Weed and Feed is a dual-action, granular lawn care product that combines fertilizer with an herbicide. It offers a convenient way to nourish the grass while eliminating weeds simultaneously. Understanding the separate timelines for the herbicide, which targets existing weeds, and the fertilizer, which promotes grass health, is key to setting realistic expectations. The speed of the results depends heavily on the specific chemical formulations and environmental conditions at the time of application.
Timeline for Weed Elimination
The “weed” component usually contains a post-emergent broadleaf herbicide designed to kill visible weeds like dandelions and clover. Initial signs of the herbicide working, such as curling, twisting, or yellowing foliage, typically appear within three to seven days after application. Complete weed death takes a longer period because the systemic herbicide must travel from the leaves down to the root system to fully eliminate the plant.
Total browning and wilting for common broadleaf weeds usually takes ten to fourteen days, but tougher weeds may require up to three weeks for total eradication. Some products include pre-emergent herbicides, which work preventatively by creating a chemical barrier in the soil to stop weed seeds from germinating.
To be effective against existing plants, the active ingredient must be absorbed through the weed’s leaves. The granular product must stick to the moist foliage, allowing the herbicide to be translocated throughout the plant. Successful application causes the weed to stop growing and show signs of phytotoxicity before eventually dying.
Timeline for Lawn Greening and Growth
The “feed” portion is a fertilizer blend containing nitrogen, phosphorus, and potassium, essential for grass health. The speed of the lawn’s response depends on the type of nitrogen source used in the formulation. Quick-release nitrogen provides an immediate surge of nutrients, resulting in noticeable greening of the turf within seven to fourteen days.
Other products use slow-release nitrogen, which is coated to break down gradually over several weeks. This prevents a sudden growth spurt, but visible greening takes longer to appear, often starting after the two-week mark. Full improvements in lawn density, root structure, and overall vigor typically become apparent over a period of three to four weeks.
The fertilizer stimulates the grass to grow vigorously and fill in spaces left by dying weeds. This rapid growth helps the turf crowd out new weeds and contributes to a denser, healthier appearance. Full benefits, such as increased resilience and long-term health, are realized over the subsequent six to eight weeks after application.
Critical Factors Affecting Speed and Efficacy
The effectiveness and speed of Weed and Feed are significantly influenced by the environment and the physiological state of the plants. Herbicide components are most effective when weeds are actively growing, ensuring the chemical is rapidly absorbed and moved throughout the plant’s system. Applying the product when weeds are stressed, such as during drought or unseasonably hot weather, dramatically reduces the speed and extent of the kill.
Soil temperature is a major factor, influencing both the grass’s ability to absorb fertilizer and the weed’s metabolic rate. When the soil is too cool, slow plant growth delays the absorption and action of the herbicide and the nutrient uptake of the fertilizer. Adequate soil moisture is also necessary for the granular product to dissolve, activating both the fertilizer and the herbicide for proper absorption.
Uneven application can lead to patchy results; too much product risks fertilizer burn, while too little results in poor weed control. Ensuring the lawn is damp before application helps the granules stick to the weed leaves, maximizing the herbicide’s efficacy. Proper coverage ensures the active ingredients are distributed consistently across the target areas.
Post-Application Care Requirements
Immediate post-application care is important for the product to function as intended. For products containing post-emergent herbicides, watering must be delayed for a specific period, typically between 24 and 48 hours. This delay allows the herbicide granules to remain in contact with and be absorbed by the weed foliage.
Mowing should also be avoided immediately following the treatment, usually for one to two days. This restriction ensures the herbicide is not removed from the weed leaves before it is fully absorbed and translocated.
After the initial waiting period, a light watering is often required to dissolve the remaining granules. This moves the fertilizer into the soil to begin feeding the grass roots.
If a second application is necessary to control persistent weeds or maintain fertilizer levels, it is recommended to wait at least six to eight weeks. This waiting period prevents the buildup of excessive chemicals in the soil, which could damage the turf or lead to over-fertilization. Following the manufacturer’s specific instructions for watering and mowing is the most reliable way to achieve expected results.