Dandelion (Taraxacum officinale) is a perennial weed with thick taproots and serrated or straight edged foliage. The weed blooms with 1- to 2-inch, yellow flowers composed of very narrow petals that turn into puffy seedheads upon maturation. A number of organic control strategies help to discourage the growth of dandelions.
As soon as the weed is spotted, dig it up, removing as much as possible of the thick taproot. Apply mulch made of shredded cardboard over the weed for control. You can also cover the weed with a thick layer of newspaper for the entire growing season, as suggested by Barbara Ellis in Organic Pest & Disease Control.
The use of corn gluten meal is cited as the most popular organic herbicidal control option for dandelion by Patricia Michaels of the Green Nature site. Corn gluten meal is a long-term dandelion control strategy. Corn gluten meal is composed of dried and mashed corn. Spread over weed growth area to retard the germination of weed seeds.
You can use vinegar as an organic weed killer to help eradicate dandelions rapidly. Fill a spray bottle with undiluted vinegar and use to spray the center of dandelion flowers as they bloom. Spray the plant entirely and also near the ground to let the vinegar soak the root area. Avoid application on rainy days as the vinegar will be washed away.