Answer: Crimson clover is an attractive, soil enriching legume, best seeded in the early fall. It, like many clovers, will cast seeds into adjacent lawn areas. The main factor however in my opionion is that it takes up most of the spring gardening season if you wait for it to bloom and fix nitrogen in the soil. This going to be true of all cover crops, or "green manures" as they are often called. Gardeners use it and other cover crops on areas they aren't gardening that season. With just 120 sq. ft., can you spare the space? A better approach may be to compost and add the finished product to build your soil.
Another cool season cover crops used by gardeners is vetch. For warm season you could try southern peas or peanuts. Although not that attractive, they offer a good harvest and build soil.
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