"Weed 'n feed" is common term for a lawn product that combines fertiliser with weed control. This combination allows one application to feed the lawn and kill the weeds. It is typically sold as a granular product which is applied by using a lawn spreader. There are two types of common lawn spreaders: broadcast and drop spreaders. Either will work for this application, but you will need to adjust the gate that controls the rate of delivery, according to the fertiliser manufacturer's instructions.
Read the instructions for your weed and feed to determine the rate of distribution. Adjust the spreader's rate control mechanism by turning it to the recommended setting.
Pour the fertiliser into the spreader's hopper until it is one inch from the top, or the amount necessary to cover the square-footage the area.
Water your lawn lightly with a hose or apply the fertiliser first thing in the morning to take advantage of the dew.
Start in one corner of your lawn. Pull the lever that opens the spreader's gate and start walking at a normal pace in a straight line along the edge of the lawn.
Turn off the gate as you approach the end of the lawn and make a 360 degree turn about four feet from your last line. Turning off the gate at the end of each row avoids over-fertilising this area.
Open the gate back up and walk parallel to your last line. The distance between runs will depend on how far your spreader throws the fertiliser. You don't want the rows to overlap, as this will create areas with double the application and may burn the lawn.
Continue this pattern until the entire lawn is covered evenly. Pour the unused fertiliser back into the bag and seal it shut.
Apply weed 'n feed products on a day with little wind. Wind can blow around the fertiliser, reducing the evenness of the application.
Do not water the lawn for 24 hours after the application. Avoid applying the product to flower and vegetable gardens.