Devils Advocate wrote:

not sure about that, I've seen grass grow through pavement in the
past. "m Ransley" wrote in message
...
The grass will just die on it own


The key here is sunlight. Grass can easily grow in the cracks of
asphalt and not under the dark of a deck. This is of course a little
dependent on how you build your deck. If you want to be sure, just get
any of the good grass killers that kill the root. This should do the
trick.