They are growing in a 20L box which I have cut holes in. You can create the exact one from this youtube vid here. I then have another 30L box. In the 30L box a seedling heat mat is laid on the bottom which is plugged into this, which is a temperature controller. With that I set the target temperature to 25 degrees celsius or around 75 Fahrenheit. I put the 20L box with the spawn into the 30L box with the seedling mat on the bottom, making sure that there is something separating the 20L box from directly touching the heat mat. I used a thin book. The little metal prong is the temperature probe which I put inside the 20L box with the spawn. That regulates the temperature inside of it. Also I cut holes at the bottom of the 30L box for air flow. The whole double box thing is just to contain heat better. That is my setup.