Answer: Crabgrass is an annual weed that grows from seed each year. It begins to germinate in early spring about when the forsythias bloom. If you want to use a pre-emergent control you could use corn gluten. Read and follow the label directions.(This will also prevent desirable grass seed from sprouting so you might want to consider doing a thorough soil preparation job and then laying sod for more thorough lawn repair.)
Based on your description however I am not certain the plant is actually crabgrass. It may be a nutsedge or some other type of aggrassive grass. You might want to consult with your local Penn State county extension to identify it for certain and get their control recommendations.
They should also be able to help you devise a lawn maintenance program to help keep the desirable lawn grass as healthy as possible. This is your best defense against weeds.
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