I print these at full size for plants sown directly into a garden bed, or rescale the X and Y to 75% for those in pots ( I leave the Z at 100% though to create a sturdy stake). No support needed.
I've printed these in white PLA, 2 perimeters with 15% infill and even after leaving them stuck in the ground for 4 years now, they are still looking like new.
The author hasn't provided the model origin yet.