The present invention is directed to a horizontally extendable silt fence. The present invention is also directed to a silt fence system comprising a horizontally extendable silt fence comprising a water permeable geotextile material having an upper edge and a lower edge, and a plurality of posts comprising an upper portion strutted and arranged to be coupled with the upper edge of the water permeable geotextile material, a lower portion structured and arranged to be coupled with the lower edge of the water permeable geotextile material, and an anchor portion structured and arranged to be driven into the ground to anchor the post. Also disclosed is a method of filtering silt from a fluid stream.