The present invention relates to the field of agriculture. More particularly, the present invention relates to an irrigation system comprising (a) at least one water tank disposed beneath a soil medium for supporting plant growth, wherein the water tank contains at least one fibrous capillary tube configured to supply water from the water tank to the soil medium; (b) a water control tank configured to control amount of water in the water tank; (c) a water supply source in fluid communication with the water control tank for supplying water thereto; (d) a water regulating means for regulating amount of water being transferred from the water supply source to the water control tank; a sensing module comprising a first sensor disposed within the soil medium for detecting soil moisture, and a second sensor disposed within the water control tank for detecting water level therein; (f) a monitoring module configured to determine a reference evapotranspiration; (g) a processing module operably connected to the water regulating means, sensing module, and monitoring module, wherein the processing module is configured to convert the reference evapotranspiration to a crop evapotranspiration based on a crop coefficient, apply a predictive algorithm to obtain a predicted optimal water depth based on data collected from the sensing module, the crop evapotranspiration, and a set of historical data stored in a data storage, determine a control action based on the predicted optimal water depth and a set of constrain values, and provide the control action to the water regulating means, whereby the water regulating means regulates amount of water being fed from the water supply source to the water control tank based on the control action.