The following question was sent to the P&PDL diagnosticians here at Purdue University:

Question: What do you think of a cover of black plastic as a long term solution for getting rid of Crabgrass?

It takes a long time to see results, but does seem to work.

Answer: I'm assuming you would use the plastic over the lawn to kill the crabgrass with heat? This will only kill the living crabgrass and will not kill the seeds in the soil. The large store of crabgrass seeds in the soil will allow for germination next spring. Also it will kill any turfgrass that might be on the lawn. I don't think it is a good solution for controlling annual weeds in a lawn. Mowing as high as you can, fertilizing primarily in the fall to create a dense lawn, proper watering, and possibly a preemergence herbicide in the spring are the best ways to control crabgrass.

--Zac Reicher, Assistant Professor/Turfgrass Extension Specialist

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