Crabgrass is indeterminate and can produce new tillers and ripen seed simultaneously from June to fall. These characteristics allow crabgrass to produce a seed bank, which consists in seeds in and on the soil for the next season's volunteer stand. Via controlled residue height and recovery period, sufficient shatterable seed can develop; 1/4 to 1/2 teaspoonful per square foot is acceptable.

Hay should be cut to allow some seed shatter during harvest. Uncut strips can be left between swaths so that their seed can ripen before the next harvest.

Crabgrass grows best when temperatures are about 80°F to 100 °F. The soil temperature at 2 to 4 inches deep should be above 70°F. Crabgrass is moisture-loving but does not perform well in soils that are supersaturated for long periods. It grows well with 24 to 60 inches of rainfall if other conditions are acceptable but produces sporadically if rainfall is below 20 to 24 inches. It has good drought tolerance. In June, July, and August of 1993, there were approximately 60 days without rain, but crabgrass survived. In 1980, southern Oklahoma experienced record hot dry weather and had approximately 100 days without rain and 60 days of 100°F or hotter temperatures. Crabgrass produced about 1.5 tons per acre before the drought, but over 90 percent of the plants were dead by the time it rained in the fall. During 1998, from April 1 to October 1 west central Oklahoma experienced the worst drought since record keeping began in 1901, a span of 97 years. The light showers received produced a crabgrass stand for ground cover and stands persisted well, but yields were very low.

Producers advise that crabgrass tolerates salty conditions better than bermudagrass. It does not, however, tolerate strongly alkaline soils, nor does it produce well on soils with moderate to strongly basic pH. A pH of 7.5 or above is cause for alarm, although some good yields are on soils with a pH of 8.0 or higher.

Crabgrass produces best at a day length of twelve hours or more; the longer the day, the better the production. The order of crabgrass's preference for soil texture is sandy soils, loams, silt loams, and clay loams. Crabgrass performs very poorly or not at all on very tight clay loam, pure clay, and silt soils or silty clay soils.

Geographically, crabgrass grows well over all of Oklahoma except the panhandle, where its dry-land production is relatively low and sporadic. Naturalized crabgrass grows in every state in the contiguous United States and in subtropic, mild, and temperate climates throughout the world. As useful forage in the United States, its geographical adaptation is primarily from west central Nebraska to the Texas coast to the Eastern Seaboard. Secondary adaptations just north of that area can produce excellent crabgrass forage but in a compressed summer season of perhaps 45 to 60 days.

The Noble Foundation, Ardmore, Oklahoma, has done considerable work with crabgrass forage and produced numerous publications. The following publications are summaries of some of that work.

Dalrymple, R. L. 1975. Crabgrass as a forage. Pub. No. CG-75. The Samuel Roberts Noble Foundation, Agricultural Division, Ardmore, Oklahoma.

Dalrymple, R. L. 1983. A summary of research and demonstration about using crabgrass as a forage. Pub. No. CG-83. The Samuel Roberts Noble Foundation, Agricultural Division, Ardmore, Oklahoma.

Dalrymple, R. L., J. L. Baker, and J. S. Swigert. 1991. Crabgrass seminar and field day report. Pub. No. NF-GE-91-01. The Samuel Roberts Noble Foundation, Agricultural Division, Ardmore, Oklahoma.