Weed-and-feed turf-care products are designed to fertilize the lawn while removing existing broad-leaf weeds. It is important to choose a type of weed and feed that doesn't harm your turf grass. Properly applying weed and feed when the grass is long will achieve optimal results.
Weed and Feed
Weed and feed products do not prevent weed seed from germinating. However, this herbicide type kills off existing broad-leaf weeds, such as dandelions and dollarweeds. This herbicide works by absorbing into the leaves of weeds. Once in the weedy plant's system, it moves into the root system or other areas of the plant and disrupts its ability to grow. The larger the surface area of the leaves the more product is absorbed. Therefore, mowing right before applying weed and feed will reduce its effectiveness.
Apply weed and feed when weeds are still in their seedling stage. Mature weeds are hardier to kill with weed and feed products. Mow your lawn two days before applying the product. The grass should be mowed down to a height that matches its specific growing requirements. For example, St. Augustine grass should be kept at 2 1/2 inches tall. Avoid taking more than one-third of the grass blade when mowing the lawn, because it weakens the root system of the grass.
Applying Weed and Feed
Water the lawn before applying weed and feed, so the product sticks to the leaves of your weeds. It is best to choose a time to apply the herbicide and fertilizer combination when there is 48 hours of dry weather, so the product doesn't wash off the grass. Spread weed and feed evenly over the lawn. Missing areas will result in dense populations of weed growth and break up the uniformity of the grass. Wait two days before mowing the lawn again, so the chemicals are absorbed into the grass blades.
Weed and feed should be used on lawns that have green up for the season or come out of dormancy.Certain types of lawns should not be given Weed and Feed products. Bermuda, centipede and zoysia lawns need weed removing herbicide prior to coming out of dormancy, but should not be fertilized before they green up, according to gardening writer, Walter Reeves. Gardeners who are growing these grass types must apply herbicide in the early spring when grass is just starting to grow and wait for late spring or summer to fertilize.