First things first: Building a DIY greenhouse with old windows will vary from project to project. The process depends a lot on the size of the windows you source, as well as the area that you have for your greenhouse. Therefore, I’m not going to include any measurements with this post. This is going to be a helpful tips and tricks sort of post, as well as a divulgence of costs post. If you have any questions, feel free to leave them down in the comments below.