Herbicides sometimes get a bad reputation, since many stay in the soil for long periods of time and could be harmful to animals and people. Not carefully applying herbicides can lead to spray drift, which can harm the eyes and lungs of people nearby. However, herbicides still have many benefits.
Successful Weed Elimination
Herbicides kill off weeds that other methods, such as mulching, are unsuccessful at stopping. Also, herbicides can kill specific weeds, while leaving other plants alone. However, spraying too much of a non-selective herbicide can still sometimes kill other plants.
Killing weeds with herbicides removes unsightly plants from the yard, making the yard more attractive. Having dandelions mixed in with perfectly mowed grass can make the grass still seem unkempt. However, herbicides can sometimes accidentally kill some turfgrass.
Herbicides reduce the amount of fertilizer that needs to be added to the lawn, since there will be fewer plants leaching nutrients from the soil. According to CropLife America, herbicides increased crop yields in America by $16 billion and reduced weed control costs by $10 billion. (Chemical herbicides are sometimes beneficial over organic herbicides because they are often more effective and less expensive.)
Some weeds, including certain species of trees and shrubs, are very hard to eliminate. Herbicides are sometimes the only way that these plants can be killed, since some plants are able to send up sucklers and can store a large amount of nutrients in the soil for growth when they need to regrow.
Long Term Prevention
Herbicides can continually kill weeds by soaking into the soil and creating an environment that is not hospitable to them. Herbicides can often spread from one plant to another through interconnected root systems.