I have had several emails and weed samples submitted recently of an unknown grass. In each case, the sample was annual ryegrass (Lolium multiflorum).
Annual ryegrass is a common ingredient in low quality seed mixtures. It appears in the spring time in lawns seeded the previous year either from some annual ryegrass in the seed mixture or from some seed in the soil. Annual ryegrass is a winter annual and it should die later this summer when it gets hot. Before dying, it produces a seedhead and its seed can mature quickly and drop to the soil where it can germinate the following fall. No control is recommended as it is an annual grass.
To reduce the likelihood of this weed being problematic in the future choose a seed mixture that does not contain annual ryegrass, Italian ryegrass or intermediate ryegrass and one that has no weed seed. If you have this problematic weed each spring, make sure to mow the grass before it can produce a seedhead to help reduce the likelihood that it will return.
For more information on differentiating annual ryegrass from winter wheat, a similar looking weed that also shows up this time of year in lawns seeded last fall, see this turf tip posted last year: Grassy Weeds in Turf Planted Last Fall.
Dr. Aaron Patton, Turfgrass Extension Specialist