If I set my red eared slider turtle free in the spring into a lake that has a lot of other turtles will it adjust well and will it grow in size once it becomes free?

Make sure your turtle is in good health and knows how to catch its own food. Put a few feeder fish in its tank and make sure it knows how to catch them. Mostly your turtle will eat vegetation, but being able to catch its own food is a good skill to have. Most importantly, make sure you can legally release your turtle on the property. If its private property, check with the owner. If its a state park, check with the ranger. You don't want to add one more problem to a lake already overrun with unwanted turtles. Good luck. Make sure your turtle is in good health and knows how to catch its own food. Put a few feeder fish in its tank and make sure it knows how to catch them. Mostly your turtle will eat vegetation, but being able to catch its own food is a good skill to have. Most importantly, make sure you can legally release your turtle on the property. If its private property, check with the owner. If its a state park, check with the ranger. You don't want to add one more problem to a lake already overrun with unwanted turtles. Good luck.