Orchard grass is a perennial grass that grows tall and rapidly. It can grow in soil conditions ranging from poor to good, in the shade or full sun. If you don't want to use herbicides to get rid of it, you can use vinegar to eliminate the grass. Using vinegar to kill orchard grass is a simple process that can be accomplished with a few materials and about an hour of your time.
Locate where the orchard grass is growing on your landscape. It is usually tall, with thick stems and a wheat-like appearance on top.
Fill a spray bottle with white vinegar. Do not dilute it. Measure out about 2 cups of the vinegar for every square foot of orchard grass.
Soak the grass with the vinegar spray from the bottle, targeting the orchard grass within a couple inches. You want to saturate it completely.
Keep an eye on the orchard grass after applying the vinegar. It should start to die within a half hour, and should be completely dead within two days after applying it. If it is still alive, repeat the process.