Weed and feed products combine two lawn care functions: fertilizing the grass and eliminating broadleaf weeds like dandelions and clover. These dual-action granular products contain both turf nutrients and a selective herbicide to simplify the lawn treatment process. The key to successfully treating a large area is calculating the precise amount of product needed to cover 1 acre (43,560 square feet). Applying too little results in spotty weed control and nutrient deficiency, while over-application risks chemical burn to the turf. Accurate calculation is necessary to ensure both effectiveness and the health of the entire lawn.
Calculating the Total Product Needed
The total quantity of weed and feed required for a 1-acre area depends entirely on the coverage rate specified on the product packaging. To determine the number of bags you need, divide the total area of 43,560 square feet by the square footage the bag is rated to cover. This required rate is typically measured in square feet per bag, and it varies significantly between manufacturers and product types.
For instance, if a bag of weed and feed covers 4,000 square feet, you would need 11 bags (10.9 rounded up) to treat the full acre. Alternatively, if you select a bulk bag rated for 15,000 square feet, the requirement drops to four bags when rounding up for the area.
This difference illustrates why checking the label is important, as the need can range from three to over ten bags for the same 1-acre area. The weight of the bag is less significant than the actual coverage rate, which is set by the manufacturer to deliver the correct active ingredients.
How Product Labels Determine Coverage Rates
A product’s labeled coverage rate is determined by the concentration of its active components. The fertilizer strength, represented by the NPK ratio, dictates how many pounds of product must be applied per unit area to deliver a specific amount of nitrogen to the grass. For example, a manufacturer aims to deliver 1.0 pound of actual nitrogen per 1,000 square feet, which then establishes the application weight and the overall bag coverage.
The concentration of selective herbicides, such as 2,4-D or Dicamba, directly influences the application rate. The product must be spread thickly enough to deliver a lethal dose of the herbicide to the target weeds without harming the desirable turfgrass. If a formulation contains a lower percentage of active herbicide, the coverage rate will be lower, meaning you need more product per acre to achieve effective weed control.
The physical form of the product also plays a role. Granular weed and feed must be applied to stick to the weed leaves for the herbicide to work. This requirement, combined with the need to evenly distribute the nutrient load, determines the final square footage listed on the bag. Following the manufacturer’s specific rate ensures that both the fertilizer feeds the grass and the herbicide controls the weeds at their intended concentrations.
Essential Steps Before Application
Before beginning the application process across 1 acre, several preparatory steps must be completed to ensure the product works correctly. First, accurately measuring the specific area to be treated is necessary, as few properties are exactly 43,560 square feet. Knowing the precise square footage prevents waste and guarantees the calculated amount of product is distributed over the correct space.
The most important logistical step is the calibration of your spreader, whether it is a drop or rotary model. Manufacturers provide a recommended setting on the bag that corresponds to their specific coverage rate and the equipment. Failing to set the spreader accurately will result in an incorrect delivery rate, leading to either chemical burn from over-application or poor weed control from under-application.
Granular weed and feed requires the lawn to be slightly moist so that the particles adhere to the leaves of the weeds. This contact allows the herbicide to be absorbed, maximizing the product’s effectiveness. For such a large area, it is advisable to apply the material in two perpendicular passes over smaller, marked sections to ensure a uniform distribution across the entire acre.