Hello Chang,

Unfortunately, the most effective and safest way to remove the weeds from the lawn is to manually dig them out. Just about any other method will have tradeoffs that you will need to consider.

The “home remedy” containing salt and vinegar is a “burn down” solution. It kills the greenery above ground but does little to affect the root and kill the weed. This can be somewhat effective on newly sprouted annual weeds but will do little to deter well established annual or perennial weeds. It is nonselective and will affect the desirable grass as well. Also, acid and salt are not the best things to apply to your soil.

There are “natural” weed killers that are doing considerable advertising this year, but they are burn down products as well. They are not selective either and will kill the grass foliage the same as the weed leaves.

There are weed killer products that come in a weed and feed or strictly a herbicide form that are effective against broad leaf weeds, but do not affect the grass plants. They can be very effective against dandelions, plantains, violets, ground ivy and clover. The labels of all of them are required to carry an advisory stating how long children and pets should be kept off the area before it is safe to return.

People have different comfort levels and perceptions on safety when it comes to pesticide use, and we respect that. While the EPA requires a wide variety of data on environmental and personal risk before they register a pesticide and permit its sale, some may feel more comfortable avoiding pesticides all together.

Interestingly, you mentioned crabgrass. Only recently were there chemical pesticides that could selectively kill crabgrass after it germinated. Crabgrass is usually treated with a pre-emergent herbicide that prevents the seeds from forming viable plants. An all-natural effective solution for crabgrass is corn gluten meal. If you apply corn gluten meal to the lawn at the right time in the spring (about the time that the yellow forsythia bushes are in bloom), it will prevent crabgrass seed from germinating. See this webpage for more info and further references: https://www.canr.msu.edu/news/corn_gluten_acts_an_alternative_organic_weed_control

Hope this helps.