With unstable climates and growing populations, there is increasing pressure on agricultural industries to efficiently produce more food. By 2050, the world must be producing 60% more than we already are today. The key to doing this is knowing how to allocate resources, such as water, as efficiently as possible. By being able to sense soil moisture over large areas of land and in real time, farmers are able to optimise their irrigation strategy. Thus, the purpose of this project is to design an L-band radiometer that is capable of remotely detecting soil moisture levels. The radiometer works in conjunction with an L-band antenna, used to measure radiation emitted by the soil. The level of radiation can be related back to soil moisture through a series of algorithms. This project prototypes this system, with aspirations of future designs being applied on an agricultural scale.