How do you get ripples out of artificial grass?

Well it depends when you get the ripples issues. If you see the ripples at the time of installations, that means your installer need to do a better job. It is normally required for a professional installer to have basic installation tools such as carpet stretcher. At the installation of artificial grass, installation start from one end, once the end edge is secured, installers need to your the carpet stretcher to knee kick the ripples out of the way as they moving along to the other end: this is very similar to a carpet installation, knee stretchers to take out of the ripples.

If the ripples happen after the initial installation, which could be caused by turf's expansion/contraction due to the temperature changes: this problem also will trace back to the installations. At the initial installation, all edges needs to be secured, and seams to be done properly and infills to be used to give more weight to hold the turf down solidly. If such installation requirements not met precisely, turf can move, pulling off the adages, or separating the seams or twisting within certain areas, then you will see the ripples. 

Under normally circumstances when professionals used for proper installations, ripples on turf won't happen. If you ever experience the issue, we will suggest you to find a professional installer to help fixing it: sometimes it will require to pull out the entire piece and reinstall it properly.