The best candidates for artificial weathering are those with many nooks and crannies, such as this basket-weave planter. You will need acrylic paint in white, lime green, and moss green.
Weathering Plastic
A simulated patina helps faux-clay plastic pots blend in with those made from real terra-cotta.
Martha Stewart Living, March 2002
http://www.marthastewart.com/272266/weathering-plastic
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