Hi, Cherry. A recommended procedure is to let the wood weather for a minimum of 6 months, then apply a primer of Zinsser Bull's Eye 1-2-3 Primer Sealer. You can then paint with about any type of exterior paint. This should seal the pressure treated wood with the water based acrylic sealer. A much bigger concern is that the baby should never be allowed to put his/her mouth on or chew pressure treated wood. Enjoy the lawn until he/she is past the chewing stage, but be careful of lawn chemicals too.