I received an email from a reader asking about replacing heads. Here is my reply:

I had to replace a head not too long after making my first installation, and it was fairly simple. When the ground was slightly wet around the head, I pushed the head side-to-side and back-and-forth to wallow-out some room around it. Then, I used a large wrench to grip the widest part of the head and unscrewed it. (Alternatively, you can just use your hands if you’re able.) When I had the replacement, I simply screwed it back in.