Fiesta is an Iron-based selective bio-herbicide with low toxicity that controls weeds, moss & algae on commercial and residential lawns, golf courses, parks, rights of way, schools and playgrounds. We tested out this product on some dandelions and had some great results. 

Before: 

After: 

This second photo was taken only two days later! You can see that it works fast and that it was harmless to the grass around it. Fiesta is highly recommended by many and has also been given a five star rating by many. Be sure to check out this product and learn more about it here Fiesta Turf Weed Killer