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 overwinter on the traditional grass cover crops of oats and barley. This has lead to interest in evaluating broad leaf cover crops. After harvest in 2003, a field was divided into 90’ by 90’ plots. These plots were planted in six different cover crop treatments: Sprint (an oat/cow pea mix), buckwheat, hairy vetch, red clover, mustard and a check of oats. The grower plowed down the cover crops mid winter and in the following spring planted onions in the whole field. Just before harvest, we evaluated for weight, size and number of onions in each treatment. Surprisingly, we found no statistical difference between the various treatments and the check in terms of number of onions, weight of onions and onion size.