Herbicides are any types of chemicals or products designed for the purpose of killing undesirable plants. However, even soap and salt could be considered herbicides because they can have the same effects. Herbicides are used for convenience, since pulling weeds can be hard work, but there are many health and environmental risks.
There are other options to herbicide for killing unwanted or invasive species plants.
For example, many farms use goats to clean up overgrown fields, and besides getting rid of a problem, they save money on food for the animals.
Another way to destroy unwanted plants is to pour boiling water on them. This only kills the plant desired and does not harm soil or ground water.
While certain plants may be considered weeds by humans, they may be valuable food sources for animals, even pets, birds and insects. Herbicides damage the balance of an ecosystem.
"The 20th century saw an increase in the use of herbicides to control weeds in agriculture. Some mid-20th century herbicides, like DDT, have been virtually eliminated via international agreements due to high levels of toxicity. However, many legal herbicides are still in use that have serious safety concerns." Garden Guides
Damage to Soil: Chemicals remain in the soil where crops were grown, and can increase to the point that land becomes completely unusable.
"Repeated use of the chemical glyphosate, the key ingredient in Roundup herbicide, impacts the root structure of plants, and 15 years of research indicates that the chemical could be causing fungal root disease, said Bob Kremer, a microbiologist with the US Department of Agriculture's Agricultural Research Service."
Damage to Water: Ground water can be polluted so much that it is undrinkable or unusable. Many people and farm animals get there water from wells, which when polluted with herbicides makes them sick.
Many species of plants have developed a resistance to herbicides because they have been so widely used. Farmers who plant GMO corn and soy beans usually do so because it is resistant to glyphosate, a key ingredient in "Round-Up" a popular herbicide, however, other plants that it is meant to kill have grown stronger and the herbicide does not have the effect desired by the user. Marestail is one plant that has developed glyphosate resistance.
Slow Food Upstate recommends never using herbicides since there are alternate ways to solve an invasive plant problem that will also protect the earth for future generations and future food supplies.