Polymeric joint sand is designed to harden when installed. This
will inhibit weed growth and virtually eliminate maintenance.
If you decide to use polymeric sand, make sure you have a good
fill in the joints, then use a blower on low setting to blow out
of the joints to a level about 1/4" below the top of the paver.
(When you mist the polymeric sand, a glaze will come off of
it. Having the sand slightly below the surface of the pavers
will ensure that the glaze does not adhere to the pavers.) Mist
the pavers with a hose. Wait until the edges of the pavers start
to dry, then repeat. Repeat 3 or 4 times. Polymeric sand MUST be
installed on a dry day.