Many onion fields have been in continuous, unbroken production for decades. Insect and disease populations build up when no rotation is employed. Over the last few years, onion bulb mites have increased as a problem. Some growers suspect mites over-winter on the traditional grass cover crops of oats and barley. In 2001, we planted and evaluated five different fall planted broad leaf cover crops. The fall planted covers we looked at were annual crimson clover, field peas, yellow mustard, hairy vetch and buckwheat. Two growers in the onion growing region of Orange County and one grower from Oswego participated in those trials. Fields were one acre, divided into one-fifth of an acre plots. We evaluated ease of establishment, root depth and bio mass. Growers were favorably impressed with the yellow mustard and the field peas. Yellow mustard for it’s quick establishment and field peas because it continued growing well into winter and established a dense ground cover.