I needed a solid way to hold my ¼" irrigation sprinklers in place so they could be directed into the flowerbeds, so I designed these 5" spikes to hold the risers in place.  You assemble your riser and sprinkler head and then just press fit them into the spikes so they can be held firmly in place.

I have printed them in PLA, and PETG, but ASA (Like the photo) is a better choice for outside use exposed to full sun.

I have printed on multiple printers including a CR30 belt printer and seems to work well on all. I suggest printing with a high level of infill for strength when you are shoving them into the ground.