Some plants are very sensitive and need constant care. Unless our work is to watch out for plants, we cannot be always there and ensure perfect conditions. So at least for most sensitive we can build a bot that would look after it. Appleman123987 have built good looking planterbot which always keep an eye on plant and displays on LCD when something is needed.
Planterbot is based on Arduino Uno which reads plant environment parameters: Thermistor reads surrounding temperature, Cds photocell reads light and moist sensor out of aluminum foil reads water level in soil. The case of planter bot is made of laser cut plywood with cutout for LCD and aluminum moist sensor. No wires are poking out (except USB cable for power). Moist is measured at the bottom. If there were watering ability, then it would take care of plant even better.