 2 to 5 tons of dry matter per acre. Crabgrass hay is typically better quality than other summer annuals such as bermudagrass and pearl millet, and an Arkansas study showed common crabgrass retains its quality even as the plant continues to mature.

How and when to plant

Plant crabgrass mid- to late-spring for the best forage production. Since its yield is dependent on rainfall, avoid planting after mid-summer. Jennings notes, “Crabgrass tolerates drought, but planting on sites that aren’t excessively droughty will result in the greatest forage production.”

Crabgrass seed is hairy and doesn’t flow well through drill seeders. Some seed companies, however, sell coated seed, which helps it flow better through planters. When planting with a drill, keep in mind that planting too deep is more of a concern than too shallow; plant about ¼-inch deep into the soil. When broadcasting crabgrass, spread it onto a tilled, well-firmed seedbed and cover with a second pass using a roller, the specialist advises.

“Most seed will germinate within a few days, but some may germinate over a period of two months,” says Jennings.

He also suggests using nitrogen fertilization when needed. Apply it in two applications of 50 to 60 pounds per acre for each grazing or hay harvest.

Crabgrass works well as a forage when planted with small grains such as cereal rye and wheat. The small grains provide forage for late fall into spring, and the crabgrass fills in during the summer and early fall to provide high-quality forage.

Jennings recommends light tillage when the cereal forage is done being grazed on in the spring. This improves seed germination and promotes better volunteer crabgrass stands for the summer.

Graze or harvest

Crabgrass responds well to rotational grazing. Begin grazing when it is 4 to 6 inches tall, which typically occurs 40 days after seedling emergence. According to Jennings, crabgrass is palatable and animals in a new pasture tend to graze on it first. However, Jennings notes, “Crabgrass becomes very unpalatable after a killing frost and is usually avoided by animals grazing. Plan to use grazeable forage before frost occurs.”

Jennings recommends cutting crabgrass for hay in the boot to heading stage (normally 18 to 24 inches high), which will allow for at least two harvests per year. Regrowth is supported by remaining leaves and not by stored root and crown reserves, so avoid cutting crabgrass lower than 3 inches.

Learn more information about crabgrass in UA’s publication, Crabgrass for Forage.

Michaela King

Michaela King is serving as the 2019 Hay & Forage Grower summer editorial intern. She currently attends the University of Minnesota-Twin Cities and is majoring in professional journalism and photography. King grew up on a beef farm in Big Bend, Wis., where her 4-H experiences included showing both beef and dairy cattle.