I used the design by Double_Alfa to make a planter from the head. It will require dual extrusion to print.
Apart from the hole in the head, I also modeled a water reservoir in the neck with an overflow tube. The plate will keep substrate above it, but in contact with the water so the soil keeps moist. This system keeps the plant moist without giving it water every day. I do recommend to put a drinking straw in, from the top down to the reservoir before adding the substrate, so you can fill the reservoir directly (I couldn't find a good spot to model it in, it took too much space, or a lot more then a drinking straw would at least). I would also say to be careful to monitor the plant the first few days, as the new substrate will suck up a lot of water before there's an equilibrium.
And finally I've added a dripping tray, to be printed with dual extrusion as well. It's optional though.
Just to be sure, I've added a few files with the merged head and tray as well.
Big print, the head took 1,5 days for me to print.