Hey @RowanM, welcome to the forums! 
So the auto-watering was planned to be from a reservoir hidden away somewhere - perhaps in a cupboard or underneath a desk. I’ve got the float switch to monitor when the reservoir is empty and needs attention, and the peristaltic pump to push the water up to the plant.
With the current plan you’d need a 5V power supply per plant, which could either come from a mains adapter, or a good USB battery bank would do the trick, although I’m not sure how long the battery would last until we can complete a prototype and take current measurements.
Thanks for following along!