Over my many years as a self-identified Pagan, I have had the opportunity to work with a number of different ways of protecting ritual spaces.
While many Wiccan circles define a firm boundary to the ritual space, there are many other traditions that don’t. Even the traditions that do have the firm boundary sometimes don’t have it all the time.
So, why do you define the boundary or not? Well .. there’s a lot of “it depends.” In most cases that I’m aware of, the firm boundary is designed as much to hold IN energy as to keep negative influences out. When you’re doing focused magic or intense work, this can be very useful. However, there are other times where it’s not as important to hold the energy in .. or even preferred to allow the energy to spread out gradually. In public rituals especially, it can be very useful to have a flexible or permeable boundary. Parents feel more comfortable bringing their kids if they can quickly leave if the kids don’t want to be there, or people can go if they need to go to the bathroom. And if you’re at an outdoor festival, not having to worry about the adults or children who wander late to the ritual crossing your boundary is very useful!
In ADF, our public rituals don’t have firm boundaries. Since our public rituals are mostly devotional, this works out great. We want the natural world to interact with us during the ritual. We do, however, make sure to protect the space that we’re working in – while we want beneficial, or even neutral, outside influences, we do want to keep out the negative influences. As part of our rituals, we call upon a Gatekeeper – an other-worldly being who we call, make offerings to, and ask to protect the space. Also, many of our rituals make an explicit call to these negative influences – what we sometimes call “Outsiders” to leave us alone. Ritualists in other traditions will often do similar things for rituals where they don’t have a firm boundary. They will either call upon an other-worldly being or will take other specific actions to protect the space without requiring the firm boundary.
There is no “right” way to protect the boundary of your ritual space. The type of protection that you should use is very dependent upon your physical, magical and spiritual circumstances. Sometimes you really want that firm boundary, sometimes you really don’t .. and most of the time you’re somewhere in the middle. Think about what you’re doing, and experiment. Find what works for you.