im not sure, but i found this online

Savvy U.S. marijuana growers have learned never to cultivate more than 49 plants at a time. That rule has nothing to do with horticulture. Under federal sentencing guidelines, each plant in a garden with 49 or fewer plants is considered equivalent to 100 grams of dried marijuana. In a garden with 50 or more plants, each counts as 1,000 grams.

and norml says 1-200grams is a minor misd....so, does that make one plant okay?