As the world faces a changing climate, agriculture needs to develop more efficient and sustainable food production systems. Traditional farming methods consume considerable amounts of energy and are largely manually controlled, which leads to sub-optimal production. Greenhouses, which enable yearround crop growth, can play an important role in efficient food production. Leveraging the need for artificial light in greenhouses when the natural sunlight available is not sufficient, we envision that recent progress in Internet of Things (IoT) technology, together with novel Light-Fidelity (LiFi)-based methods have the potential to significantly reduce energy and resources used in food production. In this paper we describe our work towards sustainable and precision greenhouses by using LiFi-enabled IoT. Here we present a battery-free wireless network of IoT sensor nodes that exploit LiFi for both communication and power harvesting, while monitoring environmental conditions for optimal greenhouse operation and plant production. We highlight the research challenges and the way forward to integrate LiFi to monitor and control greenhouses, as well as a proof-of-concept LiFi-enabled IoT system for a real-world greenhouse.