Does anyone know anything about gardening?

Awesome! Hedgehogs are my favourite but I haven't seen one in decades and my children never have. I keep meaning to put out some sort of footprint tunnel thing to see if they are about.

I do like the hedgiepigs. Even if I do have to evict them from the garage on a regular basis. They just love sniffing solvents. And eating spiders. I think I need another pair of welding gauntlets just for shifting hedgehogs. Of course I could just try shutting the side door to the garage at night, but history strongly suggests I just don't have the discipline to do that reliably. The only downside is that they are bloody noisy during mating season. Much snuffling. Very heavy breathing.

Does trying to block cats from going under do much? Wouldn't they just go over?

They do get over, but I'm working on that. Apparently putting shards of broken glass on the top of garden walls is no longer socially acceptable, but I view cats in the same way as I view burglars - you can't guarantee to keep them out, but you can at least make life hard for the evil little fuckers.