OK so I am new to brewing at home and I put peaches in my secondary .They were mashed and brought up to 170 and cooled down then pitched in secondary my question is how long do I leave them there before bottling??
That is completely up to you! I would taste test every 3-5 days until you get the taste you are looking for and bottle.
Something to remember is you might kick off a secondary fermentation so just to be safe I would check the gravity again and make sure your FG is stable before packaging you don't want any bottle bombs!
At least 2 weeks. Let them fully ferment out, or you'll have exploding bottles. After a week or so, take a reading, and then every 3 days afterwards. Once you have a stable reading twice in a row you can safely bottle.