Liquid weed and feed is a convenient lawn care product that combines a fertilizer with a selective post-emergent herbicide. The fertilizer delivers essential nutrients that immediately feed the turfgrass for rapid greening and growth. Simultaneously, the herbicide targets broadleaf weeds such as dandelions and clover that are already visible in the lawn. This dual-action approach eliminates existing weeds while boosting the desirable grass to fill in the newly opened spaces.
Timing the Application
Successful application depends on environmental factors that encourage weed activity and product absorption. The optimal time for treatment is typically in the spring, after the turf has been mowed once or twice, and again in the early fall. Applying the product when weeds are small and actively growing ensures they transport the herbicide deep into their root systems for a complete kill.
The ambient air temperature must be consistently within a range of 60 to 90 degrees Fahrenheit. Temperatures below this range reduce weed metabolic activity, making absorption less effective. Applying the product when temperatures exceed 90 degrees can cause the herbicide and fertilizer salts to scorch or “burn” the lawn.
Weather conditions must be calm, with wind speeds ideally below 10 miles per hour, to prevent the liquid spray from drifting off-target. Ensure no rainfall is forecasted for the next 24 to 48 hours following the application. The lawn must be dry when spraying so the herbicide droplets adhere directly to the weed foliage, maximizing absorption.
Preparation and Mixing Ratios
Before mixing any product, determine the precise size of the area you intend to treat, as application rates are based on square footage. Measure the length and width of the lawn, breaking up oddly shaped sections into smaller, measurable squares or rectangles. Knowing the exact square footage ensures you apply the correct concentration of herbicide and fertilizer, typically measured per 1,000 square feet.
Always consult the product label for the specific dilution rate. A common rate for concentrates is around 4 to 6.4 fluid ounces per 1,000 square feet, mixed with enough water for uniform coverage. For most home applications, a ratio yielding approximately one gallon of finished solution per 1,000 square feet is standard.
The choice of sprayer dictates the mixing process. A tank or pump sprayer requires manual pre-mixing of the concentrate with water, providing high precision beneficial for herbicides. A hose-end sprayer is less accurate as it automatically mixes the concentrate with water, but it is more convenient for covering large areas quickly.
When handling and mixing the liquid concentrate, wearing personal protective equipment is necessary to minimize exposure. Wear long pants, a long-sleeved shirt, closed-toe shoes, and unlined chemical-resistant gloves. Eye protection, such as safety glasses or goggles, is important during the measuring and pouring of the concentrated liquid.
Spraying Technique and Coverage
The primary objective is to coat the surface of the weed leaves evenly without causing the product to run off or puddle on the soil. Maintain a low spray pressure to produce larger droplets that are less prone to drifting. Hold the pump sprayer nozzle approximately 18 to 24 inches above the turf canopy to keep the spray pattern concentrated.
Move across the lawn at a slow, controlled, and uniform walking speed to ensure consistent distribution over the measured area. Spray in a methodical, back-and-forth grid pattern, such as North to South, allowing for a slight overlap of the spray pattern on each pass. This overlapping technique prevents unsightly untreated stripes from appearing in the lawn.
For maximum coverage, some applicators split the total mixture in half. They apply the first half in a North-South pattern and the second half in a perpendicular East-West pattern. This cross-hatch method guarantees the most uniform application without over-saturating the turf.
Protecting non-target plants, such as flowers and shrubs, is necessary because the herbicide will kill any broadleaf plant it touches. Never spray when the wind is gusting or blowing directly toward a sensitive area. For added protection, use a piece of cardboard or a dedicated spray shield to physically block the spray from reaching desirable plants.
Post-Application Instructions
After spraying, a short waiting period is required to ensure the systemic herbicide is fully absorbed by the target weeds. The treated area must remain dry for a minimum of 24 hours, and preferably 48 hours, to allow the chemicals to translocate down to the root. Watering or heavy rain during this period will wash the product off the leaves, rendering the herbicide ineffective.
Avoid mowing the lawn for at least two to three days following the application. Mowing too soon removes the herbicide from the weed leaves before it has had time to work. Also, avoid mowing immediately before application, as weeds need sufficient leaf surface area to absorb the liquid spray.
Cleaning the application equipment promptly is necessary to prevent clogs and corrosion. Rinse the tank several times with clean water, thoroughly flushing the wand, hose, and nozzle. Spray the resulting dilute rinse water back onto the already treated lawn area to safely dispose of any residual chemical.
Any remaining concentrated product should be stored in its original container in a cool, dry, and shaded location, safely out of reach of children and pets. Proper storage maintains the chemical integrity of the product and extends its shelf life.