Abstract: An irrigation system for use in a citrus grove. Water is pumped from a well into a chamber of an elongated filter which has an outer casing and an inner treating unit defining the chamber. The filter also has a spiggot and valve for flushing the filter. Irrigation water goes in one end, through the filter, passing from the chamber into the treating unit and out the other end to a main line. The main line supplies sub-main and branch lines to T-shaped pipes which terminate in posts. Each post has a vertical pipe which emerges from the post and has a spraying head designed to be just above the post. The T-shaped pipes are disposed so that the posts will emerge on both sides of a tree trunk and spray water from both sides onto the tree trunk to feed the roots.